ANTIBIOTICS PREVENT LIVER-INJURY IN RATS FOLLOWING LONG-TERM EXPOSURE TO ETHANOL

Background/Aims: Kupffer's cells participate in alcohol-induced liver injury, and endotoxemia is observed in human alcoholics and in a rat model. This study evaluated the effect of reducing bacterial endotoxin production by intestinal sterilization on alcohol-induced liver injury. Methods: Male Wistar rats were exposed to ethanol continuously for up to 3 weeks via intragastric feeding. The gut was sterilized with polymyxin B and neomycin. Results: Fecal culture of stool samples from ethanol-fed rats treated with antibiotics showed virtually no growth of gram-negative bacteria. Endotoxin levels of 80-90 pg/mL in plasma of ethanol-fed rats were reduced to <25 pg/mL by antibiotics. Antibiotic treatment also completely prevented elevated aspartate aminotransferase levels and significantly reduced the average hepatic pathological score in rats exposed to ethanol. Oxygen tension on the surface of the liver measured in vivo was decreased significantly from control values of 48 +/- 1 to 39 +/- 1 mu mol/L in ethanol-treated rats. This hypoxia was prevented by treatment with antibiotics. Moreover, the increase in rates of ethanol elimination due to long-term ethanol treatment was prevented by antibiotic treatment. Conclusions: Intestinal sterilization prevented alcohol-induced liver injury in the rat, supporting the idea that hypermetabolism and consequent hypoxia caused by activation of Kupffer's cells by endotoxin is involved in the mechanism.