Published online Apr 15, 2002. doi: 10.3748/wjg.v8.i2.363
Revised: August 15, 2001
Accepted: August 23, 2001
Published online: April 15, 2002
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 × 10-6 IU•cell-1 to 780 ± 62 × 10-6 IU•cell-1) and MDA (from 0.28 ± 0.07 × 10-6 nmol·cell-1 to 1.35 ± 0.12 × 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 × 10-6 IU•cell-1 (P < 0.01 vs oxidative group), 530 ± 37 × 10-6 IU•cell-1 (P < 0.01 vs oxidative group), 687 ± 42 × 10-6 IU•cell-1 (P < 0.05 vs oxidative group) respectively, and the MDA level are 0.71 ± 0.12 × 10-6 nmol•cell-1 (P < 0.01vs oxidative group), 0.97 ± 0.11 × 10-6 nmol•cell-1 (P < 0.01 vs oxidative group) and 1.27 ± 0.19 × 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.