This study aimed to investigate the therapeutic potential and anti-inflammatory mechanisms of tacrolimus (FK506) in moderate to severe dry eye by clinical, in vivo, and in vitro studies. We evaluated the effect of 0.1 % FK506 versus 0.1 % fluorometholone eye drops on patients with moderate to severe dry eye. Ocular surface disease index questionnaire (OSDI), tear breakup time (TBUT), corneal erosion, Schirmer's I test, and conjunctival impression cytology were measured at 2, 4, and 8 weeks. Tear samples from patients before and after FK506 treatment were subjected to proteomic analysis. The underlying mechanisms of FK506 were clarified using dry eye rat model and hypertonic-stimulated human corneal epithelial cells. Results demonstrated that FK506 showed transiently superior efficacy over fluorometholone in OSDI at week 2 (P = 0.041) and TBUT at week 4 (P = 0.001), despite both groups achieving significant improvements in all parameters from baseline to week 8 (P < 0.001). Tear proteomics revealed FK506-mediated modulation of autophagy-lysosomal pathway. FK506 improved ocular surface damage, reduced TNF-α and IL-1β, and upregulated LC3B II, TFEB, and LAMP1 protein expression, accompanied by reduced P62 in the rat cornea. In vitro, FK506 suppressed pro-inflammatory cytokines via enhanced autophagic flux, promoted TFEB nuclear translocation, restored lysosomal structural and functional integrity, while inhibited mTOR phosphorylation. Knockdown of TFEB reversed the FK506-mediated benefits. Overall, FK506 alleviates the symptoms and signs of moderate to severe dry eye by suppressing the inflammatory response in corneal epithelial cells. This therapeutic effect is mediated through the activation of the TFEB-driven autophagy-lysosomal pathway.

Background: Dry eye disease (DED) is often secondary to diabetes mellitus (DM).Purpose: This study is to explore the action of Wilms tumor 1-associated protein (WTAP) in DM-DED via lncRNA NEAT1 m6A methylation.Methods: DM-DED mouse models were treated with sh-WTAP/sh-NEAT1, followed by assessment of corneal epithelial damage/histopathological changes. HCE-2 cells were exposed to hyperosmotic conditions to establish in vitro DED models and treated with oe-NEAT1/sh-NEAT1/sh-WTAP/nigericin (an NLRP3 inflammasome inducer). Cell viability/apoptosis were evaluated by CCK-8/TUNEL. Levels of WTAP/NEAT1/inflammatory factors/NLRP3 inflammasome- and apoptosis-related markers were determined. m6A modification was examined by MeRIP-qPCR and NEAT1 stability was also detected.Results: DM-DED mice exhibited up-regulated WTAP/NEAT1 expression and severe corneal damage, whereas WTAP/NEAT1 knockdown alleviated inflammation/corneal damage. In hyperosmolarity-induced HCE-2 cells, NEAT1 aggravated inflammation and apoptosis, while NEAT1 knockdown suppressed NLRP3 inflammasome activation and ameliorated cell injury. Hyperosmolarity-induced WTAP expression increased m6A modification and NEAT1 mRNA stability. WTAP mediated m6A methylation of NEAT1 and NLRP3 inflammasome activation in DM-DED mice.

Background We present six patients who developed Candida keratitis postoperatively. The clinical features, diagnostic testing including in vivo confocal microscopy, and outcomes are presented. Methods Six patients who developed Candida keratitis following penetrating and endothelial keratoplasty, were referred to Tianjin Medical University Eye Hospital between 2018 to 2021.The diagnosis was established following cultures of either corneal scraping or biopsy. In vivo confocal microscopy examination was also performed to confirm the diagnosis and characterize the morphology, distribution and the depth of Candida spp. All patients were treated with topical voriconazole (VCZ) 1% and natamycin (NTM) 5%. Patients with mid/deep stromal keratitis or interface infection were treated additionally with intrastromal or interface VCZ irrigation (0.05 mg/0.1mL). Results The cultures of corneal scrapings (4 cases) or biopsies (2 cases) were all positive for Candida spp . In vivo confocal microscopy examination was positive for fungal elements in five of the six patients. The infection resolved in five of the six patients. The patients’ final uncorrected visual acuity (UCVA) ranged from hand movements (HM) to 20/80. Conclusion In vivo confocal microscopy is a useful non-invasive clinical technique for confirming the diagnosis of Candida keratitis. Intrastromal and interface irrigated VCZ injections are effective treatment options.

Purpose. To observe the decentration and tilt of implantable collamer lens (ICL) as well as possible visual effects postimplantation in primary iridociliary cysts. Methods. The present investigation was a retrospective cohort study. All 48 patients (91 eyes) who underwent ICL surgery at the Center of Refraction Surgery of Tianjin Medical University Eye Hospital between July 2018 and May 2020 were split into two groups based on the absence or presence of primary iridociliary cysts established by ultrasonic biological microscopy (UBM) examination. Intraocular pressure (IOP), corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), anterior chamber angle (ACA), anterior chamber volume (ACV), and anterior chamber depth (ACD) were recorded preoperatively and postoperatively at 1, 6, and 12 months. Additionally, we performed an analysis of the ICL vault, decentration, and tilt using a rotating Scheimpflug Oculus Pentacam camera system at 1, 6, and 12 months after surgery. Results. No serious complications were observed. Significant postoperative improvement (P < 0.05) of UDVA was established in the two studied groups; however, we did not observe statistically significant intergroup differences (P > 0.05) throughout the entire research period. In each group, the preoperative ACA, ACV, and ACD were statistically significantly reduced (P < 0.05), but no such decrease was established between their postoperative values (P > 0.05). We observed no statistical differences between both groups with regard to their values of IOP, ACA, ACV, ACD, ICL vault, ICL decentration, and tilt at 1, 6, and 12 months after surgery. Similarly, no statistically significant within-group correlation (P > 0.05) of the decentration of ICL and the tilt and the CDVA values was established. Conclusion. No postimplantation effect of ICL with a central hole on vision was established in myopia patients with primary iridociliary cysts, within certain limits of ICL decentration and tilt values.

Background: Phototherapeutic keratectomy (PTK) has been increasingly used to treat severe recurrent corneal erosion syndrome (RCES) patients who do not respond to other treatments. However, the efficacy and complication of each study are currently uncertain due to varying rates. Objectives: The objective of this study was to investigate the safety and efficacy of the PTK for recurrent corneal erosions. Methods: This article performed a systematic literature research in Cochrane, Embase, PubMed, Scopus, and the Web of Science for the literature on PTK treatment of RCES until December 20, 2022. The extracted data including recurrence rate and the adverse event rate were used for meta-analysis. Results: The recurrence rate was 18% (95% CI, 13%–24%) (129/700 eyes). Subgroup analysis showed that the RCE recurrence was 17% (95% CI, 9%–24%) after trauma and 22% (95% CI, 11%–32%) in the corneal dystrophy group. Treatment-related adverse events included subepithelial haze, hyperopic shift, and decrease of the best spectacle-corrected visual acuity. In this study, the incidence of these events was 13% (95% CI, 6%–21%), 20% (95% CI, 11%–28%), and 11% (95% CI, 5%–16%), respectively. Conclusions: PTK represented a valuable treatment option for patients with recurrent corneal erosions, especially those with traumatic injuries, which had minimal side effects.

Dry eye disease (DED) is widely believed that immune-related inflammation plays an important role in its pathogenesis. Tacrolimus (FK506) has a certain therapeutic effect on ocular inflammation in dry eye by inhibiting calcineurin or MAPK pathway in T lymphocytes, NF-κB pathway in ocular surface cells, and apoptosis of ocular surface cells. Currently, studies on the topical use of tacrolimus in the treatment of dry eye have focused on dry eye with systemic immune diseases, including chronic graft-versus-host disease, Sj?gren's syndrome, cicatoid pemphigoid, Steven-Johnson syndrome, etc. (Int Rev Ophthalmol, 2022, 46: 318-323)

BACKGROUND:Implantable collamer lens (ICL) surgery techniques are constantly progressing. The purpose of this study was to investigate the application effect of the modified technique and its impact on the change in corneal astigmatism in EVO-ICL surgery. METHODS:The analysis of retrospective cohort data included 153 eyes of 81 patients with myopia from July 2018 to May 2020. An EVO-ICL was inserted by modified surgical skills, including a single 3.0 mm corneal incision and no ophthalmic viscosurgical device (OVD) before the insertion of the ICL (modified technique group: 41 cases, 80 eyes) and standard procedure (standard technique group: 40 cases, 73 eyes). Early postoperative intraocular pressure (IOP) was monitored at 2 and 24 h. IOP, corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), vault, and anterior chamber depth (ACD) were measured 1, 6, and 12 months following the initial examination. The corneal endothelial cell density (ECD) was monitored at 6 and 12 months after the operation. Surgically induced astigmatism (SIA) in the total, anterior, and posterior corneal surfaces was analysed 1 month after the operation. RESULTS:No serious complications were detected. The two groups had no difference in visual outcomes, ICL vaults, or ACD at any time point (P > 0.05). Two hours postoperatively, IOP was significantly lower in the modified technique group (16.22 ± 2.22 vs. 18.37 ± 1.92 mmHg, P < 0.05) than in the standard technique group. IOP decreased gradually after 24 h to preoperative levels. The postoperative IOP remained stable over a 12-month period. The ECD at 6 and 12 months was not significantly different between the groups (P > 0.05). SIA in the total, anterior, and posterior corneal surfaces were assumed to have no clinically meaningful differences between groups at one month after operation (P > 0.05). CONCLUSIONS:The modified technique is efficient and safe, producing comparable visual and structural outcomes without adversely affecting ECD, and reduces fluctuations in IOP at the early postoperative stages. The auxiliary incision in the standard technique does not increase corneal SIA, which is also a factor to consider for inexperienced surgeons.

BACKGROUND:Mesenchymal stem cells (MSCs) are promising candidates for immunomodulatory therapy that are currently being tested in corneal allograft rejection. In this study, we tested the effects of Mesenchymal stem cells derived exosomes in the corneal allograft rejection model.METHODS:Mesenchymal stem cells derived exosomes (MSC-exo) were collected and characterized. Wistar-Lewis rat corneal allograft rejection models were established. PKH26 labeled exosomes were used for track experiment. Models were randomly separated into four groups and treated with graded doses of exosomes or same volumn of PBS. Corneal grafts were assessed for rejection degree using slit-lamp biomicroscopy. Grafts were examined histologically using hematoxylin-eosin (H-E) staining and immunohistochemically using antibodies against CD4, CD8 and CD25. A comprehensive graft mRNA gene expression array analysis was conducted and checked by real-time polymerase chain reaction (PCR).RESULTS:The nanovesicles obtained were expressing exosome specific protein markers CD9, CD63, CD81. The labeled exosomes could be detected in both cornea and anterior chamber two hours after injection.The 10 μg exosomes subconjunctival injection can effectively prolong graft survival time (MST 16.3 ± 2.5 days). 10 μg exosomes-treated group can inhibit the infiltration of CD4+ and CD25+ T cells. IFN-γ and CXCL11 levels were significantly decreased in grafts obtained from postoperative exosomes-treated rats when compared with controls.CONCLUSIONS:MSC-exo can cross biological barrier and play better role directly towards target tissue. MSC-exo can effectively prolong grafts survival time. Th1 signaling pathway was significantly inhibited in the exosomes treated group.

Fungal keratitis (FK) is a refractory disease that poses a serious threat to vision, with common risk factors like eye trauma, contact lens wearing, topical corticosteroids and antibiotic abuse. Nowadays, topical and systemic anti-fungal drugs and ocular surgeries are still the main therapeutic modalities. However, the pathogenesis of FK, especially the immunologic mechanism within it, has not yet been deeply clarified. A better understanding of the pathogenesis of FK is imperative for more effective therapies and prognosis. Meanwhile, the immune protection strategies are also urgently required to manage FK. This review highlights recent advances in the immunologic mechanism in the pathogenesis of FK, in hope of providing valuable reference information for more effective anti-fungal treatment.

Background: Mesenchymal stem cells (MSC) are promising candidates for immunomodulatory therapy that are currently being tested in corneal allograft rejection. In this study, we tested the effects of Mesenchymal stem cells derived exosomes in the corneal allograft rejection model.Methods: MSC derived exosomes were collected. Corneal grafts obtained from Wistar rats were transplanted into Lewis rat hosts. Hosts were then randomly separated into four groups and treated with previously harvested exosomes in different doses or PBS. Graft survival was clinically assessed using slit-lamp biomicroscopy and the median survival time (MST) was calculated. Grafts were examined histologically using hematoxylin-eosin (H-E) staining and immunohistochemically using antibodies against CD4. A comprehensive graft mRNA gene expression array analysis was conducted and checked by real-time polymerase chain reaction (PCR).Results: 1μg/ml exosomes subconjunctival injection prolonged graft survival time (MST 16.3±2.5 days). Exosomes-treated groups also showed suppression of inflammatory cell as well as CD4+, CD25+, CD45+ T cells infiltration in the allograft region. IFN-γ and CXCL11 levels were significantly decreased in grafts obtained from postoperative exosomes-treated rats when compared with controls.Conclusions: Subconjunctival injection of MSC derived exosomes in rats was effective in prolonging corneal allograft survival. Th1 signaling pathway was significantly inhibited in the exosomes treated group.

Rationale: Corneal transplantation is an effective treatment to corneal blindness. However, the immune rejection imperils corneal allograft survival. An interventional modality is urgently needed to inhibit immune rejection and promote allograft survival. In our previous study, subconjunctival injections of bone marrow-derived mesenchymal stem cells (BM-MSCs) into a rat model of corneal allograft rejection extended allograft survival for 2 d. In this study, we sought to generate IL-10-overexpressing BM-MSCs, aiming to boost the survival-promoting effects of BM-MSCs on corneal allografts and explore the molecular and cellular mechanisms underlying augmented protection. Methods: A population of IL-10-overexpressing BM-MSCs (designated as IL-10-BM-MSCs) were generated by lentivirus transduction and FACS purification. The self-renewal, multi-differentiation, and immunoinhibitory capabilities of IL-10-BM-MSCs were examined by conventional assays. The IL-10-BM-MSCs were subconjunctivally injected into the model of corneal allograft rejection, and the allografts were monitored on a daily basis. The expression profiling of long noncoding RNA (lncRNA) in the allografts was revealed by RNA sequencing and verified by quantitative real-time PCR. The infiltrating immune cell type predominantly upregulating the lncRNA expression was identified by RNAscope in situ hybridization. The function of the upregulated lncRNA was proved by loss- and gain-of-function experiments both in vivo and in vitro. Results: The IL-10-BM-MSCs possessed an enhanced immunoinhibitory capability and unabated self-renewal and multi-differentiation potentials as compared to plain BM-MSCs. The subconjunctivally injected IL-10-BM-MSCs reduced immune cell infiltration and doubled allograft survival time (20 d) as compared to IL-10 protein or plain BM-MSCs in the corneal allograft rejection model. Further, IL-10-BM-MSCs significantly upregulated lncRNA 003946 expression in CD68+ macrophages infiltrating corneal allografts. Silencing and overexpressing lncRNA 003946 in macrophage cultures abolished and mimicked the IL-10-BM-MSCs' suppressing effects on the macrophages' antigen presentation, respectively. In parallel, knocking down and overexpressing the lncRNA in vivo abrogated and simulated the survival-promoting effects of IL-10-BM-MSCs on corneal allografts, respectively. Conclusion: The remarkable protective effects of IL-10-BM-MSCs support further developing them into an effective interventional modality against corneal allograft rejection. IL-10-BM-MSCs promote corneal allograft survival mainly through upregulating a novel lncRNA expression in graft-infiltrating CD68+ macrophages. LncRNA, for the first time, is integrated into an IL-10-BM-MSC-driven immunomodulatory axis against the immune rejection to corneal allograft.

PURPOSE:To observe ocular surface changes in Type II diabetic patients with different disease durations and to understand the correlations between clinical parameters and diabetic durations.METHODS:In this cross-sectional, prospective study, 51 healthy controls and 91 patients with Type II diabetes were enrolled. The diabetics were divided into 3 subgroups according to the disease duration, including duration <10 y group, 10 to 20 y group, and ≥21 y group. All subjects underwent clinical ocular examinations, including lipid layer thickness (LLT), blinking rate, tear meniscus height (TMH), noninvasive tear film break-up time (NI-BUT), meibography, superficial punctate keratopathy (SPK) scoring, corneal sensitivity, and Schirmer I test. They were also evaluated using the standard patient evaluation of eye dryness (SPEED) questionnaire.RESULTS:SPEED score, meiboscore, SPK score, LLT, Schirmer I test, and corneal sensitivity differed significantly between the diabetic and healthy control groups. Further, SPEED score, Schirmer I test, corneal sensitivity, meiboscore, and blink rate significantly differed among the 3 diabetic subgroups and the control group. In diabetics, the SPEED score correlated with the SPK score, blink rate, TMH, and LLT; NI-BUT with TMH, LLT, and blink rate; TMH with the SPK score; Schirmer I test with the SPK score; and corneal sensitivity with the meiboscore. More importantly, the Schirmer I test, corneal sensitivity, and SPEED score negatively correlated with diabetic duration.CONCLUSION:Diabetic duration is an important factor that affects functions of the lacrimal functional unit in patients with Type II diabetes. The trends of changes in the ocular parameters vary along the course of diabetes.

目的 观察间充质干细胞来源外泌体(mesenchymal stems cells derived exosomes,MSCs-exo)对大鼠角膜移植排斥反应的抑制作用.方法 制作大鼠异体角膜移植排斥反应模型,随机分为4组:空白对照组、MSCs结膜下治疗组、PBS结膜下注射组、MSCs-exo结膜下治疗组.术后第3天开始裂隙灯下观察角膜植片排斥情况,并对MSCs-exo进行染色及示踪观察其结局.结果 空白对照组角膜植片存活时间为(9.67±0.56)d,MSCs结膜下治疗组为(12.33±0.76)d,PBS结膜下注射组为(9.50±0.34)d,MSCs-exo结膜下治疗组为(16.5±1.15)d.PBS结膜下注射组角膜植片存活时间较空白对照组差异无统计学意义(P＞0.05),而MSCs结膜下治疗组与MSCs-exo结膜下治疗组角膜植片存活时间较PBS结膜下注射组均明显延长(均为P＜0.05),MSCs-exo结膜下治疗组植片存活时间长于MSCs结膜下治疗组(P＜0.05).空白对照组大鼠免疫组织化学染色结果显示植片部分厚度比植床角膜厚度显著增厚,上皮层及基质层内见大量CD4+细胞聚集.而MSCs-exo结膜下治疗组植片中CD4+细胞比空白对照组明显减少.MSCs-exo结膜下注射后72 h时,仅有少量外泌体可在结膜下被观测到.进一步将观测时间前推至注射后24 h,发现大量外泌体存在于结膜下,而角膜组织和前房内也可见到外泌体的定位表达.结论 结膜下注射MSCs-exo可以显著延长角膜植片存活时间,外泌体治疗可能成为无细胞治疗的新方法.

Mesenchymal stem cells (MSCs) have been reported to promote long-term cellular and organ transplant acceptance due to their immunotherapeutic characteristics. Previous work from our lab using a rat allograft model has shown that systemic infusion of MSCs inhibited corneal allograft rejection and prolonged graft survival. Here, we further investigated the effects of local MSCs administration in the same animal model.

Objective To investigate the effect of mesenchymal stem cells (MSCs) combined with low-dose cyclosporin A ( CsA) on corneal transplantation rejection and its mechanism. Methods A fully allogeneic rat cornea transplant model (Wistar rats to Lewis rats) was created. Thirty-six model rats were divided into MSCs group, CsA group and MSCs+CsA group randomly by using the random number table method,with 12 rats for each group. In each group,six rats were used for the evalution of symptom observation and six for the assay of immune factor. Three days after corneal transplantation,slit lamp microscope was used to observe and record the vascularization,edema and opacity scores of corneal graft. After 18 days,spleen T helper cell(Th)1 and Th2 cytokines were measured by enzyme linked immunosorbent assay ( ELISA ). The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. This study protocol was approved by Ethic Committee of Tianjin Medical University Eye Hospital (No. TMUaMEC2017028). Results The survival time of corneal grafts in MSCs+CsA group was prolonged in comparison with the MSCs group and CsA group,with significant differences between them([21.3±3.9]days vs. (14.8±2.4)days; [21.3±3.9]days vs. [16.0±1.1]days) (P=0.003,0.004). Eighteen days after corneal transplantation,corneal opacity scores were 3.17±0.17, 3.00±0.00 and 2.17±0.17,corneal neovascularization scores were 2.67 ± 0.21,2.33 ± 0.21 and 1.83 ± 0.21, respectively in the MSCs group, CsA group and MSCs+ CsA group, showing significant differences among the three groups (F=15.500,P<0.01; F=4.524,P=0.029). The corneal opacity scores and corneal neovascularization scores in the MSCs+ CsA group were significantly lower than those in the MSCs group and CsA group(all at P<0.05). Interleukin(IL)-2,IL-4,IL-10,and interferon-γ (IFN-γ) concentrations were all significantly different among the MSCs group,CsA group and MSCs+ CsA group (F=15.000,12.810,10.720,17.960,all at P< 0.01). Compared with the MSCs group and CsA group,Th1 subsets cytokines IFN-γ and IL-2 concentrations in the MSCs+CsA group were significantly lower,and Th2 subsets cytokines IL-4 and IL-10 concentrations were significantly increased in the MSCs+CsA group in comparison with the MSCs group and CsA group ( all at P<0.05 ). Conclusions The combination of MSCs with low-dose CsA can effectively ameliorate immunological rejection by the modulation of the balance of Th1/Th2.

PURPOSE:To describe a case of interface fluid formation caused by uncontrollable intraocular pressure (IOP) 16 years after laser-assisted in situ keratomileusis (LASIK) surgery secondary to Posner Schlossman Syndrome (PSS).OBSERVATIONS:After trabeculectomy operation, IOP of the operative eye was back to normal, and the interface fluid refluxed over time.CONCLUSIONS:and importance: Interface Fluid Syndrome can be a potential lifelong complication after LASIK surgery. PSS patients post-LASIK require early IOP control.

Introduction of antigen into anterior chamber (AC) induces a deviant immune response termed anterior chamber-associated immune deviation (ACAID) that protects the eye from inflammatory destruction consequent to a systemic immune response. Mesenchymal stem cells (MSCs) can modulate a variety of immune responses. However, the effects of systemic administration of MSCs on ACAID have not been explored. In this study, C57BL/6 mice were inoculated with ovalbumin in the AC to induce ACAID, control group received AC injection of solvent alone. Immediately after the AC injection, the mice were injected through the tail vein with human Umbilical Cord-derived MSCs (hUC-MSC) or phosphate buffer saline. All animals were subcutaneously immunized with ovalbumin one week later. Delayed-type hypersensitivity assay was performed another week following immunization. The splenic monocytes were then isolated, cultured and stimulated with ovalbumin. Levels of IL-10, TGF-β, and IFN-γ in culture media were measured by ELISA. The frequencies of CD4(+)CD25(+)Foxp3(+) and CD8(+)Foxp3(+) regulatory T cells (Tregs) were determined by flow cytometry. The results showed that the AC inoculation of ovalbumin induced significantly less ear swelling than controls, confirming the establishment of ACAID. MSCs potentiated IL-10 and TGF-β production, further suppressed IFN-γ secretion from splenic monocytes in ACAID mice, and enhanced expansion of CD4(+)CD25(+)Foxp3(+) and CD8(+)Foxp3(+) Tregs isolated from the spleen of ACAID mice. Therefore, our study, for the first time, provides clear evidence that systemic administration of MSCs augments cytokine production and Treg expansion from ACAID spleens, which may contribute to promotion and maintenance of ACAID.

Mesenchymal stem cells (MSCs) are promising candidates for immunomodulatory therapy that are currently being tested in several organ transplant rejection models. In this study, we tested the immunomodulatory effects of MSC injection in a rat model of corneal allograft rejection. MSCs were isolated and cultured from bone marrow of Wistar rats. A rat corneal allograft rejection model was established using Wistar rats as donors and Lewis rats as recipients. Lewis rats were randomly separated into 12 groups and treated with MSCs alone or MSCs combined with Cyclosporin A (CsA) at different doses. In MSC-treated rats, the T cell response to ConA was evaluated, Th1/Th2 cytokines produced by T lymphocytes were measured, and the number of CD4+CD25+Foxp3+ regulatory T cells (Treg) was assessed. Results demonstrated that postoperative injection of MSCs prolonged graft survival time. MSCs significantly inhibited proliferation of pathogenic T cells in vitro and prevented T cell response in vivo (p < 0.05). Postoperative injection also reduced Th1 pro-inflammatory cytokines and elevated IL-4 cytokine secretion from T lymphocytes derived from cornea-transplanted rats. In addition, Tregs were upregulated by MSC treatment. Unexpectedly, the application of MSCs combined with low dose CsA therapy (1 mg/kg) accelerated graft rejection compared with postoperative MSC therapy alone. However, when 2 mg/kg CsA was given together with MSCs, graft survival was significantly prolonged. These results suggested that MSCs could exert therapeutic effect against corneal allograft rejection, and further investigation of combined MSC and CsA treatment be required as opposite effects were observed depending on CsA dose.

Objective To investigate the effect of mesenchymal stem cells(MSC) through phleboclysis on CD4+CD25+Foxp3+ regulatory T cells(Treg) in keratoplasty rejection in rats.Methods The dual eyes of Wistar rats(12 cases) were taken as donor graft,and the right eyes of Lewis rats(24 cases) as recipients.Twenty-four transplanted rats were divided into two groups,12 cases in each group.Rats in control group were given PBS,and MSC(5×106 mL-1,1 mL) were injected via the tail vein into the rats in experimental group.Clinical observation was performed at 4 days after operation by slit lamp.The rats were killed at 10 days after operation,and total RNA was isolated in mononuclear cells from spleen and lymph nodes,and RT-PCR was performed to measure the Foxp3 gene expression levels,and cells from the spleen were examined by flow cytometry to evaluate the rate of CD4+CD25+Foxp3+ Treg.Results The clinical score of the rats in experimental group(4.00±0.63)was significant lower than that of the rats in control group(5.67±1.37),there was statistical difference(P<0.05).The rate of CD4+CD25+Foxp3+ Treg in experimental group(6.25±0.35)% was higher than that in control group(5.45±0.38)%,there was statistical difference(P<0.05).The expression of Foxp3 mRNA in mononuclear cells from spleen and lymph nodes of the rats in experimental group(5.65±0.45) was significantly higher than that in control group(2.13±0.74),there was statistical difference(P<0.05).Conclusion MSC can effectively prevent and ameliorate immunological rejection through increasing the proportion of CD4+CD25+Foxp3+ Treg to modulate anterior chamber associated immune deviation.

OBJECTIVETo investigate the effect of mesenchymal stem cells (MSC) on keratoplasty rejection in a rat mode.METHODSMSC from bone marrow of Wistar rats was cultured. Corneas of Wistar rats (donors) were transplanted to Lewis rats (recipients). Transplanted rats were randomly divided into A, B, C three groups. Rats in group B were injected with MSC suspended in PBS via the tail vein continually for three days before the surgery, while rats in group C accepted similar MSC transplantation after the surgery. The rats in group A were given the same volume of PBS. Grafts were scored for corneal transparency, edema and extent of neovascularization by slit lamp observation. Expressions of CD(4), CD(8), CD(25) and CD(45) in corneas 10 days after transplantation were examined by immunohistochemistry.RESULTSThe survival time of the corneal grafts in group C [(9.9 ± 0.69) d] was significantly prolonged compared with that of the group A and group B [(11.83 ± 0.54), (16.89 ± 1.91) d] (F = 5.732, P = 0.001, 0.019). Expression level of CD(4), CD(8), CD(25) of the corneal grafts in group C was lower than that of group A and group B (t = 2.477, 2.359, 2.445, P = 0.024, 0.042, 0.030).CONCLUSIONPost-operative injection of MSCs could inhibit keratoplasty rejection and prolong the corneal allografts survival in a rat model.