N -carbamylglutamate and l-arginine promote intestinal function in suckling lambs with intrauterine growth restriction by regulating antioxidant capacity via a nitric oxide-dependent pathway

Data indicate that intrauterine growth restriction (IUGR) in newborns can be partly alleviated through the supply of l-arginine (Arg) and N-carbamylglutamate (NCG). The current work aimed to explore whether Arg and NCG promote intestinal function by regulating antioxidant capacity in suckling lambs with IUGR via a nitric oxide (NO)-dependent pathway. Forty eight newly born Hu lambs with normal weights at birth (CON) or suffering from IUGR were randomly divided into 4 groups (n = 12 per group), namely, the CON, IUGR, IUGR + 1% Arg, and IUGR + 0.1% NCG groups. The animals were used for experiments from the age of day 7 to 28. Compared with the lambs in the IUGR group, the lambs in the Arg or NCG group had higher (P < 0.05) final body weights. The plasma insulin, NO, and NO synthase (NOS) concentrations in the IUGR group were higher (P < 0.05) compared with those in IUGR + 1% Arg or IUGR + 0.1% NCG. The jejunal level of the tumor necrosis factor α (TNF-α) in the IUGR lambs was greater (P < 0.05) compared with that in IUGR + 1% Arg or IUGR + 0.1% NCG. The plasma and jejunal total antioxidant capacity (T-AOC) values for the IUGR + 1% Arg or IUGR + 0.1% NCG group were greater (P < 0.05) compared with those for the IUGR group. Compared with the IUGR + 1% Arg or IUGR + 0.1% NCG lambs, the IUGR lambs had lower (P < 0.05) abundance of mRNA and protein abundance of glutathione peroxidase 1 (GPx1), catalase (CAT), superoxide dismutase 2 (SOD2), nuclear factor erythroid 2-related factor 2 (Nrf2), quinone oxidoreductase 1 (NQO1), heme oxygenase (HO-1), zonula occludens-1 (ZO-1), occludin, inducible NOS (iNOS), and epithelial NOS (eNOS). Overall, the data suggest that the Arg or NCG supplementation to suckling lambs with IUGR enhances the intestinal function by regulating the oxidant status via the NO-dependent pathway.