Aim: To examine the protective effect of estradiol on the cultured hepatocytes under oxidative stress.
Methods: Hepatocytes of rat were isolated by using perfusion method, and oxidative stress was induced by a serum-free medium and FeNTA. MDA level was determined with TBA method. Cell damage was assessed by LDH assay. Apoptosis of hepatocytes was assessed with cytoflowmetric analysis. Expression of Bcl-xl in cultured hepatocytes was detected by Western blot. The radical-scavenging activity of estradiol was valued by its ability to scavenge the stable free radical of DDPH.
Results: Oxidative stress increased LDH from 168 +/- 25 x 10(-6)IU.cell(-1) to 780 +/- 62 x 10(-6)IU.cell(-1) and MDA(from 0.28 +/- 0.07 x 10(-6)nmol.cell(-1) to 1.35 +/- 0.12 x 10(-6)nmol.cell(-1)) levels in cultured hepatocyte, and estradiol inhibited both LDH and MDA production in a dose dependent manner. In the presence of estradiol 10(-6)mol.L(-1), 10( -7 )mol.L(-1) and 10(-8)mol.L(-1),the LDH levels are 410 +/- 53 x 10(-6)IU.cell(-1) (P<0.01 vs oxidative group), 530 +/- 37 X 10(-6)IU.cell(-1 ) (P<0.01 vs oxidative group), 687+/-42 x 10(-6)IU.cell(-1) (P<0.05 vs oxidative group) respectively, and the MDA level are 0.71+/-0.12 x 10(-6)nmol.cell(-1) (P<0.01 vs oxidative group),0.97+/-0.11 x 10(-6)nmol.cell(-1 )(P<0.01 vs oxidative group) and 1.27+/-0.19 x 10(-6)nmol.cell(-1) respectively. Estradiol suppressed apoptosis of hepatocytes induced by oxidative stress, administration of estradiol(10(-6)mol/L)decreased the apoptotic rate of hepatocytes under oxidative stress from 18.6 +/- 1.2% to 6.5 +/-2.5%, P<0.01. Bcl-xl expression was related to the degree of liver cell damage due to oxidative stress, and estradiol showed a protective action.
Conclusion: Estradiol protects hepatocytes from oxidative damage by means of its antioxidant activity.