慢性胃食管反流大鼠背根神经节中辣椒素受体1和大麻素受体的表达

Expressions of Vanilloid Receptor 1 and Cannabinoid Receptors in Dorsal Root Ganglion in Rats with Chronic Gastroesophageal Reflux

背景:食管痛觉高敏参与胃食管反流病(GERD)的发病,而辣椒素受体1(TRPV1)和大麻素系统的激活在疼痛调控中发挥双向作用。目的:检测慢性胃食管反流大鼠相应节段背根神经节(DRG)中TRPV1和大麻素受体(CB1、CB2)的表达情况,探讨两者在GERD中的作用。方法:雄性Sprague-Dawley大鼠随机分为反流组(R组)、对照组(S组)。采用胃底结扎联合幽门限制法构建慢性胃食管反流模型。采用免疫荧光法和蛋白质印迹法检测大鼠DRG中TRPV1和CB1、CB2的表达,并分析TRPV1蛋白表达与CB1、CB2蛋白表达的相关性。结果:免疫荧光法示R组DRG中TRPV1表达较S组显著上调(905.24±134.82对648.43±135.13,P=0.000);而CB1(677.06±123.75对836.89±101.00,P=0.013)、CB2(513.99±79.80对709.63±43.25,P=0.000)表达显著下调。蛋白质印迹法亦显示,R组TRPV1蛋白表达显著高于S组(0.98±0.01对0.64±0.09,P=0.001),CB1(0.86±0.05对0.96±0.06,P=0.013)、CB2(0.75±0.03对0.81±0.05,P=0.019)蛋白表达显著低于S组。TRPV1蛋白表达与CB1蛋白表达呈负相关(r=-0.836,P=0.001),而与CB2蛋白表达无关(r=-0.351,P=0.263)。结论:慢性胃食管反流大鼠中TRPV1蛋白表达上调与CB1蛋白表达下调密切相关,酸在调节受体分子中起关键作用。

Background： Esophageal hyperalgesia is involved in the pathogenesis of gastroesophageal reflux disease （GERD）; vanilloid receptor 1 （TRPV1） and cannabinoid system play opposite roles in pain regulation. Aims： To determine the expressions of TRPV1 and cannabinoid receptors （CB1 and CB2） and their possible roles in dorsal root ganglion （DRG） in rats with chronic gastroesophageal reflux. Methods： Male Sprague-Dawley rats were randomly divided into reflux group （R group） and control group （S group）. The fundus of rat stomach was ligated and the pyloric sphincter was restricted to establish chronic gastroesophageal reflux model. The expressions of TRPV1, CB1 and CB2 in DRG were determined by immunofluorescence and Western blotting. Relationship of expression of TRPV1 protein with expressions of CB1, CB2 proteins was analyzed. Results： Immunofluorescence results showed that expression of TRPV1 in DRG was significantly up-regulated in R group than in S group （905.24±134.82 vs. 648.43±135.13, P=0.000）, while expressions of CB1 and CB2 were significantly down-regulated （CB1： 677.06±123.75 vs. 836.89±101.00, P=0.013; CB2： 513.99±79.80 vs. 709.63±43.25, P=0.000）. Western blotting assay showed that expression of TRPV1 protein was significantly increased in R group than in S group （0.98±0.01 vs. 0.64±0.09, P=0.001）, while expressions of CB1 and CB2 proteins were significantly decreased （CB1： 0.86±0.05 vs. 0.96±0.06, P=0.013; CB2： 0.75±0.03 vs. 0.81±0.05, P=0.019）. The TRPV1 protein expression was negatively correlated with CB1 protein expression （r=-0.836,P=0.001）, but was not correlated with CB2 protein expression （r=-0.351, P=0.263）. Conclusions： The increased TRPV1 protein expression is strongly correlated with decreased CB1 protein expression in rats with chronic gastroesophageal reflux, which indicates that acid plays a critical role in the regulation of these receptor molecules.