Orexin-A Improves Hepatic Injury Following Renal Ischemia Reperfusion in Rats

Introduction: Orexins are novel neuropeptides that are localized in neurons in the lateral hypothalamus. They are implicated in a wide variety of physiological functions. Orexin peptides and receptors are found in many peripheral organs such as kidneys. It has been demonstrated that exogenous orexin-A can induce protective effects against ischemia–reperfusion injury in many organs. The goal of this study was to determine the effect of orexin-A on the hepatic dysfunction and histological damage induced by renal ischemia/ reperfusion at an early stage. Methods: Pentobarbital anaesthetized rats were prepared for measuring renal functional variables. Ischemia was induced by bilateral renal artery clamping for 30 min followed by a 1 h reperfusion period. In orexin-treated rats, it was infused at 500 pmol·kg−1·min−1 (i.v.) from the beginning of pre-ischemic (pretreatment) clearance period. The liver was examined using light microscopy. Results: The renal ischemic challenge resulted in hepatic functional and histological damages, which were associated with decreased creatinine clearance during the reperfusion period. In orexin-treated rats, the functional and histological damages to the liver were improved along with the decrease in creatinine clearance being smaller than those of the non-treated rats. Conclusion: Orexin-A exhibited an ameliorative effect against renal ischemia/reperfusion-induced lesions in the liver.