Objective: Spinal cord injury (SCI) triggers an inflammatory cascade that often culminates in chronic neurological deficits. This study investigates a combined stimulation approach using lipopolysaccharide (LPS), interleukin-4 (IL-4), and transforming growth factor-beta (TGF-(3) to generate reparative-biased macrophages and evaluate their early effects after SCI. Methods: Bone marrow-derived macrophages (BMDMs) from Wistar rats were exposed to LPS, IL-4, and TGF-(3 for 24 h to generate reparative-biased hybrid macrophages (Mi) in vitro. The anti-inflammatory and proregenerative markers of Mi were characterised by qPCR, immunocytochemistry, and proteomic analysis via mass spectrometry. In vivo, rats with a T9/10 clip-contusion-compression SCI received either Mi transplantation or direct inducer administration at the lesion site. Histological outcomes and functional recovery were assessed and compared between injured and uninjured controls over a 14-day period. Results: Following 24 h induction, Mi exhibited significantly elevated mRNA and immunofluorescence expression of Arg1, as well as increased IL-10 mRNA levels, compared to na & iuml;ve BMDMs in vitro, while iNOS expression remained unchanged. Bioinformatic analysis of proteomic data from Mi revealed enrichment in metabolic activity, immune modulation, and phagocytosis pathways. Fluorescent microsphere phagocytosis assays demonstrated that Mi macrophages retained robust phagocytic activity. In vivo, transplantation of Mi resulted in elevated Arg1 expression and reduced iNOS and IL-1(3 levels 3 days after SCI, suggesting an anti-inflammatory shift. Immunohistochemical analysis demonstrated significantly reduced lesions and demyelinated areas, as well as increased preservation of motor neurons and oligodendrocytes. Mi transplantation was also associated with reduced apoptosis and improved early functional recovery at 14 days after SCI. Conclusion: This study suggests that LPS, IL-4, and TGF-(3-induced Mi macrophages display a reparative-biased hybrid profile that modulates inflammation, supports early tissue preservation, and promotes functional recovery after SCI, supporting Mi transplantation as a potential cell-based therapeutic strategy for further investigation. The translational potential of this article: Transplantation of this reparative-biased hybrid macrophage phenotype may provide a potential therapeutic strategy for the treatment of spinal cord injury.
Intervertebral disc degeneration (IVDD) is essentially a process of progressive destabilization of the continuous functional system of the intervertebral disc (IVD), which is formed by the nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous endplate (CEP). As distinct but interdependent regional functional units, the NP, AF, and CEP jointly maintain disc hydration, mechanical coordination, nutrient supply, and microenvironmental homeostasis. Local tissue degeneration not only disrupts regional function within the IVD but also promotes damage propagation across the disc through structural imbalance and microenvironmental deterioration. With a deeper understanding of regional heterogeneity and functional coupling within the IVD, tissue engineering strategies have evolved from simple tissue replacement toward regenerative approaches that integrate biological features, mechanical requirements, and microenvironmental regulation. According to the distinct tissue morphology, mechanical function, and pathological changes of the NP, AF, and CEP, various therapeutic strategies have been developed for different regions. These strategies provide a crucial foundation for local tissue repair and serve as functional modules that can be further integrated for whole-disc reconstruction. Building on these advances, recent research has increasingly shifted toward multi-region combined repair. Because restoration of disc function depends not on the independent regeneration of a single region, but on coordinated coupling among different regional functional units, integrated strategies place greater emphasis on interfacial continuity, coordinated load transfer, and long-term metabolic support. This review systematically summarizes tissue engineering strategies from regional functional units to integrated functional reconstruction for IVD regeneration, aiming to guide the development of more durable, stable, and function-oriented regenerative therapies for IVDD. The translational potential of this article This review provides a clinically oriented framework for translating intervertebral disc (IVD) tissue engineering from region-specific repair toward integrated functional reconstruction. By linking the distinct biological and mechanical requirements of the nucleus pulposus, annulus fibrosus, and cartilaginous endplate with multi-region and whole-IVD strategies, it identifies design principles relevant to patient-specific regenerative therapy. Particular emphasis is placed on therapeutic cell selection, biomaterial functionality, interfacial integration, nutrient transport, mechanical durability, and microenvironmental regulation. The review also highlights key barriers to clinical translation, including human-scale construct fabrication, limited nutrient supply, long-term mechanical failure, manufacturing reproducibility, regulatory complexity, immunogenicity, cost, and safety. By integrating recent preclinical, large-animal, and emerging clinical evidence, this work may help guide the development and evaluation of more durable, scalable, and clinically applicable regenerative strategies for IVDD, while supporting rational progression from experimental proof-of-concept studies toward clinically relevant therapeutic platforms.
Background Osteoarthritis and sarcopenia increasingly contribute to the burden of age-related musculoskeletal disorders. Xianling Gubao (XLGB), a traditional Chinese medicine formula, has been used for musculoskeletal conditions including osteoporosis and osteoarthritis; however, its effects on sarcopenia and structural joint degeneration, and the bioactive compounds potentially associated with dual musculoskeletal protection remain insufficiently defined. This study aimed to evaluate the effects of XLGB on sarcopenia and osteoarthritis, and to identify bioactive compounds associated with its musculoskeletal benefits. Methods Thirty 27-week-old male senescence-accelerated mouse prone 8 (SAMP8) mice were randomly assigned to aging control (SAMP8 with vehicle), low-dose XLGB (80 mg/kg/day), and high-dose XLGB (240 mg/kg/day) groups. Ten age-matched senescence-accelerated mouse resistant 1 (SAMR1) mice served as normal controls. An independent 27-week SAMP8 baseline cohort was included to characterize age-associated changes in muscle contractile and OA-related parameters. Sarcopenia-related changes were assessed by longitudinal body-weight-normalized grip strength, isolated muscle contraction tests, histology, transmission electron microscopy, and real-time quantitative PCR. Osteoarthritis-related changes were evaluated by micro-CT and histology. Exploratory correlation analyses were performed to examine statistical associations between selected sarcopenia- and osteoarthritis-related parameters. HPLC-UV-based chemical fingerprinting was used to characterize XLGB, and representative compounds were selected for CCK-8-based cytotoxicity evaluation and C2C12 myotube formation assays. Results At 37 weeks of age, SAMP8 mice exhibited coexisting sarcopenia- and osteoarthritis-related phenotypes, characterized by reduced muscle mass and contractile function, increased Osteoarthritis Research Society International (OARSI) scores, and impaired subchondral bone microstructure. XLGB produced distinct response patterns across tissues and doses: the lower dose improved selected ex vivo muscle contractile and mitochondrial parameters, whereas the higher dose more consistently attenuated cartilage degeneration; both doses improved selected subchondral bone parameters. Neither dose significantly improved body-weight-normalized forelimb grip strength or altered osteophyte severity. Exploratory correlation analyses showed that muscle contractile force was positively associated with selected subchondral bone parameters, whereas specific tetanic force was negatively associated with OARSI scores. HPLC-UV profiling putatively identified 54 compounds in XLGB, from which 14 representative compounds were selected for in vitro screening. Four compounds, icariin, 2″-O-rhamnosyl icariside II, loganic acid, and sweroside, promoted C2C12 myotube formation. Integration with previously reported anti-osteoarthritic compounds from XLGB identified icariin and 2″-O-rhamnosyl icariside II as candidate shared bioactive constituents potentially associated with the effects of XLGB in muscle and joint tissues. Conclusion XLGB produced distinct beneficial response patterns across tissues and doses in 37-week-old male SAMP8 mice with coexisting sarcopenia- and osteoarthritis-related phenotypes. Icariin and 2″-O-rhamnosyl icariside II were identified as candidate shared bioactive constituents, although their contributions to the in vivo effects of XLGB require further validation.Translational potential of this article: This study supports the utility of 37-week-old male SAMP8 mice for evaluating coexisting sarcopenia- and osteoarthritis-related phenotypes. The findings provide preclinical evidence that XLGB can beneficially influence both skeletal muscle dysfunction and OA-related joint degeneration. The tissue-specific dose responses highlight the need for dose optimization and further evaluation of efficacy, safety, and reproducibility in additional preclinical models before clinical translation.
Degenerative musculoskeletal diseases (DMDs) are a group of chronic conditions characterized by the progressive deterioration of tissue structure and function, primarily affecting the articular cartilage, bones, tendons, and ligaments. With global aging populations, the rising prevalence of these disorders presents a growing public health challenge. Current treatments for DMDs are limited by substantial drug side effects and restricted therapeutic efficacy. Gene therapy has emerged as a promising alternative for addressing these conditions. Nanoparticles are essential for overcoming intracellular and extracellular barriers in nucleic acid delivery. Recent technological advances have led to novel nanomaterials and strategies, which have enabled safer and more efficient gene therapy. This review comprehensively analyzes the role of nanoparticle delivery systems in enabling effective gene-based interventions for major DMDs. First, we analyze the main gene therapies for various DMDs. Next, we systematically summarize recent advances in nanocarrier platforms and delivery strategies targeting osteoporosis, osteoarthritis, intervertebral disc degeneration, and tendon diseases. Finally, we discuss key challenges and future directions, offering a roadmap to advance nanoparticle delivery therapeutics toward clinical impact. This synthesis uniquely bridges nanoparticle delivery design with disease-specific pathophysiology, providing strategic guidance for overcoming translational barriers through emerging technologies including AI-driven carrier optimization and organ-on-chip platforms.Across these diseases, no carrier is universally optimal: systemic bone delivery prioritizes circulation stability and cell-selective targeting, whereas local delivery to cartilage, intervertebral discs, and tendons requires a balance among tissue retention, matrix penetration, cellular uptake, and controlled release. Current evidence remains predominantly preclinical and frequently demonstrates tissue accumulation without fully establishing intact-cargo delivery, functional target engagement, long-term safety, or manufacturability. This review therefore links nanoparticle design to disease-specific barriers and identifies the evidence required for clinical translation.The Translational Potential of this Article.This review focuses on the clinical translational potential of nanoparticle-based delivery systems for gene therapy in degenerative musculoskeletal diseases (DMDs). Addressing the unique physiological and pathological barriers of specific musculoskeletal tissues (such as bone, cartilage, intervertebral discs, and tendons), this article systematically summarizes targeting and sustained-release strategies designed to enhance delivery efficiency and overcome tissue-specific obstacles. Furthermore, this study highlights future perspectives, including artificial intelligence (AI)-driven carrier optimization, organ-on-a-chip models, and multimodal combination therapies integrating biomaterials and cells. By addressing the limitations of conventional therapies that merely alleviate symptoms without reversing tissue degeneration, this review provides a robust theoretical foundation and a clear translational roadmap for the development of precise, safe, and long-lasting gene therapy regimens for DMDs.
