瞬时受体电位通道家族M8亚型在大鼠偏头痛发病机制中的作用

Role of transient receptor potential melastatin 8 channels in migraine mechanism in rats

摘要:

目的 通过检测瞬时受体电位通道家族M8(TRPM8)亚型在偏头痛模型大鼠三叉神经组织中的表达变化探讨TRPM8在大鼠偏头痛发病机制中的作用。方法 将20只雄性Sprague-Dawley(SD)大鼠随机分为空白对照组和模型组, 每组10只。采用颈背部每周1次皮下注射硝酸甘油(10 mg/kg)建立无先兆性偏头痛大鼠模型, 共5周; 对照组则用生理盐水代替硝酸甘油行皮下注射。最后一次皮下注射4 h后, 对各组大鼠行行为学评分, 而后采集两组大鼠颅底三叉神经节, 采用免疫组化法检测两组三叉神经节中谷氨酸受体(NMDAR)的表达变化; 采用免疫荧光检测法观察两组三叉神经节中蛋白激酶A(PKA)的表达; 采用western blot法检测TRPM8蛋白在两组中的表达情况。结果 模型组大鼠在建模过程中每周的行为学评分均高于对照组(P<0.05)。模型组中NMDAR、PKA及TRPM8表达水平均高于对照组(P<0.01)。行为学评分与TRPM8表达水平呈正相关(r=0.822, P<0.01); NMDAR与TRPM8表达水平亦呈正相关(r=0.794, P<0.01)。结论 TRPM8可能参与了偏头痛的发病机制, 并且可能是通过NMDAR途径实现。

Abstract:

Objective To investigate the role of transient receptor potential melastatin 8 (TRPM8) channels in migraine mechanism in rats by measuring the changes in expression of TRPM8 in the trigeminal nerve of rats with migraine. Methods Twenty male Sprague-Dawley rats were randomly and equally divided into a blank control group and a model group. Nitroglycerin (10 mg/kg) was injected subcutaneously in the back of the neck once a week for 5 weeks, to prepared a rat model of migraine without aura. Normal saline was injected subcutaneously instead of nitroglycerin in the control group. At 4 hours after the final injection, behavior scoring of all rats was performed, and then the trigeminal nerve ganglions of rats in both groups were collected for measurement of expression of N-methyl-D-aspartate receptor (NMDAR), protein kinase A (PKA), and TRPM8 using immunohistochemical staining, immunofluorescence, and Western blot, respectively. Results The behavior score in each week during the rat model preparing was significantly higher in the model group than in the control group (P<0.05). The expression of NMDAR, PKA, and TRPM8 in the model group was significantly higher than in the control group (P<0.01). Both the behavior score and the expression of NMDAR were positively correlated with the expression of TRPM8 (r=0.822 and 0.794 respectively; P<0.01). Conclusions TRPM8 may be involved in migraine mechanism probably by activation of the NMDAR pathway.