Expression of osteonectin in lens epithelium cells in age-related cataract

Abstract

To study the expression of osteonectin (also called secreted protein acidic and rich in cysteine, SPARC) in the lens epithelium cells in cortex cataract and nucleus cataract. This is an experimental research. Forty-five capsulotomy specimens were obtained from 33 patients suffered form pure cortex or/and nucleus cataracts and classified as nucleus group and cortex group, between May to July of 2010. Immunohistochemistry was used to detect the SPARC, which was analyzed by gray value. TUNEL was used to examine the apoptosis of lens epithelium cell. The difference of SPARC expression and apoptosis rate between these two groups was analyzed by LSD-t. Twenty specimens were studied with immunohistochemistry (C/N = 8/12), and 25 specimens studied by TUNEL test (C/N = 9/16). Expression of SPARC in the cortex group was significantly less than that in the nucleus group (peripheral region: t = 2.827, P < 0.05; central region: t = 2.264, P < 0.05). Expression of SPARC in the central region was significantly less than that in the peripheral region (peripheral region: t = 3.473, P < 0.05; central region: t = 2.771, P < 0.05). Apoptosis rate in the nucleus group was significantly lower than the cortex group (nucleus group: t = 2.364, P < 0.05; cortex group: t = 2.723, P < 0.05). Apoptosis rate in peripheral region was significantly less than that in central region (nucleus group: t = 2.771, P < 0.05; cortex group: t = 2.473, P < 0.05). The expression of SPARC is different between nucleus cataract and cortex cataract and also different between central and peripheral regions. The expression of SPARC is related with apoptosis of lens capsule epithelium cells.