Role of ghrelin in small intestinal motility following pediatric intracerebral hemorrhage in mice.

Small intestinal motility (SIM) disorder is a common complication following pediatric intracerebral hemorrhage (ICH), leading to a poor prognosis in patients. Previous studies have shown that ghrelin is involved in SIM in various diseases; however, the role of ghrelin in pediatric ICH‑induced SIM disorder remains to be elucidated. The present study was designed to investigate the association between ghrelin and SIM post‑ICH, and to examine the effect of exogenous ghrelin administration on SIM in vivo. An ICH model was induced in mice by autologous blood infusion. Neurobehavioral deficits were evaluated using a Rotarod test, forelimb placing test, and corner turn test. Intestinal mucosal damage was examined using hematoxylin and eosin staining. SIM was measured using charcoal meal staining. An enzyme‑linked immunosorbent assay was used to evaluate serum levels of ghrelin and nitric oxide (NO). Reverse transcription‑quantitative polymerase chain reaction and western blot analyses were performed to determine the levels of inducible nitric oxide synthase (iNOS), neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) at the mRNA and protein levels. Nω‑nitro‑L‑arginine methyl ester hydrochloride (L‑NAME), L‑arginine, atropine, phentolamine and propranolol were used to manipulate the putative pathways induced by ghrelin. Neurological dysfunction was observed post‑ICH. ICH caused damage to the intestinal mucosa and delayed SIM. Serum levels of ghrelin increased between 3 h and 3 days, peaking at 12 h, and showed a significant negative correlation with SIM post‑ICH. Ghrelin administration dose‑dependently attenua-ted ICH‑induced SIM disorder. Ghrelin also decreased NO levels by downregulating the mRNA and protein expression levels of iNOS, but not those of nNOS or eNOS, post‑ICH. Consistently, the effect was enhanced by L‑NAME and weakened by L‑arginine, respectively. The protective effect of ghrelin was eradicated by atropine, but not phentolamine or propranolol. These findings suggested that ghrelin ameliorated SIM disorder by downregulating iNOS/NO via the cholinergic pathway. Therefore, ghrelin may serve as a potential biomarker and useful target in ICH‑induced SIM disorder.