Nitric oxide synthase mediates the antioxidant effect of L-Arginine in the brain of mice subjected to chronic restrain stress

Document Type : Research article


1 Department of Physiology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt 83525

2 General Authority for Veterinary Services, Ph.D in Pathology and Clinical Pathology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt


Chronic restraint stress (CRS) immobilize animal and induces the production of oxidative radicals as a preliminary cause of various health complications. CRS-induced oxidative stress led to pathological changes in brain tissue and consequently the general body condition. Thus, we elucidated the potential protective impact of L-Arginine (L-Arg), conditional amino acid and essential source of nitric oxide, on oxidative stress and brain tissue. BALB/c mice were randomly divided into five groups (n = 6) that received either 1) daily intraperitoneal (I.P) injection of phosphate-buffered saline (PBS) (Control group) (0.5ml), 2) I.P injection of PBS in combination with CRS (2h/day for 10 consecutive days) (CRS group), 3) I.P injection of L-Arg (500 mg/kg b.wt) with CRS (L-Arg + CRS group), 4) L-Arg alone (L-Arg group), or 5) pretreatment with I.P injection of L-NG –nitro-L-arginine methyl ester (l-NAME) (30 mg/kg b.wt), a potent common inhibitor of nitric oxide synthase (NOS), 30 minutes before L-Arg injection and CRS application (L-Arg + L-NAME + CRS group). Total antioxidant capacity (T-AOC), catalase, and histopathological status of brain tissue were evaluated. CRS significantly suppressed the T-AOC compared to the control. Furthermore, L-Arg elevated the T-AOC whereas L-NAME significantly reversed the action of L-Arg on CRS-induced T-AOC. L-Arg could not rescue CRS-decreased catalase. It is concluded that NOS is an essential mediator of the L-Arg ameliorative effect on CRS-induced oxidative stress in serum and brain tissue. Moreover, L-Arg antioxidant action is not mediated by catalase.


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