Carnosine pretreatment protects against hypoxia–ischemia brain damage in the neonatal rat model

Perinatal hypoxia–ischemia brain injury is a major cause of mortality and morbidity in neonates and lacks an effective treatment thus far. Carnosine has been demonstrated to play a neuroprotective role in the adult brain injuries. However, there is no information available concerning its neuroprotective role in the immature brains after hypoxia–ischemia insults. Therefore, we investigated whether carnosine could also confer neuroprotective effects in a neonatal rat hypoxia–ischemia model. Hypoxia–ischemia was induced in rats on postnatal day 7 (P7). Carnosine (250 mg/kg) was administered intraperitoneally, 30 min prior to hypoxia–ischemia induction. Morphological brain injury and biochemical markers of apoptosis and oxidative stress were evaluated 24 h after hypoxia–ischemia induction. Cognitive performance was evaluated by the Morris Water Maze test on P28–P33. We found that pretreatment with carnosine significantly reduced the infarct volume and the number of terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells in the hypoxia–ischemia brain. Carnosine also inhibited mRNA expression of apoptosis-inducing factor(AIF) and caspase-3, which was accompanied by an increase in superoxide dismutase(SOD)activity and a decrease in the malondialdehyde(MDA)level in carnosine-treated rats. Furthermore, carnosine also improved the spatial learning and memory abilities of rats declined due to hypoxia–ischemia. These results demonstrate that carnosine can protect rats against hypoxia–ischemia-induced brain damage by antioxidation.