Abstract: Objective: To investigate the effect of L-arginine (L-Arg) on the expression of heat shock protein 70 mRNA and protein in kidney cells and its renal protective effect and mechanism. Methods: Twelve weaned piglets were randomly divided into two groups (6 piglets per group): one was control group and the other was L-Arg group, both of which were consistent with each other in terms of sex, body weight and consanguinity. A daily basal diet was fed to both groups and in addition, L-Arg was supplemented to the basal diet for the L-Arg group. After 7 d of feeding, all the piglets were killed, and plasma was collected for determination of the contents of L-Arg, ornithine (Orn) and citrulline (Cit) and kidney was also collected to determine the mRNA expression levels of HSP70 and inducible nitric oxide synthase (iNOS) by PCR and the protein expression levels of HSP70 and iNOS by Western blotting and to observe morphological changes. Results: L-Arg supplementation significantly increased plasma levels of L-Arg and Orn, mRNA expression levels of HSP70 and iNOS and HSP70 protein expression level and reduced the number of erythrocytes in kidney tubules. Conclusion: L-Arg supplementation to the diet of piglets can elevate HSP70 protein and mRNA expression and iNOS mRNA expression in the kidney and protect the kidney through maintaining the conformational stability of proteins, inhibiting the activation of apoptotic pathways of cells and alleviating kidney damage induced by weaning stress.

Key words: L-Arg, kidney, HSP70, piglet