Long-term effects of small intestinal bypass on hepatic lipid content in congenitally obese rats

This study compares the early (30-d) with the late (14-month) effects of small intestinal bypass on hepatic lipid accumulation in congenitally obese Zucker rats. Heterozygote, lean and homozygote, obese Zucker rats underwent sham operations and homozygote obese rats underwent bypass of 90 percent of their small intestine. Evaluation of hepatic lipid content at 30 d following the operation demonstrated increased hepatic triglyceride content in homozygote obese rats compared to heterozygote lean rats; however, the homozygote rats with small intestinal bypass did not have significantly different hepatic triglyceride content from that present in the homozygote obese sham operated rats. Fourteen months following the operations hepatic lipid content increased from 63 +/- 14 mg/g liver in homozygote, obese sham operated rats to 132 +/- 55 mg/g in homozygote, obese rats with small intestinal bypass. The increased lipid was secondary to increased hepatic triglyceride content. Histologic evaluations of liver specimens demonstrated no increased inflammation, granuloma formation or fibrosis when sham operated rat liver tissue was compared to liver tissue from rats with intestinal bypass. These data indicate that at a late stage following small intestinal bypass, the obese Zucker rat develops hepatic steatosis, as do humans, and can serve as an experimental model for evaluation of methods to decrease the triglyceride accumulation.