不同类型年龄相关性白内障晶状体上皮细胞衰老标记蛋白30的表达及与细胞凋亡的关系

摘要

背景 随着人口的老龄化,白内障的发病率逐年上升,研究表明,衰老标记蛋白30( SMP-30)与白内障的发生发展关系密切. 目的 了解不同类型白内障晶状体上皮细胞( LECs)中SMP-30的表达及LECs的凋亡情况,探讨不同类型年龄相关性白内障的发病机制. 方法 收集2010年3-10月在武汉大学中南医院眼科行白内障超声乳化摘出术的年龄相关性皮质性白内障59例80眼和核性白内障53例70眼,2个组患者年龄匹配(P＞0.05).白内障手术中环形撕取晶状体前囊膜,应用免疫组织化学法和实时荧光定量聚合酶链反应( real-time PCR)技术分别定性、定量检测SMP-30蛋白及其mRNA在2个组白内障LECs中的表达.用TUNEL标记法观察LECs的凋亡情况,对比分析两种类型白内障晶状体前囊膜中SMP-30的表达及细胞凋亡的差异.结果 免疫组织化学法检测表明,SMP-30主要表达于晶状体囊膜的细胞质中,在晶状体囊膜中央部表达较弱,越近周边表达越强,差异均有统计学意义(核性:45.21±2.79 vs 76.42±11.21,P=0.042；皮质性:108.32±4.32 vs 206.34±15.67,P=0.037).核性白内障LECs中SMP-30 mRNA的表达少于皮质性,差异有统计学意义(60.02±9.08 vs 157.33±13.01,P=0.034).TUNEL染色显示,2个组白内障LECs凋亡百分率中央部明显高于周边部,差异均有统计学意义(核性:19.34％±0.11％vs 8.32％±0.57％,P=0.025;皮质性:42.07％±0.86％vs 13.55％±0.64％,P=0.010),细胞凋亡百分率低于皮质性,差异有统计学意义(14.05％±0.22％vs 27.70％±0.81％,P=0.007). 结论 两种类型年龄相关性白内障的发生均与LECs凋亡有关,SMP-30的表达与其密切相关.%Background Following the accelerated speed of population aging in China,the incidence of cataract is rising gradually.Researches indicated that senescenee marker protein-30 ( SMP-30 ) is closely associated with the occurring and developing of cataract. Objective This study was to investigate the expression of SMP-30 in human lens epithelial cells(LECs) of age-related cataract and study the relationship between SMP-30 and apoptosis.Methods Capsulotomy was performed on 80 eyes of 59 patients with simple cortex age-related cataract and 70 eyes of 53 age-matched patients with nucleus age-related cataract.The anterior capsular specimens were obtained by circularly capsulorhexis during the operation.Expressions of the SMP-30 protein and mRNA in the LECs of two types of cataract were detected using immunochemistry and real-time PCR respectively.Apoptosis of the LECs was assayed by TUNEL.The differences of expression of SMP-30 and apoptosis were compared between the two types of cataract.Results Immunochemistry showed that SMP-30 was expressed in cytoplasm of LECs.The expression intensity of SMP-30 was higher in the center zone compared with periphery zone.The apoptosis rate of LECs was significantly higher in the center of the anterior capsule than the periphery in both two types of cataract ( nucleus cataract:19.34％±0.11％ vs 8.32 ％ ± 0.57 ％,P =0.025 ; cortex cataract:42.07 ％ ± 0.86 ％ vs 13.55 ％ ± 0.64 ％,P =0.010 ).The expression amount of SMP-30 mRNA was lower at the periphery than the center of lens in both two types of cataract (nucleus cataract:45.21±2.79 vs 76.42±11.21,P=0.042 ;cortex cataract:108.32±4.32 vs 206.34±15.67,P=0.037 ),and that of nucleus cataract was significantly lower than cortex cataract (60.02±9.08 vs 157.33 ± 13.01,P =0.034),and the apoptosis rate of LECs was declined in the nucleus cataract group compared with the cortex cataract group ( 14.05％ ±0.22％ vs 27.70％ ±0.81％,P =0.007 ). Conclusions LECs apoptosis exists in age-related cataract.SMP-30 probably plays an important role in the formation of cataract.