Exposure to multi-metal mixtures is a public health concern, but their joint association with adult asthma remains insufficiently characterized, particularly in Asian populations. This study aimed to investigate the joint association between urinary multi-metal mixtures and adult asthma and to identify the metals contributing to this association. We conducted a case-control study including 551 adults with asthma and 551 age- and sex-matched controls in China. Urinary concentrations of 23 metals were measured by ICP-MS. Principal component analysis (PCA), weighted quantile sum regression (WQS), quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR) were used to evaluate mixture associations. Across the mixture models, the 23-metal mixture showed a positive joint association with adult asthma. Titanium (Ti), uranium (U), and molybdenum (Mo) showed relatively consistent positive contributions, whereas iron (Fe), manganese (Mn), and nickel (Ni) showed inverse contributions. Although larger positive point estimates were observed among females and participants aged ≤ 40 years, formal interaction tests did not indicate statistically significant heterogeneity. BKMR suggested potential nonlinear and pairwise patterns involving multiple metals, particularly U, Ti and vanadium (V), but these findings were exploratory and do not establish synergistic toxicity. Overall, these findings suggest an association between urinary multi-metal mixtures and adult asthma but do not establish causality. Prospective studies are needed to clarify the temporal sequence and underlying biological pathways.

Cadmium is a highly toxic heavy metal that damages multiple organ systems. However, the effects of cadmium on male reproductive function remain incompletely understood. The present work established a cadmium-exposed model of mouse testicular Sertoli cells (TM4 cells) to explore the effect of cadmium on ferroptosis in these cells and the underlying mechanisms involved. The experimental results showed that with increasing toxicant exposure, cell viability, intracellular glutathione (GSH) content, mitochondrial membrane potential, as well as Solute Carrier Family 7 Member 11 (SLC7A11) and Glutathione Peroxidase 4 (GPX4) expression were gradually decreased. In contrast, the endoplasmic reticulum stress marker Glucose-Regulated Protein 78 and proteins involved in the PERK-ATF4-CHOP pathway were significantly upregulated. Combined treatment with the PERK inhibitor GSK2656157 markedly reduced intracellular oxidative stress, elevated GSH levels and the expression of SLC7A11, GPX4 and Nuclear factor erythroid 2-related factor 2 (Nrf2), restored mitochondrial membrane potential, and downregulated key proteins in the PERK-ATF4-CHOP pathway. Similarly, combined treatment with the ferroptosis inhibitor Ferrostatin-1 significantly ameliorated cellular redox homeostasis, increased GSH content, upregulated the expression of SLC7A11, GPX4, Nrf2 and core ferroptosis regulators, and effectively recovered mitochondrial membrane potential. Therefore, our research indicates that cadmium can induce oxidative stress in TM4 cells, thereby activating the PERK-ATF4-CHOP signaling pathway. This leads to a disruption of the cells' ability to clear oxidative stress products, causing a significant accumulation of lipid peroxidation products within the cells. As a result, TM4 cells undergo ferroptosis, causing damage to the male (masculine) reproductive system functions.

Purpose This study investigated how differential macrophage polarization dynamics drive the severity of post-traumatic joint contracture (PTJC) compared to non-traumatic joint contracture (NTJC). Methods We first performed a bioinformatic analysis intersecting the human dataset GSE135854 with macrophage polarization gene sets to identify core pathogenic targets. Subsequently, rat models of surgically-induced post-traumatic contracture and immobilization-only non-traumatic contracture were established. This study assessed temporal changes in joint range of motion, histopathological fibrosis, macrophage polarization dynamics, and molecular pathways including TLR4/MyD88/NF-κB signaling and fibrotic mediators. Results Bioinformatic profiling identified 1,137 core genes linking macrophage polarization to arthrofibrosis, which were enriched in immune-related biological processes and the NF-kappa B signaling pathway. Clinically, TLR4 and MYD88 were downregulated in end-stage human fibrosis, suggesting a temporal resolution of early inflammatory signals. In rat models, PTJC exhibited significantly more severe contracture and aggressive fibroproliferative remodeling compared to NTJC. Mechanistically, PTJC induced a robust early surge in M1 macrophages via TLR4/MyD88/NF-κB pathway activation, followed by a delayed, pathological M2 response. In contrast, NTJC showed milder macrophage dynamics. The discrepancy between early-stage rat models (upregulation) and end-stage clinical samples (downregulation) underscores the TLR4 axis as an early initiator of the fibrotic cascade. Conclusion Trauma drives severe contracture via a specific, aggressive fibroproliferative cascade involving dysregulated macrophage plasticity and regional tissue crosstalk. Effective management of PTJC requires phase-specific strategies: targeting the early TLR4-mediated M1 surge and modulating the late-stage pathological M2 response, distinct from the prophylactic needs of NTJC.

Cadmium (Cd), an environmental toxicant, accumulates in the human body and damages the male reproductive system. To investigate the molecular mechanisms underlying Cd-induced reproductive toxicity, we used GC-2spd cells and treated them with CdCl2. Additionally, we added 2-APB (an inhibitor of the IP3R) and STF-083010 (an inhibitor of IRE1) to investigate whether they could ameliorate Cd-induced reproductive toxicity. Confocal microscopy and flow cytometry confirmed that CdCl2-treated GC-2spd cells displayed imbalance of calcium homeostasis, with upregulation of the expression of the IP3R, a key pathway for endoplasmic reticulum (ER) Ca2+ release. Furthermore, the ER stress (ERS) effector protein IRE1 expression was also increased, suggesting that Cd activated ERS and the IRE1 pathway by disrupting calcium homeostasis. Previous studies have shown that ERS induces autophagy. We performed the MDC assay to detect autophagosome formation, revealing increased expression of autophagy-related proteins LC3-II/LC3-I and Beclin-1 in response to Cd treatment. In contrast, treatment with 2-APB and STF-083010 inhibited autophagy and mitigated cell death. This inhibitory effect may be due to 2-APB blocking IP3R-mediated Ca2+ release, alleviating imbalance of calcium homeostasis, while STF-083010 inhibits IRE1, restoring ER homeostasis and reducing autophagy. These findings suggest that imbalance of calcium homeostasis activates the IRE1 pathway-mediated ERS, leading to excessive autophagy and male reproductive toxicity. Conversely, the addition of 2-APB and STF-083010 reversed these effects, synergistically restoring intracellular Ca2+ homeostasis and inhibiting ERS to promote cell health. This study provides a new therapeutic strategy for Cd-induced male reproductive disorders.

BACKGROUND:Smoking is a well-established risk factor for COPD, but the impact of time from waking to first cigarette (TWFC) remains underexplored, particularly regarding its interactions. OBJECTIVES:We aim to investigate the TWFC-COPD association among current smokers and evaluate its interactions with genetic susceptibility, smoking pack-years and difficulty not smoking for one day (DNSD). METHODS:Using data from 302,412 UK Biobank participants, a COPD genetic risk score (GRS) was developed from 22 independent established SNPs associated with COPD and related phenotypes. Cox proportional hazards models was used to estimate adjusted hazard ratios (aHRs, 95% CIs), and assesse additive and multiplicative interactions. RESULTS:Over a median follow-up of 12.42 years, 13,131 incident COPD cases were identified. Compared with never smokers, current smokers exhibited a significant inverse gradient association between shorter TWFC and increased COPD risk (P trend<0.001), with aHRs (95% CIs) increasing from 4.18 (3.66-4.78) for TWFC >120 min to 8.76 (8.01-9.58) for TWFC <5 min. Compared to current smokers with TWFC >120 min and low genetic risk, those with the shortest TWFC (<5 min) and high genetic risk had the highest COPD risk (aHR=2.85, 95% CI: 2.34-3.46), with a tendency toward additive interaction (RERI=0.26, 95% CI: -0.06-0.58; AP=8%, 95% CI: -0.03-0.19). Similarly, TWFC <5 min combined with higher pack-years (aHR=3.08, 95% CI: 2.66-3.57) or greater DNSD (aHR=5.14, 95% CI: 4.22-6.25) elevated the risk, with significant additive interactions. CONCLUSIONS:Shorter TWFC is strongly associated with increased COPD risk among current smokers, amplified by high genetic susceptibility to COPD, higher smoking pack-years, and greater DNSD.

Background:Studies have suggested that folate may mitigate the impact of exposure to environmental chemicals. We aimed to explore the relationship between blood folate biomarker concentrations and urine phthalate metabolites. Methods:Based on data from the National Health and Nutrition Examination Survey spanning 2005 to 2016, 8,218 participants with measurements of folate biomarkers in blood and phthalates exposure in urine were included. Survey generalized linear regression models and restricted cubic spline and generalized additive models were used to assess the associations between blood folate biomarker and urine phthalate metabolites. Results:After adjusting for covariates, each unit increase in the natural logarithm-transformed serum folate concentration was associated with significant reductions of 7.41% in MEHP and 7.10% in MEHHP. After further adjustment for HEI-2020, these inverse associations strengthened to 8.11% (95% CI: -13.18, -2.76%) for MEHP and 8.07% (95% CI: -14.20, -1.52%) for MEHHP. Quartile analysis revealed that participants in the highest serum folate quartile exhibited significantly lower levels of MEHP, MEOHP, MECPP, and MEHHP compared to those in the lowest quartile (all p for trend <0.01). Furthermore, restricted cubic spline analyses and generalized additive models demonstrated significant inverse linear relationships between serum folate concentrations and MEHP, MEOHP, and MEHHP levels. No significant associations were observed between red blood cell folate concentrations and phthalate metabolites. Conclusion:These findings indicate that folate is associated with reduced concentrations of phthalate metabolites in urine, which may hold significant relevance for the utilization of folate as a strategy to reduce the accumulation of phthalate burden.

Effective instructional approaches for fostering students' competences in public health education remain to be explored. This study aimed to integrate the bridge-in, objective, pre-assessment, participatory learning, post-assessment, and summary (BOPPPS) framework with problem-based learning (PBL), team-based learning (TBL), and case-based learning (CBL) to develop a novel instructional model, termed the BOPPPS-integrated model (BIM), and to assess the influences of single and multiple BIM interventions on the competences of undergraduate public health students. A two-stage study was conducted by a quasi-experimental pilot study and a cross-sectional survey. First, the quasi-experiment compared a traditional lecture-based learning (LBL) group (n = 50) with a BIM group (n = 48) to evaluate the effect of a single BIM intervention. Second, a cross-sectional study was conducted to analyze the impacts of multiple BIM sessions across three groups: control (n = 96), basic intervention (1–2 times BIM, n = 66), and intensive intervention (≥ 3 times BIM, n = 62). All participants completed a self-administered questionnaire designed to evaluate seven competence dimensions: information literacy, summarization, expressive communication, critical thinking, self-directed learning, teamwork, and objective evaluation, which are essential for public health students to address complex public health challenges. Students who received single and multiple BIM instructional sessions scored significantly higher in information literacy, expressive communication, and teamwork than those who received LBL method (P < 0.05). Multiple BIM interventions further improved scores in summarization, self-directed learning, and objective evaluation (P < 0.05). The scores of six dimensions like information literacy, summarization, expressive communication, self-directed learning, teamwork, and objective evaluation showed an upward trend as the number of interventions increased (P for trend < 0.05). A single BIM intervention effectively improved students’ competences in information literacy, teamwork, and expressive communication. Additionally, multiple BIM interventions not only consolidated these competences but also fostered summarization, self-directed learning, and objective evaluation, thereby highlighting the importance of BIM in developing students’ competences in public health education.

Cilia are microtubular structures extending from the surface of most mammalian cells. They can be categorized as motile cilia and primary sensory cilia. Both types possess intraflagellar transport (IFT) machinery, composed of unique protein complexes that travel along the microtubules to deliver proteins for ciliary and flagellar assembly, disassembly, and homeostasis. Although the role of IFT in primary cilia formation has been well studied, little is known about its role in mammalian motile cilia assembly. We generated conditional knockout mice by breeding floxed Ift140 mice with the FOXJ1-Cre transgenic mouse line to specifically delete Ift140 from cells that assemble motile cilia. Mice with Ift140 deficiency did not have laterality defects or gross; however most died prior to sexual maturity. Those mutants that survived to adulthood were completely infertile. Males demonstrated abnormal spermatogenesis associated with reduced sperm count and motility, together with short length flagella, and abnormal morphology. Cilia length was diminished in the epithelial cells of the efferent ductules and airways. Cilia from cultured tracheal epithelial cells were also short and had reduced beat frequency (CBF). Ultrastructural studies revealed the presence of inner and outer dynein arms, but an abnormal central apparatus, and the accumulation of particles within the cilia. Overall, the short length and abnormal localization of ciliary proteins in Ift140 conditional mutants resulted in inadequate cilia function despite proper localization of the dynein motor complexes. We propose a key role of Ift140 for motile cilia assembly in certain tissues and suggest that genetic alterations of IFT140 could be associated with motile ciliopathies.

To investigate the intervention effect of extracorporeal shock wave combined with manual traction on fixation-induced knee contracture and its influence on PTEN-PI3K/AKT signaling pathway. Thirty-six SD male rats were randomly divided into six groups. The left knee joints were not fixed in the control group (C group). Rats in other groups underwent brace fixation in the extended position of the left knee. After 4 weeks of bracing, it is randomly divided into five groups: Model group (M group), natural recovery group (NR group), extracorporeal shock wave treatment group ( ET group), manual traction group (MT group), and extracorporeal shock wave combined with manual traction group (CT group). Joint range of motion (ROM) of left knee was carried out to assess joint function. Hematoxylin and eosin (HE) staining and Masson staining were respectively used to assess the cell number and collagen deposition expression. Immunohistochemical staining and Western blot were used to assess protein levels of phosphatase and tensin homolog ( PTEN), phosphatidylinositol 3-kinase (PI3K), and protein kinase B (AKT). The combined therapy was more effective than extracorporeal shock wave therapy or manual traction alone against the joint ROM, cell number and the collagen deposition, low- expression of PTEN, and overexpression of PI3K/AKT in the anterior joint capsule of rats with knee extension contracture. Extracorporeal shock wave combined with manual traction can promote the histopathological changes of anterior joint capsule fibrosis, upregulate the protein expression of PTEN and downregulate the protein expression of PI3K/AKT in the fibrotic joint capsule in a rat joint contracture model.

Di-(2-ethylhexyl) phthalate (DEHP), a widely used plasticizer, could cause male reproductive toxicity by disrupting spermatogenesis. Piwi-interacting RNAs (piRNAs) are a small non-coding RNAs specifically highly expressed in the germline and interact with PIWI proteins to regulate spermatogenesis. Accumulating studies have confirmed that environmental poisons could induce male reproductive injury via altering piRNA expression. However, it remains unclear whether DEHP causes male reproductive dysfunction by perturbing piRNA expression levels. In this study, we conducted piRNA microarray expression analyses on testes of DEHP-exposed and control male rats and performed some in vitro and in vivo studies to explore the role of piRNA on DEHP-induced male reproductive toxicity. Our results showed that DEHP exposure leaded to changed expression profiles of piRNAs in pubertal male rat testes. And bioinformatics analyses revealed that down-regulated piR-rno-26751 probably targeted Insr mRNA expression regulation. Results from gene and protein expression tests demonstrated that DEHP caused decreased expression level of INSR mainly in spermatogonia. Moreover, MEHP, the main metabolite of DEHP resulted in cell apoptosis and down-regulation of INSR and its downstream p-IRS1, p-PI3K, p-AKT and p-FOXO1 in GC-1spg cells. Conversely, overexpression of INSR restored cell apoptosis and the down-regulation of the above proteins in GC-1spg cells. In conclusion, these findings suggest that DEHP-induced down-regulation of piR-rno-26751 targets the suppression of INSR, leading to apoptosis of spermatogonia in pubertal male rats.

Environmental exposure to crystalline silica (CS) particles is common and occurs during natural, industrial, and agricultural activities. Prolonged inhalation of CS particles can cause silicosis, a serious and incurable pulmonary fibrosis disease. However, the underlying mechanisms remain veiled. Herein, we aim to elucidate the novel mechanisms of interleukin-11 (IL-11) driving fibroblast metabolic reprogramming during the development of silicosis. We observed that CS exposure induced lung fibrosis in mice and activated fibroblasts, accompanied by increased IL-11 expression and metabolic reprogramming switched from mitochondrial respiration to glycolysis. Besides, we innovatively uncovered that elevated IL-11 promoted the glycolysis process, thereby facilitating the fibroblast-myofibroblast transition (FMT). Mechanistically, CS-stimulated IL-11 activated the extracellular signal-regulated kinase (ERK) pathway and the latter increased the expression of hypoxia inducible factor-1α (HIF-1α) via promoting the translation and delaying the degradation of the protein. HIF-1α further facilitated glycolysis, driving the FMT process and ultimately the formation of silicosis. Moreover, either silence or neutralization of IL-11 inhibited glycolysis augmentation and attenuated CS-induced lung myofibroblast generation and fibrosis. Overall, our findings elucidate the role of IL-11 in promoting fibroblast metabolic reprogramming through the ERK-HIF-1α axis during CS-induced lung fibrosis, providing novel insights into the molecular mechanisms and potential therapeutic targets of silicosis.

Cadmium (Cd) is a harmful environmental pollutant that disrupts public health, including respiratory, digestive, and reproductive systems. In this study, male rats were exposed to CdCl2 at a dose of 3 mg/kg by oral for 28 days to investigate the impact on spermatogenesis. Testis tissue samples were collected after sacrifice, and piRNA expression levels were measured using piRNA microarray and qPCR. PiRNAs, specialized molecules involved in spermatogenesis, were examined. CdCl2 exposure led to disrupted piRNA expression, particularly in piRNADQ759395 in rats. This piRNA was found to have a binding site with p53, and a similar piRNA-DQ717867 was discovered in mice. In GC-2spd cells, CdCl2 exposure increased piRNA-DQ717867 expression, which resulted in cell cycle arrest and abnormal expression of cell cycle-related proteins. The activation of p53-related pathways and disruptions in cell cycle regulation were also observed. Antagomir-717867 transfections and PFT-a pretreatment in GC-2spd cells supported the involvement of piRNA-DQ717867 in regulating cell cycle-related proteins. This study suggests that Cd exposure induces abnormal expression of piRNA-DQ759395 in rat testis and that piRNA-DQ717867 may regulate p53, causing cell cycle abnormalities in GC-2spd cells. These findings help understand the mechanisms of male reproductive toxicity caused by Cd exposure and emphasize the role of piRNAs in cell cycle regulation and male reproductive health.

Joint contracture is one of the common diseases clinically, and joint capsule fibrosis is considered to be one of the most important pathological changes of joint contracture. However, the underlying mechanism of joint capsule fibrosis is still controversial. The present study aims to establish an animal model of knee extending joint contracture in rats, and to investigate the role of hypoxia-mediated pyroptosis in the progression of joint contracture using this animal model. 36 male SD rats were selected, 6 of which were not immobilized and were used as control group, while 30 rats were divided into I-1 group (immobilized for 1 week following 7 weeks of free movement), I-2 group (immobilized for 2 weeks following 6 weeks of free movement), I-4 group (immobilized for 4 weeks following 4 weeks of free movement), I-6 group (immobilized for 6 weeks following 2 weeks of free movement) and I-8 group (immobilized for 8 weeks) according to different immobilizing time. The progression of joint contracture was assessed by the measurement of knee joint range of motion, collagen deposition in joint capsule was examined with Masson staining, protein expression levels of HIF-1α, NLRP3, Caspase-1, GSDMD-N, TGF-β1, α-SMA and p-Smad3 in joint capsule were assessed using western blotting, and the morphological changes of fibroblasts were observed by transmission electron microscopy. The degree of total and arthrogenic contracture progressed from the first week and lasted until the first eight weeks after immobilization. The degree of total and arthrogenic contracture progressed rapidly in the first four weeks after immobilization and then progressed slowly. Masson staining indicated that collagen deposition in joint capsule gradually increased in the first 8 weeks following immobilization. Western blotting analysis showed that the protein levels of HIF-1α continued to increase during the first 8 weeks of immobilization, and the protein levels of pyroptosis-related proteins NLRP3, Caspase-1, GSDMD-N continued to increase in the first 4 weeks after immobilization and then decreased. The protein levels of fibrosis-related proteins TGF-β1, p-Smad3 and α-SMA continued to increase in the first 8 weeks after immobilization. Transmission electron microscopy showed that 4 weeks of immobilization induced cell membrane rupture and cell contents overflow, which further indicated the activation of pyroptosis. Knee extending joint contracture animal model can be established by external immobilization orthosis in rats, and the activation of hypoxia-mediated pyroptosis may play a stimulating role in the process of joint capsule fibrosis and joint contracture.

An international high impact journal exploring the underlying science behind the function, interactions and design of biomaterials rsc.li/biomaterials-scienceThe Royal Society of Chemistry is the world's leading chemistry community.Through our high impact journals and publications we connect the world with the chemical sciences and invest the profits back into the chemistry community.

Graphene-based nanomaterials (GBNs) consist of a single or few layers of graphene sheets or modified graphene including pristine graphene, graphene nanosheets (GNS), graphene oxide (GO), reduced graphene oxide (rGO), as well as graphene modified with various functional groups or chemicals (e.g., hydroxyl, carboxyl, and polyethylene glycol), which are frequently used in industrial and biomedical applications owing to their exceptional physicochemical properties. Given the widespread production and extensive application of GBNs, they can be disseminated in a wide range of environmental mediums, such as air, water, food, and soil. GBNs can enter the human body through various routes such as inhalation, ingestion, dermal penetration, injection, and implantation in biomedical applications, and the majority of GBNs tend to accumulate in the respiratory system. GBNs inhaled and substantially deposited in the human respiratory tract may impair lung defenses and clearance, resulting in the formation of granulomas and pulmonary fibrosis. However, the specific toxicity of the respiratory system caused by different GBNs, their influencing factors, and the underlying mechanisms remain relatively scarce. This review summarizes recent advances in the exposure, metabolism, toxicity and potential mechanisms, current limitations, and future perspectives of various GBNs in the respiratory system.

Objective: To study Chinese nurses’ overall perception of physical activity and explore potential strategies to promote their regular leisure-time physical activity levels. Methods: Using descriptive qualitative research methods, semistructured interviews were conducted with 30 nurses from a tertiary hospital in Wuhan, China, from September 2022 to May 2023. Content analysis was used to analyze the data and extract the themes. Results: Five themes were identified: 1) lack of awareness of the recommended physical activity guidelines; 2)benefits of physical activity; 3) current status of physical activity; 4)influencing factors of regular leisure-time physical activity; and 5) strategies to promote regular leisure-time physical activity. Conclusions: Health administrative departments and medical institutions should attach great importance to the popularization of physical activity knowledge and promotion of physical activity in nurses. By strengthening propaganda and education, and to provide scientific guidance and effective intervention, promote the nurses to participate in leisure physical activities regularly, to ensure their physical and mental health, improve medical service quality.

Environmental exposure to crystalline silica particles can lead to silicosis, which is one of the most serious pulmonary interstitial fibrosis around the world. Unfortunately, the exact mechanism on silicosis is unclear, and the effective treatments are lacking to date. In this study, we aim to explore the molecular mechanism by which interleukin-11 (IL-11) affects silica particles-induced lung inflammation and fibrosis. We observed that IL-11 expressions in mouse lungs were significantly increased after silica exposure, and maintained at high levels across both inflammation and fibrosis phase. Immunofluorescent dual staining further revealed that the overexpression of IL-11 mainly located in mouse lung epithelial cells and fibroblasts. Using neutralizing anti-IL-11 antibody could effectively alleviate the overexpression of pro-inflammatory cytokines (i.e., interleukin-6 and tumor necrosis factor-α) and fibrotic proteins (i.e., collagen type I and matrix metalloproteinase-2) induced by silica particles. Most importantly, the expressions of IL-11 receptor subunit α (IL-11Rα), Glycoprotein 130 (GP130), and phosphorylated extracellular signal-regulated kinase (p-ERK) were significantly increased in response to silica, whereas blocking of IL-11 markedly reduced their levels. All findings suggested that the overexpression of IL-11 was involved in the pathological of silicosis, while neutralizing IL-11 antibody could effectively alleviate the silica-induced lung inflammation and fibrosis by inhibiting the IL-11Rα/GP130/ERK signaling pathway. IL-11 might be a promising therapeutic target for lung inflammation and fibrosis caused by silica particles exposure.

Recent studies have shown that immobilization enhances reactive oxygen species (ROS) production and mitophagy activity in atrophic skeletal muscle. However, there are relatively few studies examining the biological changes and underlying mechanisms of skeletal muscle during remobilization. In this study, we aimed to investigate the effects of remobilization on skeletal muscle and explore the role of BNIP3-dependent mitophagy in this process. Thirty rats were randomly divided into six groups based on immobilization and remobilization time: control (C), immobilization for two weeks (I-2w), and remobilization for one day (R-1d), three days (R-3d), seven days (R-7d), and two weeks (R-2w). At the end of the experimental period, the rectus femoris muscles were removed and weighed, and the measurements were expressed as the ratio of muscle wet weight to body weight (MWW/BW). Sirius Red staining was performed to calculate the values of cross-sectional area (CSA) of rectus femoris. Oxidative fluorescent dihydroethidium was used to evaluate the production of ROS, and the levels of superoxide dismutase (SOD) were also detected. The morphological changes of mitochondria and the formation of mitophagosomes in rectus femoris were examined and evaluated by transmission electron microscope. Immunofluorescence was employed to detect the co-localization of BNIP3 and LC3B, while Western blot analysis was performed to quantify the levels of proteins associated with mitophagy and mitochondrial biogenesis. The total ATP content of the rectus femoris was determined to assess mitochondrial function. Within the first three days of remobilization, the rats demonstrated decreased MWW/BW, CSA, and ATP concentration, along with increased ROS production and HIF-1α protein levels in the rectus femoris. Results also indicated that remobilization triggered BNIP3-dependent mitophagy, supported by the accumulation of mitophagosomes, the degradation of mitochondrial proteins (including HSP60 and COX IV), the elevation of BNIP3-dependent mitophagy protein markers (including BNIP3, LC3B-II/LC3B-I, and Beclin-1), and the accumulation of puncta representing co-localization of BNIP3 with LC3B. Additionally, PGC-1α, which is involved in the regulation of mitochondrial biogenesis, was upregulated within the first seven days of remobilization to counteract this adverse effect. Our findings suggested that BNIP3-denpendent mitophagy was sustained activated at the early stages of remobilization, and it might contribute to the worsening of skeletal muscle atrophy.

OBJECTIVE:To study the effects of cadmium on autophagy in germ cells (GC-2 spd cells) through Ca2+ and IRE1 pathway.METHODS:The viability of GC-2 spd cells was determined using a CCK-8 assay to establish the concentration of cadmium treating . MDC staining was employed to assess autophagosome formation. Laser confocal microscopy and flow cytometry were utilized to measure cytoplasmic and endoplasmic reticulum (ER) Ca2+ levels. Western blot was conducted to evaluate the expression levels of proteins associated with the IRE1 signaling pathway and autophagy.RESULTS:As the concentration of cadmium increased, cell viability gradually decreased. The concentrations of cadmium were determined to be 2.5, 5, and 10 μmol/L. Compared with the control group, the IOD values of MDC fluorescence intensity within the cadmium group were all elevated (P<0.05), accompanied by elevated ratios of autophagy markers LC3-II/LC3-I and up-regulation of Beclin-1 protein expression (P<0.05). Cytoplasm Ca2+ levels gradually increased, while ER Ca2+ levels decreased (P<0.05). The expression of IP3R protein, the ER Ca2+ release pathway, was up-regulated (P<0.05). Additionally, the expressions of IRE1, XBP1s, CHOP, and GRP78 were up-regulated in the cadmium group (P<0.05).CONCLUSION:Cadmium exposure can induce dysregulation of calcium homeostasis in GC-2spd cells, activates the ER stress-induced IRE1 signaling pathway, and ultimately induces the occurrence of autophagy in GC-2spd cells.