PURPOSE. To characterize the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in human cortical cataract and to determine whether there is a correlation with the localization of cortical cataract. To evaluate the expression and activity of MMPs and TIMPs after cytokine and UV- B exposure in a human lens epithelial cell line. METHODS. Twenty- eight human donor eyes with cortical cataract and 21 normal human donor eyes were photographed. Thirteen cortical cataract and six normal lenses were immunohistochemically analyzed for MMP- 1, - 2,- 3, and- 9 and TIMP- 1,- 2, and- 3. Twelve fresh cortical cataract and 12 normal lenses were divided into quadrants to quantify, by ELISA, the expression of MMP- 1,- 2,- 3, and- 9 and TIMP- 1. Three fresh cortical cataract and three control lenses were assessed for MMP- 1,- 2, and- 9 activity by SDS- PAGE zy- mography. Human lens epithelial cells (HLE- SRA- 01/04) were exposed to proinflammatory cytokines and UV- B radiation to determine the protein expression profiles of MMP- 1,- 2,- 3, and- 9 and TIMP- 1 and- 2. RESULTS. Immunohistochemical analysis revealed specific localization of MMP- 1 within lens epithelium and cortical lens fibers of cortical cataract. Normal lenses had equally low MMP- 1,- 2,- 3, and- 9 and TIMP- 1, - 2, and- 3 immunoreactivity, expression, and activity in all lens quadrants. IL- 1 and TNF- α upregulated the expression of MMP- 2,- 3, and- 9, and UV- B upregulated the expression of MMP- 1 in the SRA- 01/04 HLE cell line. CONCLUSIONS. This is the first study to localize the expression of MMP- 1 in cataracts with clinically observed opacification in vivo and to examine the expression induced by UV- B, in vitro.
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