The expression of senescenee markern protein-30 in different types of age-related cataracts and its relation to apoptosis of lens epithelial cell

Abstract

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. Key words: Senescenee markern protein-30 ; Cataract ; Lens epithelial cell; Apoptosis