SNAP94847经腹侧被盖区至迷走神经背侧运动核对焦虑大鼠胃黏膜损伤作用研究

Effects of SNAP94847 on gastric mucosal injury via ventral tegmental area to dorsal motor nucleus of vagus nerve in anxiety rats

目的:探究黑色素浓集激素(MCH)受体1(MCHR1)拮抗剂SNAP94847能否作用于腹侧被盖区至迷走神经背侧运动核(VTA-DMV)神经通路,进而参与调控大鼠应激性焦虑所致胃黏膜损伤及其潜在机制。方法:采用荧光金逆行追踪结合免疫荧光组织化学法检测VTA-DMV的MCHR神经通路(n=10);采用单细胞外放电记录法检测大鼠VTA微量注射MCH或SNAP94847对多巴胺(DA)神经元放电活动的影响(n=30);18只大鼠随机分为正常+生理盐水(NS)组、焦虑+NS组和焦虑+SNAP94847组,观察VTA微量注射SNAP94847后大鼠行为学变化、胃黏膜炎症损伤及相关炎症指标的变化(n=6);24只焦虑模型大鼠随机分为假损毁+NS组、假损毁+SNAP94847组、电损毁+NS组及电损毁+SNAP94847组,观察电损毁DMV后VTA微量注射SNAP94847对胃黏膜炎症损伤相关炎症指标的影响(n=6)。结果:逆行追踪结合荧光免疫组织化学染色结果显示,VTA可见部分MCHR和荧光金双重标记神经元;MCH可改变大鼠VTA内DA神经元放电活动,且对焦虑模型大鼠的影响更显著(P<0.05);高架十字迷宫实验中,与对照组相比,焦虑+SNAP94847组进入闭合臂次数和时间百分比显著增加(P<0.05);焦虑模型大鼠炎症标志物过氧化氢酶(CAT)活性和谷胱甘肽过氧化物酶(GSH-Px)含量显著降低(P<0.05),髓过氧化物酶(MPO)活性及丙二醛(MDA)、肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)含量显著升高(P<0.05),VTA微量注射SNAP94847可显著减轻焦虑模型大鼠胃黏膜炎症损伤(P<0.05);与假损毁+SNAP94847组相比,电损毁+SNAP94847组焦虑模型大鼠CAT活性和GSH-Px含量显著降低(P<0.05),而MPO活性及MDA、TNF-α和IL-6含量显著升高(P<0.05)。结论:VTA-DMV的MCHR信号通路可能参与应激所致焦虑大鼠胃黏膜炎症损伤及焦虑样行为的调控。

AIM:To investigate whether SNAP94847,a melanin-concentrating hormone(MCH)receptor 1(MCHR1)antagonist,is involved in regulation of the neural pathway from ventral tegmental area to dorsal motor nucleus of vagus nerve(VTA-DMV)on stress-induced anxiety and gastric mucosal injury,and to explore its underlying mechanism.METHODS:The VTA-DMV neural pathway was detected by fluorescence immunohistochemical staining(n=10).The effects of microinjection of MCH or other drugs on the discharge activity of dopamine(DA)neurons were detected by single-cell discharge recording method(n=30).The rats(n=18)were randomly divided into normal+NS group,anxiety+NS group and anxiety+SNAP94847 group.The behavioral changes,gastric mucositis injury and related inflammatory indexes of the rats after VTA microinjection of SNAP94847 were observed(n=6).The anxiety rats(n=24)were randomly divided into sham lesion+NS group,sham lesion+SNAP94847 group,electrical lesion+NS group and electrical lesion+SNAP94847 group(n=6)to monitor the inflammatory indexes of the rats after DMV electrical lesion and VTA microinjection of SNAP94847.RESULTS:The results of retrograde tracing and fluorescence immunohistochemistry showed that there were MCHR and fluorescent gold double labeled neurons in VTA.MCH changed the discharge activity of DA neurons in VTA,and the effects on anxiety rats were more significant(P<0.05).In elevated plus maze experiment,the times and time percentage of entering the closed arm in anxiety+SNAP94847 group were significantly increased(P<0.05).Compared with control group,the catalase(CAT)activity and glutathione peroxidase(GSH-Px)content in anxiety rats were significantly decreased,while myeloperoxidase(MPO)activity and the contents of malondialdehyde(MDA),tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)were increased significantly(P<0.05).Microinjection of SNAP94847 into VTA significantly reduced gastric mucosal inflammation and injury in the rats(P<0.05).Compared with sham lesion+SNAP94847 group,the CAT activity and GSH-Px content in electrical lesion+SNAP94847 group were significantly decreased(P<0.05),while MPO activity and the contents of MDA,TNF-αand IL-6 were significantly increased(P<0.05).CONCLUSION:SNAP94847,an antagonist of MCHR1,may be involved in regulating stress-induced gastric injury and anxiety-like behavior in rats through MCHR signaling pathway of VTA-DMV.