BENEFICIAL-EFFECTS OF L-ARGININE ON INTESTINAL EPITHELIAL RESTITUTIONAFTER ISCHEMIC DAMAGE IN RATS

The polyamines are involved in repair processes after intestinal ische mia. Arginine and ornithine, both precursors of polyamines were theref ore expected to exert beneficial effects on mucosal barrier dysfunctio n. Arginine may also generate NO and there is support for the view tha t NO may be beneficial after an ischemic insult. Male Wistar rats were given, by gavage, isonitrogenous solutions of L-arginine (0.5 g/kg) o r L-ornithine (0.7 g/kg) 17 and 2 h before ischemia. Controls received an isonitrogenous solution of casein hydrolysate (1 g/kg). Transient intestinal ischemia was produced in anesthetized rats by occluding the superior mesenteric artery for 90 min. Intestinal morphology, hydrola se activities, polyamine and cGMP contents, and cell proliferation rat es were determined 4 h after reperfusion, Administration of arginine o r ornithine did not prevent ischemic damage but accelerated morphologi cal repair, enhanced cell proliferation, and polyamine content was obs erved. Arginine was significantly more effective than ornithine. Forma tion of cGMP was enhanced after arginine administration. N-G-nitroargi nine methylester, an inhibitor of NO synthase, prevented the arginine effects on mucosal repair. We conclude that arginine-derived NO is an important mediator in the restitution of intestinal mucosa by minimizi ng cell injury during reperfusion.