OBJECTIVE

To observe oxidative cataract inhibition of PD150606 by studying the opacity of the lens, the variation of protein and cells, and by further studying the role of calpains in the mechanism of oxidative cataract.

METHODS

Rat lenses were cultured in vitro with H(2)O(2) and PD150606. The lenses were observed under the microscope. Simultaneously, photograph analysis was performed in order to detect the variation of opacity; the proportion of WSP was determined by the method of Lowry; the number of apoptotic lens epithelial cells (LEC) was measured by flow cytometry; the expression of Caspase 3 in LEC was determined by SAS-PAGE electrophoresis and immunoblotting.

RESULTS

Opacity of lens was enhanced in 24 hours when cultured with H(2)O(2) and PD150606. There were significant differences of relative gray scale between H(2)O(2)-induced and control group at 6, 12 and 24 hours (P < 0.05), significant differences of the proportion of WSP between H(2)O(2)-induced and control group at 12 and 24 hours (P < 0.01), significant differences of the number of apoptotic LEC at 6, 12 and 24 hours (P < 0.01) and significant differences of expression of Caspase 3 at 6, 12 and 24 hours (P = 0.000, 0.005, 0.004).

CONCLUSION

PD150606, an inhibitor of calpain, can inhibit H(2)O(2)-induced opacity of lens, proteolysis and apoptosis of LEC partially. The activated calpains can induce degradation of crystallins and apoptosis of LEC, which may play a role in the mechanism of oxidative cataract. Caspase 3-dependent pathway may contribute to apoptosis of LEC induced by calpains.