Immunohistochemical Study of Apoptosis of Lens Epithelial Cells in Human and Diabetic Rat Cataracts

Purpose: An immunohistochemical evalution of lens epithelial cell apoptosis.Methods: We performed terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assays on capsulotomy specimens (68 eyes in 53 patients) from patients who had undergone cataract surgery and an epithelium of diabetic cataracts in rats (144 eyes in 72 rats). The animal model of diabetic cataracts was prepared by injection of streptozotocin in three-week old rats. The rats were also examined using the proliferating cell nuclear antigen (PCNA) immunohistochemical staining method.Results: Although some TUNEL-positive cells were detected in capsulotomy specimens, we recognized little correlation between its distribution and morphological classification of cataracts. In the animal model of diabetic cataracts, TUNEL-positive cells were seen around the region where epithelial cells had accumulated. In the accumulated region, PCNA labeled cells undergoing DNA synthesis were also detected.Conclusion: These results suggest the possibility that apoptosis occurs in human lens epithelial cells and apoptosis and proliferation may be induced by factors such as hyperglycemia.