Retinyl-palmitate reduces liver fibrosis induced by biliary obstruction in rats.

BACKGROUND/AIMS: The administration of retinoid in various experimental models of induced hepatic cirrhosis has shown antifibrogenic effects. The purpose of this study was to verify if vitamin A could interfere in hepatic fibrosis induced by biliary obstruction. METHODOLOGY: Male Wistar rats that underwent biliary obstruction were treated 2 weeks before the surgery with a dose of 50 x 10(3) IU retinyl-palmitate, twice a week, and then given the dosage for 5 weeks following surgery. They were then sacrificed and hepatic fragments removed to find out the biochemical dosage of hydroxyproline and the stereologic volume of collagen. Blood samples were also collected to find the biochemical dosage. RESULTS: The rats that underwent biliary obstruction and received vitamin A presented lower levels of hepatic hydroxyproline (p < 0.001) as well as a lower percentage of collagen tissue than the untreated control rats, but they presented higher AST and ALT serum levels (p < 0.05, p < 0.05). CONCLUSIONS: Under the above experimental conditions, the administration of vitamin A significantly reduced hepatic fibrosis.

A new method for the experimental induction of secundary biliary cirrhosis in wistar rats

The aim of this study was to describe a method for the induction of experimental secondary biliary fibrosis (SBF). Forty-seven Wistar rats were submitted to hepatic duct obstruction (OB group) for thirty days without ligature, section or cannulization causing interruption of biliary flow. This technique was carried out by simple traction of the bile duct passing it through the xiphoid appendix. Nine rats were submitted to a sham operation for bile duct stricture and seven rats comprised the control group. Blood samples were collected for the measurement of total bilirubin (TB), alkaline phosphatase (AP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Liver fragments were removed for morphological study. Thirty days after surgery TB, AP, ALT and AST levels were significantly increased in the hepatic duct ligation group compared to the sham operated group and the presence of SBF in the OB group was confirmed by morphological study of the liver. There was technical failure in 31.92 percent cases. The survival was 100 percent at fifteen days and 82.97 percent at the end of the experiment. We concluded that this simple surgical technique may be used to study the consequence of bile duct obstruction which could be a reversible process depending on the obstruction time. This technique can be carried out from cholestasis to fibrosis.