Use of reverse transcription–polymerase chain reaction to evaluate in vivo cytokine gene expression in rats fed ethanol for long periods

We evaluated the expression of interleukin‐1α, interleukin‐1β, tumor necrosis factor‐α and transforming growth factor‐β mRNAs in the intragastric‐feeding rat model of alcoholic liver disease. Rats were fed different diets for periods of 2 or 4 wk. Animals fed saturated fat and ethanol and the corn oil–dextrose control group had no liver injury, whereas animals fed corn oil and ethanol showed pathologic changes. RNA was extracted from the livers at the time of killing, reverse‐transcribed and amplified; polymerase chain reaction products were subjected to electrophoresis on agarose gel. Interleukin‐1α mRNA was present in all groups at 2 and 4 wk; interleukin‐1β and transforming growth factor‐β mRNAs were present in all groups at 4 wk. Tumor necrosis factor‐α mRNA was absent in all groups at 2 wk but was present in the corn oil–ethanol group only at 4 wk. Because pathological liver injury was evident in the corn oil–ethanol group by 4 wk, the presence of tumor necrosis factor‐α mRNA at this time suggests a pathogenetic role for tumor necrosis factor‐α in alcohol‐induced liver injury. (HEPATOLOGY 1994;19:1483–1487.)