Effect of low fat diet on lipid absorption and fatty-acid transport following bowel resection

Low-fat diets (LFD) are used extensively in many different clinical conditi ons. However, the effect of this diet on lipid absorption and cellular long -chain fatty-acid (LCFA) transport is unknown. Fatty-acid translocase (FAT) , the rat homologue of human CD36, is one of several LCFA plasma-membrane t ransport proteins that may play an important role in intestinal lipid uptak e. The purpose of this study was to investigate the effects of a LFD on int estinal expression of FAT/CD36, enterocyte fatty-acid transport, and in-viv o lipid absorption in rats following bowel resection. Adult male Sprague-Da wley rats were divided into five experimental groups: normal rats fed norma l chow(NR-NC) (10 kcal% fat), normal rats fed a LFD (NR-LFD) (3 kcal% fat), sham rats fed normal chow (Sham-NC), short-bowel syndrome rats fed normal chow (SBS-NC), and SBS rats fed a LFD (SBS-LFD). SBS rats underwent 75% sma ll-bowel resection, while sham animals underwent bowel transection and rean astomosis. Food intake, fecal mass, and fecal fat were measured over the la st 3 days before death on day 14. Final body weight, plasma lipids and prot ein, and tissue total lipids in liver, adipose tissue, and intestine were d etermined at death. Total RNA from the mucosa of the duodenum, jejunum, and ileum was extracted for Northern blot analysis to determine fatty-acid tra nslocase (FAT)/CD36 mRNA levels. An established cellular LCFA transport ass ay was used to determine isolated enterocyte [H-3]-oleate uptake. Students' s t-test was used to determine statistical significance (P < 0.05). NR-LFD rats demonstrated a small increase in overall food absorption and no change in fat absorption compared to NR-NC animals. A significant decrease in FAT /CD36 mRNA levels was seen in the duodenum and jejunum in NF-LFD rats (vs N R-NC) and was accompanied by reduced LCFA transport by isolated enterocytes from the jejunum and ileum. SBS-LFD rats demonstrated decreased FAT/CD36 m RNA levels in all three segments and a concomitant decrease in LCFA uptake enterocytes compared to the SBS-NC group. In addition, SBS-LFD rats showed significantly lower final body weight and plasma lipids compared to SBS-NC animals.