Effect of adrenomedullin on rat renal tubular epithelial cell apoptosis induced by hypoxia-reoxygenation and its mechanism / 中华肾脏病杂志

ABSTRACT

Objective To investigate the effect of adrenomedullin on rat renal tubular epithelial cell line (NRK-52E) apoptosis induced by hypoxia-reoxygenation (HR) injury and its mechanism.Methods NRK-52E cells were cultured and randomly allotted to the following 4 groups:control group,HR group,empty plasmid + HR group,ADM + HR group.NRK-52E cells were transfected with pcDNA3.1-myc-his B empty vector or pcDNA3.1-ADM by transfection complex comprising optimal proportion of plasmid and Fugene HD reagents.Cells were counted by trypanblau and cell survival rate was computed.The concentration of lactate dehydrogenase (LDH) was detected by spectrophotometric method to evaluate cell vitality.The apoptotic rate of NRK-52E cells was measured by flow cytometry.The transfer efficiency was detected by immunocytochemistry.The mRNA expressions of ADM,Bax,Bcl-2 and Fas were determined by Semi-quantitative RT-PCR,and active caspase-3,8,9 protein expression were examined by Western blotting.Results Compared with control group,the expression of ADM significantly increased in HR group (P ＜ 0.05).The expression of ADM significantly increased in ADM + HR group than that in empty plasmid + HR group.Compared with control group,in HR group,the living cell counts and cell survival rate significantly decreased; the LDH concentration in media,apoptotic rate and the levels of Bax,Bcl-2,Bax/Bcl-2,Fas,active Caspase -3,8,9 significantly increased (all P ＜ 0.05).Compared with HR group,in ADM + HR group,the living cell counts and cell survival rate significantly increased; the LDH concentration in media,the cell apoptotic rate and the levels of Bax,Bax/Bcl-2,Fas,active Caspase-3,8,9 significantly decreased,while Bcl-2 was promoted (all P ＜ 0.05).The above indexes had no differences between empty plasmid + HR group and HR group (all P ＞ 0.05).Conclusion The increased expression of ADM can inhibit NRK-52E apoptosis induced by HR,and the mechanism might be achieved by inhibiting mitochondrial and death receptor-mediated apoptotic pathways.