形觉剥夺对小鸡后极部巩膜MMP-2基因表达的影响

Effect of form deprivation on levels of matrix metalloproteinase-2 expression in the posterior sclera of chicks

目的:研究形觉剥夺对小鸡后极部巩膜MMP-2基因表达影响的动态性变化,以揭示FDM巩膜重塑的发生机制。方法:1d龄来亨雏鸡进行单眼遮盖以制备形觉剥夺性近视眼(FDM)动物模型,按遮盖时间不同分为FDM4,7,14,21,30d5组,对侧眼作为自身对照组。随机选取同龄、非遮盖小鸡作为正常对照组,每组10只。采用明胶酶谱法、逆转录聚合酶链反应(RT-PCR)一步法、免疫组化法分别检测各组小鸡后极部巩膜明胶酶活性、mRNA及蛋白质表达。结果:FDM组后极部巩膜MMP-2酶活性与mR-NA水平显著增高,与相应自身对照组、正常对照组比较差别均有统计学意义(P<0.01);随遮盖时间延长后极部巩膜MMP-2酶活性、mRNA水平逐渐增高,尤其在被剥夺4～14d最明显,21d达高峰,其后稍下降,但仍维持于较高水平。FDM组组间差别有统计学意义(P<0.01)。上述改变与免疫组化结果一致。结论:形觉剥夺可明显促进小鸡后极部巩膜MMP-2酶活性表达,其中基因表达转录调节参与FDM后极部巩膜MMP-2酶活性调控。

AIM： To evaluate the effect of form deprivation on levels of matrix metalloproteinase-2 （MMP-2） gene expression in the posterior sclera of chicks. METHODS： Fifty 1-day-old chicks were monocularly deprived to establish the animal model of form-deprivation myopia （FDM）. According to the duration of form deprivation, the experimental chicks were divided randomly and equivalently into 5 groups： FDM 3,7,14,21,30d groups. Meanwhile the fellow eyes of deprived chicks were used as self-control and chicks of same days＇old were chosen randomly as normal control groups. One step reverse transcriptiontase-polymerase chain reaction （RT-PCR） and histochemistry were performed to measure the expression of mRNA and proor active protein of MMP-2 respec- tively. Gelatin enzymography was used to determine the level of activity of MMP-2 in the posterior sclera of these experimental eyes. RESULTS： Compared with normal and self-control groups, the levels of mRNA and activity of MMP-2 in FDM groups were significantly higher （P〈0.01）. With longer time of monocular deprivation the mRNA level and activity of MMP-2 increased gradually, and reached the top from 4d to 14d, afterwards it declined, but still remained high level. The difference among the FDM groups was statistically different （P〈0.01）. The above changes were correlated with the results of histochemistry. CONCLUSION： FDM can induce the increased expression of MMP-2 activity in the posterior sclera of chicks, which is modulated at least partly by transcriptional level of its gene expression.