Effect of carnosine on cerebral edema and oxidative stressbiomarkers in a transient model of focal cerebral ischemia in rats

Carnosine is an endogenous dipeptide expressed in many tissues including brain and has a protective effect against ischemic brain damage. However, its effect on brain edema, which is one of the most important variables in determining the amount of secondary brain damage after stroke, is not clear. The present study was conducted to investigate the effect of L-Carnosine on brain edema and oxidative stressbiomarkers in an experimental model of focal cerebral ischemia. Under Laser Doppler flowmetry, cerebral ischemia was induced by transient occlusion of middle cerebral artery for 1 hour in rats. L-Carnosine at doses of 250 and 500 mg/kg.ip was injected immediately after induction of ischemia. Cerebral edema and enzymes activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA) content were measured 24 hours after ischemia using a standard method and kit. Administration of L-Carnosine at doses 250(%81.5±0.36) and 500 (%80.9±0.30) mg/kg significantly reduced brain edema by 25% and 40% in comparison with the control group (%82.53±0.16), respectively (P<0.001). Additionally, treatment with L-Carnosine significantly reduced MDA content and increased activity of SOD, GPx and total antioxidant capacity in the brain ischemic tissue (P< 0.001). Results showed Carnosine has a protective effect against brain edema in an experimental model of stroke. This is probably due to increase of endogenous antioxidant enzymes, inhibiting free radical generation and attenuating of oxidative stress.