[Cell cycle block and apoptosis in rabbit lens epithelial cells induced by hydroxycamptothecine]

To study the cell cycle block and apoptosis induced by hydroxycamptothecine (HCPT) in cultured rabbit lens epithelial cells (RLECs) and its affect on the gene expression of fas/fas-L in RLECs.

Flow cytometry was used to examine HCPT-induced cell cycle block in cultured RLECs. We observed cell morphological changes with light microscope and electron microscope. Apoptosis was detected by terminal deoxyribose transferase-mediated deoxy-uridine triphosphate nick end labeling (TUNEL) assay. The TUNEL assay was performed following the manufacturer's instruction of in situ cell death detection. Expression of Fas and Fas-L was estimated by immunohistochemical staining.

The flow cytometric analysis showed that the HCPT induced cell cycle block was at S phase. The ratio of nucleus and cytoplasm was increased. The electron microscopic examinations demonstrated that the HCPT initiated apoptosis with typical morphological features. The apoptosis of RLECs treated with HCPT was observed by TUNEL assay, and the number of the cells with apoptosis was increased with the increase of the HCPT concentration. The HCPT did not affect the gene expression of Fas/FasL.

HCPT not only induces mitotic block but also induces apoptosis of RLECs which is not mediated by the Fas/FasL signaling pathway.