Effect of ethyl-3,4 dihydroxybenzoate pretreatment on the tubular epithelial cells apoptosis induced by albumin and hypoxia / 中华肾脏病杂志

ABSTRACT

Objective To explore the effects of ethyl-3,4 dihydroxybenzoate(EDHB), a prolyl hydroxylase inhibitor, pretreatment on the tubular epithelial cells apoptosis induced by albumin and hypoxia. Methods To investigate the effects of albumin and hypoxia on cells, rat tubular epithelial cells(NRK-52E)were incubated for 24 h in(1)normoxia(5%CO2);(2)hypoxia(1% O2);(3)albumin(30 g/L)under normoxia;(4)albumin(30 g/L)under hypoxia. To investigate the effects of EDHB pretreatment on cells apoptosis, NRK-52E were incubated in hypoxia for 24 h in(1)normoxia;(2)hypoxia;(3)hypoxia+albumin(30 g/L);(4)hypoxia+EDHB(500 μmol/L);(5)EDHB pretreatment(albumin 30 min after EDHB). Apoptosis was measured by flow cytometry(AnnexinV-FITC-PI). bcl-2, bax and vascular epithelial growth factor(VEGF)mRNA expression were detected by RT-PCR. VEGF protein expression was detected by Western blotting. Results NRK-52E apoptosis was not significantly different between hypoxia and norraoxia groups(P>0.05), but increased significantly in albumin(30 g/L)under hypoxia group compared with albumin(30 g/L)under normoxia group(37.36%?.95% vs 25.59%?.32%, P< 0.05). There was an increase in bax mRNA expression and a decrease in bcl-2 mRNA expression in albumin(30 g/L)under hypoxia group compared with albumin(30 g/L)under normoxia group(P< 0.05). EDHB pretreatment improved these impairments of albumin(30 g/L)under hypoxia on NRK-52E(P< 0.05). VEGF expression elevated in hypoxia compared with normoxia(P<0.05), decreased in albumin(30 g/L)under hypoxia groups compared with that without albumin groups(P<0.05).EDHB pretreatment significantly improved VEGF expression compared with albumin(30 g/L)under hypoxia group(P <0.05). Conclusion NRK-52E cells apoptosis induced by albumin is accelerated by hypoxia, however partially improved by EDHB pretreatment, probably through the up-regulation of VEGF expression.