Effect of bilirubin in ischemia/reperfusion injury on rat small intestine☆

Purpose: The aim of this study was to determine the effects of bilirubin in experimental small intestinal ischemia/reperfusion (I/R) injury in rats. Methods: Thirty rats were divided into 5 groups (n = 6). In group S, saline and in group B, bilirubin, 20 mg/kg were infused via the jugular vein without an additional procedure. In groups S-IR, saline, B₁-IR and B₂-IR, 10 and 20 mg/kg/h of bilirubin were infused for 2 hours, respectively. In these groups, an I/R procedure was done after infusions by occluding the superior mesenteric artery for 45 minutes followed by 1 hour of reperfusion. After reperfusion, the small intestines were resected for histopathologic and malondialdehyde (MDA) assessments. Mucosal lesions were scored between 0 and 5. Malondialdehyde levels and histopathologic grades were analyzed statistically. Results: Mucosal injury was severe in S-IR (grade 4 to 5), mild in B₁-IR (grade 0 to 3) and none in B₂-IR group (grade 0). Grades of group S-IR were higher than those of B₁-IR and B₂-IR statistically (P <.05). Tissue MDA levels of the S-IR group were significantly higher than those of B₁-IR and B₂-IR groups (U = 36, P < .05). Bilirubin levels correlated inversely with MDA levels (r = −0.94). Conclusions: Bilirubin effectively prevents intestinal I/R injury in rat. This observation is consistent with the hypotheses regarding bilirubin as an antioxidant, having a role in the body defense. J Pediatr Surg 36:1764-1767. Copyright © 2001 by W.B. Saunders Company.