The effect of PARS inhibition on ileal histopathology, apoptosis and lipid peroxidation in LPS-induced obstructive jaundice

Abstract

In our experimental study, we investigated the protective effect of 3-aminobenzamide (3-AB), the poly (ADP-ribose) synthetase (PARS inhibitor), on the ileal histopathology and the apoptosis in lipopolysaccharide (LPS)-induced inflammation in rats with obstructive jaundice (OJ). We randomized 40 rats into five groups. Group 1: sham group; Group 2: OJ group; Group 3: OJ+LPS; Group 4: OJ+3-AB+LPS; Group 5: OJ+LPS+3-AB. At the fifth day; the rats were jaundiced. In Group 3; 10 mg kg −1 LPS was injected intraperitoneally at the fifth day and then after 6 h the rats were sacrificed. In Group 4; 10 mg kg −1 3-AB was administrated intraperitoneally at the fifth day and repeated daily for 3 days and at the eighth day, 10 mg kg −1 LPS was injected intraperitoneally. In Group 5, 10 mg kg −1 LPS was injected intraperitoneally at the fifth day and after 6 h 10 mg kg −1 3-AB was administrated intraperitoneally and repeated daily for 3 days. At the eighth day, rats were sacrificed. Blood samples were taken for detection of serum MDA levels. Ileum samples were taken after relaparotomy for histopathological examination to evaluate the endotoxin-related intestinal injury and Caspase-3 apoptosis and for detection of tissue MDA and ATPase activities. There was marked destruction of villous and crypt epithelial cells and extensive apoptosis in Groups 3 and 5 in histopathological examination. In Group 4, the scores of intestinal mucosal damage and apoptotic cells were reduced significantly ( P<0.05). On the other hand, the scores of intestinal mucosal damage and apoptotic cells were not improved in Group 5. After the administration of 3-AB (Group 4), serum and ileal MDA levels decreased, ileal ATPase increased as compared to Groups 1 and 2. Our study showed that 3-AB prevented the mucosal damage and apoptotic loss of intestinal epithelial cells significantly if it was administrated before LPS. However, 3-AB failed to prevent the mucosal damage and apoptotic loss of intestinal epithelial cells significantly if there was established endotoxemia in OJ.