Estrogen reduces CCL4- induced liver fibrosis in rats.
OBJECTIVE
Chronic liver diseases, such as fibrosis or cirrhosis, are more common in men than in women. This gender difference may be related to the effects of sex hormones on the liver. The aim of the present work was to investigate the effects of estrogen on CCL(4)-induced fibrosis of the liver in rats.


METHODS
Liver fibrosis was induced in male, female and ovariectomized rats by CCL(4) administration. All the groups were treated with estradiol(1 mg/kg) twice weekly. And tamoxifen was given to male fibrosis model. At the end of 8 weeks, all the rats were killed to study serum indicators and the livers.


RESULTS
Estradiol treatment reduced aspartate aminotransferase(AST), alanine aminotransferase (ALT), hyaluronic acid(HA) and type IV collagen(CIV) in sera, suppressed hepatic collagen content, decreased the areas of hepatic stellate cells (HSC) positive for alpha-smooth muscle actin (alpha-SMA), and lowered the synthesis of hepatic type I collagen significantly in both sexes and ovariectomy fibrotic rats induced by CCL(4) administration. Whereas, tamoxifen had the opposite effect. The fibrotic response of the female liver to CCL(4) treatment was significantly weaker than that of male liver.


CONCLUSIONS
Estradiol reduces CCL(4)-induced hepatic fibrosis in rats. The antifibrogenic role of estrogen in the liver may be one reason for the sex associated differences in the progression from hepatic fibrosis to cirrhosis.
Xu
Jun-Wang
JW
Department of Gastroenterology, Second Hospital of Xi'an Jiaotong University, Xi'an 710031, Shaanxi Province, China. xujw@pub.xaonline.com
Gong
Jun
J
Chang
Xin-Ming
XM
Luo
Jin-Yan
JY
Dong
Lei
L
Hao
Zhi-Ming
ZM
Jia
Ai
A
Xu
Gui-Ping
GP
D000199:Actins / Q000032:analysis; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001219:Aspartate Aminotransferases / Q000097:blood; D015415:Biomarkers; D002251:Carbon Tetrachloride; D024042:Collagen Type I / Q000032:analysis; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D008099:Liver / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D010982:Platelet-Derived Growth Factor / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013629:Tamoxifen / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000032:analysis; D053773:Transforming Growth Factor beta1
D000199:Actins; D000975:Antioxidants; D015415:Biomarkers; D024042:Collagen Type I; D004965:Estrogen Antagonists; D004967:Estrogens; D010982:Platelet-Derived Growth Factor; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D013629:Tamoxifen; D002251:Carbon Tetrachloride; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase