[Role of Omi/HtrA2 in renal tubular cells apoptosis induced by post asphyxial serum of neonate].

OBJECTIVE

To investigate the mechanism of inducing apoptosis of Omi/HtrA2 in renal tubular cells with post asphyxial serum of neonate.

METHODS

Human renal proximal tubular cell line HK-2 cell was used as target cell. They were divided into three groups: control group, asphyxia group and Ucf-101 (Omi/HtrA2 special inhibitor) treated group. The challenge concentration of serum obtained from neonates 24 hours after asphyxia was 20%, and the treatment concentration of Ucf-101 was 10 mumol/L. The Omi/HtrA2 translocation in renal tubular cells was observed with confocal microscopy, and the rate of apoptosis was detected with flow cytometer.

RESULTS

It was found that Omi/HtrA2 was translocated into cytoplasm in asphyxia group, and the rate of Omi/HtrA2 translocation in HK-2 cells of asphyxia group was significantly increased [(28.1+/-3.6)% vs. (9.4+/-2.1)%, P<0.01]. Compared with the control group, after being treated with post asphyxial serum, the rate of apoptosis of HK-2 cells in asphyxia group was significantly increased [(36.3+/-4.4)% vs.(12.4+/-2.9)%, P<0.01]. Compared with asphyxia group, the rate of apoptosis in HK-2 cells in Ucf-101 treated group was significantly decreased [(27.0+/-3.9)% vs.(36.3+/-4.4)%, P<0.01].

CONCLUSION

These experimental data demonstrates that post asphyxial serum of neonate can induce apoptosis of HK-2 cells, and translocation of Omi/HtrA2 from mitochondria into cytoplasm may play an important role in its intracellular signal transduction mechanism in induction of apoptosis.