Priming mechanism for the apoptosis of corneal endothelial cells induced by high pressure / 眼科新进展

ABSTRACT

Objective To investigate the initiation pathway of corneal endothelial cell apoptosis induced by high-pression.Methods Primary rabbit corneal endothelial cells were identified by immunohistochemistry and cultured under high pressure 50 mmHg (1 kPa =7.5 mmHg) for 1 h,2 h,24 h,respectively,while cells cultured under the normal pressure 15 mmHg served as the normal pression group.In addition,the first generation of rabbits corneal endothelial ceils with 70％ to 80％ fusion were pretreated with 10-6 mol · L-1 anti-Caspase 8 and anti-Caspase 9 for lh,followed by 50 mmHg pression for the treatment of the cells;while cells cultured with no inhibitor in the same pression served as the control group.Then the expression of P53 and Bcl-2 protein was detected by Western blot,and cytochrome C in rabbit corneal endothelial cells was determined by immunofluorescence staining in all groups.Results The expression levels of P53 in the 50 mmHg group were 0.651 +0.007,0.805 ±0.006 and 0.839 ±0.011 after 1 h,2 h,24 h high-pression respectively,which were significantly higher than those in the normal pressure group (0.033 ± 0.004),and the difference approached statistical significance (all P ＜ 0.01).The expression of P53 protein in corneal endothelial cells gradually increased as time went on,and the difference was statistically significant between each two time-points (all P ＜ 0.01).Moreover,the expression of Bcl-2 in the 50 mmHg pressure group was 0.590 ± 0.009,0.724 ± 0.005 and 0.34 ± 0.016,respectively,which was higher than that in the normal pressure group (0.081 ±0.013),with signifi cant difference (all P ＜ 0.01),and the difference approached statistical significance between each two time points in this group (all P ＜ 0.01).The expression level of P53 in anti-Caspase 9 and anti-Caspase 8 group was 0.535 ± 0.007 and 0.703 ± 0.010,respectively,which was significantly lower than that in the control group (0.727 ± 0.021),and the difference was statistically significant (all P ＜ 0.01).The expression of Bcl2 was 0.312 ± 0.003 and 0.442 ± 0.011,respectively,which were significantly lower than that in the control group (0.501 ± 0.011),with statistical difference (P ＜ 0.01).Finally,the expression of P53 and Bcl-2 in anti-Caspase 9 group was lower than that of anti-Caspase 8 group (P ＜ 0.01),indicating that anti-Caspase 9 had more enhanced inhibitory effect on the apoptosis of corneal endothelial cells than anti-Caspase 8.Conclusion AntiCaspase 9 inhibitor could effectively block the corneal endothelial cell apoptosis induced by high pressure.And the damage from high pressure on corneal endothelial cells mainly triggers the release of cytochrome C from chondriosome to activate the endogenous enzyme linked apoptotic pathway in which Caspase 9 involves.