胶原相关整合素β1在形觉剥夺性近视诱导及恢复期中调节巩膜重塑作用的研究

Abstract

目的：探讨豚鼠形觉剥夺性近视(form-deprivation myopia，FDM)模型中巩膜胶原相关整合素β1在巩膜重塑中的作用。方法：2~3周龄三色豚鼠128只，分为实验组(n = 64)和正常对照组(n = 64)。实验组采用头套法遮盖右眼进行形觉剥夺，左眼则为自身对照，正常对照组双眼不予任何处理。实验组依据形觉剥夺l周、2周、4周不同时间建立不同近视诱导和进展过程中的动物模型。并通过对形觉剥夺4周动物去除遮盖物，依据去遮盖时间l天、3天、5天、7天及14天建立不同时间点FDM恢复期的动物模型。在各个时间点对各组动物分别进行检测：带状光检影测量屈光度值；游标卡尺测量眼轴长度；苏木素–伊红(HE)染色观察后极部巩膜组织形态学变化；实时荧光定量聚合酶链反应(QRT-PCR)、免疫组织化学方法检测后极部巩膜胶原相关整合素β1 mRNA及蛋白表达情况。结果：形觉剥夺2周、4周后，实验组右眼分别诱导出(−3.00 ± 0.50) D及(−5.50 ± 1.08) D的相对近视，眼轴分别拉长(0.22 ± 0.06) mm及(0.49 ± 0.11) mm，与自身对照组及正常对照组相比，组间差异均有统计学意义(P均 0.05)。去遮盖后，豚鼠右眼重新正视化，与自身对照、正常对照眼相比，去遮盖7天时屈光度差值差异无显著性(P > 0.05)；右眼眼轴长度缩短，14天时眼轴长度差值差异无显著性(P > 0.05)。巩膜形态学观察见形觉剥夺性近视眼豚鼠后极部巩膜胶原纤维排列紊乱，巩膜变薄；QRT-PCR及免疫组织化学染色显示，实验组右眼形觉剥夺l周后眼球后部巩膜整合素β1 mRNA及蛋白表达明显减少，差异有统计学意义(P 0.05)。自身对照组的上述所有检测指标与正常对照组相比，均无明显差异(P > 0.05)。结论：单眼遮盖可以导致FDM的发生；2~3周龄豚鼠去除形觉剥夺后可以重新进行正视化，伴随眼轴长度缩短；去遮盖7天内为眼生物学参数恢复的主要时期；豚鼠形觉剥夺时，后极部巩膜整合素β1表达减少，去遮盖后表达上调，提示整合素β1可能参与了形觉剥夺性近视的发生，其影响巩膜重塑的机制有待进一步研究。 Objective: To investigate the role of collagen-binding integrin β1 in sclera remodeling process of the guinea pig form-deprivation myopia (FDM). Methods: 128 young guinea pigs, aged 2 to 3 weeks, were randomized into experimental group (n = 64) and normal control group (n = 64). FDM models were monocular deprived by placement of a facemask over the right eye in the experimental group, and the fellow eyes served as the contralateral control eyes. The guinea pigs in the normal control group were raised with both eyes untreated. The FDM eyes were monocular deprived for 1, 2 and 4 weeks, and recovered 1, 3, 5, 7, 14 days after occluding for 4 weeks. Optical measurements and axial length were accomplished at all of the time points. The histological analysis was applied to assess the posterior sclera changes, and immunohistochemical staining and quantitative real-time PCR (QRT-PCR) were applied to investigate the expression of integrin β1 protein and mRNA. Results: After 2 and 4 weeks, compared with the fellow eyes and the normal control group, the refraction diopter of the experimental group was (−3.00 ± 0.50) D and (−5.50 ± 1.08) D, and the axial length elongated (0.22 ± 0.06) mm and (0.49 ± 0.11) mm, showing significant differences respectively (P 0.05). After re-exposure, the right eyes of guinea pigs in the experimental group experienced re-normalization and the refraction was rapidly recovered in the initial 7 days (P > 0.05); the axial length gradually shortened, and it was statistically non-significant after 14-day recovery (P > 0.05). The morphological observation of sclera found that the posterior sclera collagen fiber arrangement of guinea pigs with FDM was disordered and the sclera became thinner. Scleral integrin β1 mRNA and protein expression in FDM eyes were significantly lower than those in the controls after monocular deprived 1 week (P 0.05). The difference of all the above statistics between contralateral control eyes and the normal control group was not remarkable (P > 0.05). Conclusion: Form-deprivation myopia was able to be induced by monocular covering. Guinea pigs aged 2 to 3 weeks with form-deprivation can experience re-normalization after recovery, along with the shortening of the axial length. The main recovery stage of ocular biometric parameters was in the initial 7 days. The expression of integrin β1 in FDM sclera was found to be lower, but could be restored during the recovery period. This suggests that collagen- binding integrin β1 may be involved in the pathogenesis of myopia, and further study needs to be done on the mechanism of the scleral remodeling in myopia.