Effect of Ghrelin on gastrointestinal motility after traumatic brain injury / 中华创伤杂志

ABSTRACT

Objective To investigate the effect of Ghrelin on gastrointestinal motility after traumatic brain injury (TBI).Methods A total of 72 adult male SD rats were randomly divided into sham operation group (n =8),TBI group (n =32) and Ghrelin group (n =32),according to the random number table.In the sham operation group,the scalp was sutured after craniotomy and sterilization,without any strike.In the TBI group,after intraperitoneal anesthesia,the skull was opened and the electric cortical contusion impactor was used to strike the center of bone window at the depth of 3 mm and the rate of 5 m/s.The duration of hitting the lowest point was 200 ms.In the Ghrelin group,20 μg/kg of Ghrelin was injected into the rat via the tail vein 30 minutes after injury.The modified neurologicalseverity score (mNSS),percentage of water content in feces and percentage of gastric contents in body weight at 6,24,48 and 72 hours after operation in each group were measured.The stomach,the small intestine 15 cm from ileocecal junction,ileocecal junction (about 3 cm in the proximal ileal loops,about 3 cm in the distal ileal loops,and 3 cm colon loops) were taken out to prepare the electron microscopy section and observe the microscopic changes of the gastrointestinal mucosa.Results The mNSS in the TBI and Ghrelin groups was higher than that in the sham operation group after 24,48 and 72 hours (P ＜0.01).The mNSS in the TBI group was higher than that in the Ghrelin group after 24,48 and 72 hours (P ＜0.01).In the sham operation group,the intestinal wall was pink.In the TBI group,gastric dilatation and thinner wall with pale or dark red color were seen,and small intestine cavity expansion with dark color and even congestion were observed.There was much mucus in the intestinal wall.The Ghrelin group improved obviously than the TBI group after 6 hours.Compared with the Ghrelin group,the percentage of fecal water content in the TBI group decreased significantly after 24 hours (P ＜ 0.05),and the decrease rate dropped with time.Obvious delayed gastric emptying occurred (P ＜ 0.05),and the percentage of gastric contents in body weight demonstrated downtrend.The changes of gastric mucosa were as followsthe chief cells in the gastric glands were observed 72 hours after TBI in the TBI group,and scattered short microvilli were seen in the cell surface.The cytoplasm protruded into the glandular cavity,and a large number of rough endoplasmic reticulum could be seen in the cytoplasm,with irregular arrangement.Medullary bodies could be seen inside the mitochondria which swelled locally.Abundant endocrine granules were seen in the cytoplasm.Mitochondria were scattered and swollen,and mitochondria cristae became shorter and fewer,which contained medullary bodies.The Ghrelin group improved obviously than TBI group after 72 hours in terms of gastric mucosa changes.With respect to cecum mucosa,in the TBI group 72 hours after TBI,severe edema of the cecum absorption epithelium,obvious dilation of the rough endoplasmic reticulum,expansion of the free water gap inside the cell,and local decrease of the microvilli at the top of the cell were observed.Abundant microvilli were seen in the cecum absorption epithelium and cell top.The connection complex composed of tight connections,intermediate connections,and bridging particle connections could be seen between cells.The Ghrelin group improved obviously than TBI group after 72 hours in terms of cecum mucosa changes.Conclusions Ghrelin can improve gastrointestinal motility and protect gastrointestinal mucosa in rats after TBI.