背景 细胞周期调节不平衡可诱发增生性玻璃体视网膜病变(PVR),研究周期蛋白依赖性激酶(CDK)及其抑制因子(CKI)对PVR形成过程中视网膜色素上皮(RPE)细胞和成纤维细胞病理增生过程中细胞周期的调控对PVR的防治具有重要意义. 目的 研究CKI p21和p27在不同发育阶段正常兔视网膜中的表达规律,探讨p21和p27表达与细胞生长的关系. 方法 按照兔龄将9只新西兰白兔分为10周龄组、20周龄组和30周龄组,每组3只.实验兔处死后取出双眼分别用于p21和p27在转录水平和翻译水平表达的检测.分离视网膜组织,采用real-time PCR和Western blot法分别检测不同周龄兔视网膜中p21和p27mRNA及其蛋白的表达变化.结果 10周龄组、20周龄组和30周龄组兔视网膜组织中p21 mRNA的相对表达量分别为1.631 ±0.063、1.506±0.012和1.585±0.015,p27 mRNA的相对表达量分别为1.581±0.048、1.470±0.012和1.490±0.013,总体比较差异均有统计学意义(p21:F=9.311,P=0.014;p27:F=12.360,P=0.007),其中10周龄组和30周龄组兔视网膜组织中p21和p27 mRNA的表达量均明显高于20周龄组,差异均有统计学意义(均P＜0.05).10周龄组、20周龄组和30周龄组兔视网膜组织中p21蛋白的相对表达量分别为0.675±0.061、0.089±0.001和0.200±0.007,p27蛋白的相对表达量分别为0.928±0.019、0.183±0.005和0.576±0.089,总体比较差异均有统计学意义(p21:F=228.905,P＜0.001;p27:F=148.957,P＜0.001),其中10周龄组和30周龄组兔视网膜组织中p21和p27蛋白的表达量均明显高于20周龄组,差异均有统计学意义(均P＜0.01).兔视网膜中p21与p27间mRNA及蛋白的相对表达量均呈正相关(mRNA:r=0.906,P＜0.01;蛋白:r=0.913,P＜0.01).结论 p21和p27在生长发育期的兔视网膜中表达量升高,随着生长过程变缓其表达量降低,之后随着视网膜组织老年性变化发生病理性表达增加,在细胞周期调控过程中可能起着平衡作用.%Background The imbalance of cell cycle regulation results in proliferative vitreoretinopathy (PVR).Studing the effects of cyclin dependent kinase (CDK) and CDK inhibitor (CKI) on the cell cycle regulation of retinal pigment epithelial (RPE) cells and fibroblasts in PVR formation is of important significance.Objective This study was to investigate the expressing trend of p21 ,p27 and CDK inhibitors in retinas of different ages of rabbits and explore the relationship between p21 or p27 and cell growth.Methods Nine clean New Zealand rabbits were assigned to 10-week group,20-week group and 30-week group according to the age and 3 rabbits for each.The eyeballs were enucleated binocularly after the animals were sacrificed and retinas were isolated.Real-time PCR and Western blot were employed to detect the expressions of p21 and p27 mRNA and their proteins in retinas of the rabbits.The use and care of the animals followed the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Committee.Results The relative expressing levels of p21 mRNA were 1.631±0.063,1.506±0.012 and 1.585 ±0.015, and those of p27 m RNA were 1.581 ± 0.048,1.470 ± 0.012 and 1.490 ±0.013 in the 10-week group,20-week group and 30-week group, respectively, showing significant differences among the groups (p21 mRNA: F=9.311,P=0.014;p27 mRNA: F=12.360, P=0.007) , and the p21 and p27 mRNA expressing levels were significantly higher in the 10-week group and 30-week group than those in the 20-week group (all at P＜ 0.05).The expressing levels of p21 protein were 0.675 ± 0.061,0.089 ±0.001 and 0.200 ± 0.007, and those of p27 protein were 0.928±0.019,0.183±0.005 and 0.576±0.089 in the 10-week group,20-week group and 30-week group, respectively, with remarkable differences among the groups (p21 : F =228.905, P＜0.001;p27 : F =148.957,P＜0.001), and the expressions were significantly raised in the 10-week group and 30-week group in comparison with the 20-week group (all at P＜0.01).Significantly positive correlations were found in the expressing levels of p21 and p27 both in transcriptional and protein levels (mRNA : r =0.906, P＜0.01;protein : r =0.913, P＜0.01).Conclusions The expressions of p21 and p27 up-regulate in the retinas of developing stage of rabbits but gradually reduce with adultness.However, p21 and p27 levels appear to be increasingly raised with aging of the rabbits.It is implied that p21 and p27 play a balancing role in the process of cycle regulation in retina cells.
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