Postoperative intestinal dysmotility in rats: role of inducible Nitric oxide

ABSTRACT

Postoperative dysmotility of the gastrointestinal tract occurs after essentially every abdominal operation and remains one of the most perplexing problems in medicine. We proposed that inducible nitric oxide [NO] plays a role in postoperative intestinal dysmotility. Rats were underwent or not surgical intestinal manipulation. Spontaneous circular muscle contractions were recorded in both experimental groups in vitro, 24 hours after surgery. Nitrite production were measured in muscularis culture of both normal control and manipulated small bowel. Histological examination for intestinal leukocytic infiltration was also done. Intestinal manipulation resulted in a significantly diminished spontaneous contractile activity of manipulated small intestine. In control rats, selective iNOS inhibition [L-NIL] did not increase spontaneous muscle activity but after manipulation, L-NIL significantly improved the spontaneous muscle contractility. Nitrite production increased significantly from cultures of intestinal muscularis obtained from rats 24 hours after manipulation. Leukocytes invaded massively the intestinal muscularis of manipulated rats but not of normal control rats. These results show that leukocyte derived inducible NO inhibits small intestinal motility after manipulation and it probably plays an essential role in the pathophysiology of postoperative dysmotility