Metabolism/NutritionCombination treatment of parenteral arginine and nitric oxide inhibitor NG-nitro-L-arginine methyl ester in rats with peritonitis

PurposeIt has been shown that parenteral arginine may facilitate ureagenesis and improve leukocytic and splenocytic immunity and that the infusion of nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) may facilitate the production of arginine-associated amino acids in rats with subacute peritonitis. Herein, we investigated the effects of the combined treatment of parenteral arginine and L-NAME on arginine metabolism and inflammatory response.Methods and materialsMale Wistar rats underwent cecal puncture for induction of subacute peritonitis and were infused with conventional parenteral nutrition (arginine 0.95 g/kg/d) or parenteral nutrition supplemented with arginine (1.88 g/kg/d), L-NAME (25 mg/kg/d), or arginine plus L-NAME. Sham-operated and nonperitonitic rats with oral feeding (R group) or conventional parenteral nutrition (TPN group) were also included.ResultsAfter 7 d of parenteral feeding, the L-NAME treatment significantly attenuated the peritonitis-induced reduction in body weight gain (1-way ANOVA, P < 0.05) and had a significant impact on decreasing body water percentage and on increasing body fat percentage and serum insulin concentrations (2-way ANOVA, P < 0.05). Parenteral arginine had a significant impact on increasing plasma arginine and ornithine and on decreasing serum glutamate oxaloacetate transaminase and plasma nitrite/nitrate in peritonitic rats. In addition, plasma interleukin-6 was significantly decreased by arginine and/or L-NAME treatment, and plasma prostaglandin E2 was significantly decreased by arginine plus L-NAME treatment.ConclusionThese results suggest that the combination treatment of parenteral arginine and L-NAME may improve liver function and alleviate inflammatory response in rats with subacute peritonitis; however, it seems that parenteral arginine treatment is more beneficial than L-NAME.