Lens Epithelial Cell Damage and Apoptosis in Atopic Cataract. Histopathological and Immunohistochemical Studies

Purpose: To elucidate the relationship between damage of lens epithelial cells and apoptotic cell death in patients with atopic cataract.Methods: Histopathological and immunohistochemical studies were carried out using anterior lens capsules obtained at surgery from 13 patients with atopic cataract and from 25 patients with senile cataract.Results: No specific histopathological findings were found in the lens epithelial cells in atopic cases. However, the frequency and severity of histopathological findings such as flattening, nuclear pyknosis, and loss of cells were more frequent and more severe in atopic cases than in senile cases. The terminal deoxynucleotidyl transferase (Tdt)-mediated dUTP-biotin nick end labelling (TUNEL) method revealed that the mean ratio of cells containing fragmented DNA to whole epithelial cells was almost the same in both atopic and senile cases. However, the mean ratio of Bax-positive cells was significantly higher in atopic cases (mean +/- standard deviation, 29.1 +/- 35.0%) than in senile cases (2.7+/-7.0%) (P<.05). The mean ratio of Bcl-2-positive cells was significantly lower in atopic cases (1.4+/-3.4%) than in senile cases (44.3+/-35.7%) (P<.05).Conclusion: These results suggest that apoptotic cell death may play an important role in the development of lens epithelial cell damage in atopic cataract.