Effect of melatonin on gunfire noise stressª²induced gastric mucosal lesions in rats and its mechanism

    CUI Hongª²Yong, LIU Fangª²E, ZHANG Lei, HUANG Xiaoª²Jun, LIU Tao, LI Sha, HUANG Bo, HAN Ning

    Team 14, Cadet Brigade , School of Stomatology, Center of Basic Medicine Teaching Experiment, School of Basic Medicine, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To explore the effect of melatonin (MT) on gunfire noise stressª²induced gastric mucosal lesions in rats and its mechanism. METHODS: Fourteen SD rats were divided into 2 groups: experimental group (gunfire noise stress + MT ),control group (gunfire noise stress + sodium chloride ). The 120 dB gunfire noise was applied to establish psychological stress model in rats. Experimental group and control group were given intraperitoneal injection of MT (15 mg/kg) and equal volume sodium chloride , respectively, 30 min before stress. Eight hours after stress, plasma levels of calcitonin geneª²related peptide(CGRP), motilin(MTL), malondialdehyde(MDA) and superoxide dismutase(SOD) were measured by the radioimmunoassay and histochemical method. The gastric mucosal changes in each group were observed, and the mucosal lesion index, histological changes were evaluated. RESULTS: The mucosal damage 8 h after stress was slighter in the experimental group than that in the control group. The mucosal lesion index decreased significantly (P<0.01), the plasma levels of CGRP and SOD both increased significantly (P<0.05 and P<0.01 respectively), the plasma levels of MTL and MDA both decreased significantly (P<0.05) in the experimental group as compared with those in the control group. CONCLUSION: MT is effective in preventing noise stressª²induced gastric mucosal lesion. The mechanism may be related with the increase of gastric mucosal blood flow, the elimination of gastric mucosal free radical and the depression of gastric motor and the secretion of gastric acid by MT. ......