Critical role of Ghrelin in downregulation of the inflammatory response after renal injury

Abstract

BACKGROUND: The impairment of blood flow to the kidney causes renal injury occurs by ischemia/reperfusion (I/R) in surgical procedures, in which the kidneys remain without blood supply for sometime. This is observed during kidney transplantation, vascular surgery of aorta and renal arteries, and in partial nephrectomy. Ghrelin is an orexigenic growth hormone secretagogue of a 28 amino acid peptide derived mainly from ghrelinergic cells in the gastrointestinal tract. It plays an important physiological role in regulating of energy homeostasis and appetite stimulant. In this study, we aimed to assess the ability of ghrelin to exert potential protective effects on the kidney I/R and subsequent kidney dysfunctions in the rat through the modulation of pro-inflammatory cytokines. MATERIALS AND METHODS: A total of 28 rats were used in this experiment and the I/R was induced in a rat model by unilateral renal artery clamping for 30 min and reperfusion for 3 h, and ghrelin (40 μg/kg/rat) or vehicle was injected through intraperitoneal before ischemia and at reperfusion time immediately. Ghrelin administration could exert a protective role in the kidney against injury by significantly reducing serum and tissue levels of pro-inflammatory markers (tumor necrosis factor-alpha, high mobility group box protein 1, and interleukin 1 beta), decreasing the serum levels of (urea and creatinine), and reduction of the severity score of renal damage. CONCLUSIONS: We conclude that ghrelin has renoprotective effects through modulation of inflammation.

Keywords

• ghrelin
• high mobility group box protein 1
• ischemia
• reperfusion
• tumor necrosis factor-alpha