摘要
背景 间充质干细胞（MSCs）已用于多种器官移植抗排斥反应的基础和临床研究.我们先前的研究表明,鼠尾静脉注射MSCs可延长大鼠角膜植片的存活时间,但治疗时MSCs的需求量较大且存在一定的全身不良反应.眼局部应用MSCs是否能够替代角膜移植排斥反应的全身治疗尚不清楚. 目的 探讨结膜下注射骨髓MSCs对大鼠角膜移植排斥反应的作用.方法 从清洁级Wistar大鼠股骨和胫骨骨髓中分离获得MSCs进行培养和传代,以体外成骨细胞分化和脂肪细胞分化法进行鉴定,取第3代MSCs用于实验.将20只Wistar大鼠双眼角膜作为角膜供体植片,40只Lewis大鼠右眼作为受体植床,行同种异体穿透角膜移植术.应用随机数字表法将40只受体大鼠分为PBS对照组和MSCs治疗组,另取6只正常Lewis大鼠作为正常对照组.MSCs治疗组大鼠分别于角膜移植术后即刻和第3天结膜下注射含2＆#215;106 MSCs的PBS 0.1 ml,PBS对照组大鼠以同样的方法仅给予等容积PBS.各组大鼠术后每天裂隙灯显微镜下观察角膜植片的混浊、水肿和新生血管情况,并按角膜植片排斥反应标准进行评分.于术后第10天分别处死PBS对照组和MSCs治疗组各12只大鼠,取出术眼角膜组织,采用实时荧光定量PCR法检测Th1细胞相关炎性因子γ干扰素（IFN-γ）mRNA和白细胞介素-2（IL-2）mRNA及Th2细胞相关炎性因子IL-4 mRNA和IL-10 mRNA在角膜中的相对表达量;采用ELISA法检测角膜组织中Th2细胞相关因子IL-4和IL-10蛋白的质量浓度. 结果 培养的细胞生长良好,成骨细胞分化的细胞茜素红染色呈橘黄色,脂肪细胞分化的细胞油红O染色呈红色,证实为MSCs.角膜移植术后MSCs治疗组角膜植片存活时间为（11.8±1.6）d,长于PBS对照组的（9.6±1.4）d,差异有统计学意义（P=0.004）;MSCs治疗组大鼠角膜植片中IFN-γmRNA、IL-2 mRNA的相对表达量较PBS对照组下降,但2个组间差异均无统计学意义（均P＞0.05）,但IL-4 mRNA和IL-10 mRNA相对表达量明显高于PBS对照组,差异均有统计学意义（均P=0.00）.正常对照组、PBS对照组和MSCs治疗组大鼠角膜植片中IL-10蛋白质量浓度分别为（22.74±7.06）、（68.40±12.83）和（215.41±44.66） pg/ml,3个组间总体比较差异有统计学意义（F=55.06,P=0.00）,且MSCs治疗组大鼠植片中IL-10蛋白质量浓度明显高于PBS对照组及正常对照组,差异均有统计学意义（均P＜0.05）.结论 结膜下注射MSCs可以延长大鼠异体穿透角膜移植术后植片的存活时间,这一作用可能是通过调节Th 1/Th2平衡,特别是上调Th2细胞因子而介导的.
Background Mesenchymal stem cells （MSCs） have been applied in basic and clinical researches of organ transplantation.Our previous study showed that intravenous injection of MSCs prolonged corneal allograft survival in rat.However,the effect of local administration of MSCs on corneal allograft rejection remains unclear.Objective The aim of this study was to investigate the effect of subconjunctival injection of MSCs on corneal allograft rejection in rat model of keratoplasty.Methods MSCs were isolated and cultured from femur and tibia bone marrow of clean Wistar rats,and then the cells were identified by induced differentiation of osteoblast and adipocyte.The third generation of MSCs was used in subsequent experiment.Allogenic penetrating keratoplasty was performed with the bilateral corneas of 20 Wistar rats as donor grafts and the right eyes of 40 Lewis rats as recipients.PBS 0.1 ml containing 2 ＆#215; 106 MSCs and 0.1 ml PBS only was subconjunctivally injected immediately and postoperative 3 days respectively in randomized two groups,and another 6 normal Lewis rats served as the normal control group.Corneal rejection response was evaluated under the slit lamp after surgery based corneal opacity,edema and neovascularization,and the grafts were scored according to the criteria of Larkin.The corneal samples were extracted from 12 rats of the PBS control group and the MSCs group separately 10 days after surgery.The relative expressions of Th1 cytokines （interferon-γ [IFN-γ] mRNA and interleukin-2 [IL-2] mRNA） and Th2 cytokines （IL-4 mRNA and IL-10 mRNA） were detected by real-time quantitative PCR.Protein levels of IL-4 and IL-10 proteins in the corneas were assayed by ELISA.All experimental protocols involving rats were approved by the laboratory animal care and use committee of the Tianjin Medical University and treated with the ARVO statement for the use of animals in ophthalmic and vision research.Results The cells grew well with the orange stain for alizarin red in differentiated the osteoblasts and red stain for Oil red O in differentiated adipocytes.The survival time of corneal graft in the MSCs group was （11.8±1.6） days,it was significantly longer than （9.6±1.4） days in the PBS control group （P=0.004）.The levels of IL-4 mRNA and IL-10 mRNA in the MSCs group were significantly higher than those in the PBS control group （both at P =0.00）;while the levels of IFN-γ mRNA and IL-2 mRNA were not significantly different between the groups （both at P〉0.05）.The IL-10 protein contents were （22.74 ±7.06）,（68.40±12.83） and （215.41 ±44.66）pg/ml in the normal control group,PBS control group and MSCs group,showing significant difference among the three groups （F =55.06,P =0.00） and a significant increase in the MSCs group compared with the PBS control group and the normal control group （both at P 〈 0.05）.Conclusions Subconjunctival injection of MSCs prolongs the survival time of cornea allograft in penetrating keratoplasty probably by modulating the balance between Th1 and Th2 cytokines,especially by up-regulating Th2 cytokines.
出处
《中华实验眼科杂志》
CAS
CSCD
北大核心
2015年第5期440-445,共6页
Chinese Journal Of Experimental Ophthalmology
基金
国家自然科学基金项目（81270975）
