Effect of ghrelin on brain edema induced by acute and chronic systemic hypoxia

► Systemic normobaric hypoxia increased brain water content in both acute and chronic hypoxia. ► Administration of ghrelin reduced brain water content only in acute hypoxia. ► Serum TNF-α levels increased in acute hypoxia and ghrelin could reduce it. ► Both acute and chronic systemic hypoxia decreased body weights. ► Administration of ghrelin prevented further weight loss in chronic hypoxia group. Hypoxia is an important pathogenic factor for the induction of vascular leakage and brain edema formation. Recent studies suggest a role for TNF-α in the induction of brain edema. Ghrelin attenuates the synthesis of TNF-α following subarachnoid hemorrhage and traumatic brain injury (TBI). Therefore, we examined the effects of ghrelin on the brain edema, serum TNF-α levels and body weight in a systemic hypoxia model. Adult male Wistar rats were divided into acute and chronic controls, acute or chronic hypoxia and ghrelin-treated (80μg/kg/ip/daily) acute or chronic hypoxia groups. Systemic hypoxia was induced in rats by a normobaric hypoxic chamber (O2 11%) for two days (acute) or ten days (chronic). Effect of ghrelin on brain edema and serum TNF-α levels was assessed by dry–wet and ELISA method, respectively. The results showed that acute (P