星型胶质细胞Kir4.1在慢性偏头痛小鼠三叉神经脊束尾核的表达及作用

The role of Astrocytic Kir4.1 in trigeminal nucleus caudalis of mice with chronic migraine

摘要:

目的：观察星形胶质细胞内向整流钾通道4.1（inwardly rectifying potassium channel 4.1, Kir4.1）在慢性偏头痛（chronic migraine, CM）模型小鼠三叉神经脊束尾核（trigeminal nucleus caudalis, TNC）的表达变化，并探讨其在慢性偏头痛中的作用。方法：C57BL6/J雄性小鼠随机分为3组，分别为生理盐水对照组，慢性偏头痛组和频发慢性偏头痛组（frequent chronic migraine, FCM），通过反复注射硝酸甘油 （nitroglycerin, NTG)建立CM小鼠模型（隔日注射NTG）和FCM小鼠模型（每日注射NTG）；Aldh1l1-CreERT2小鼠靶向TNC脑区过表达或敲低星形胶质细胞Kir4.1后，反复注射NTG建立CM小鼠模型，von-Frey纤维丝评估后爪底及眶周机械阈值，通过使用免疫荧光实验检测降钙素基因相关肽（calcitonin gene-related peptide, CGRP)、c-Fos蛋白和Kir4.1的表达。结果：与CON组相比，FCM组与CM组模型小鼠痛觉阈值显著降低，TNC脑区CGRP、Kir4.1表达下降，c-Fos表达增加。过表达Kir4.1小鼠TNC脑区的CGRP蛋白表达显著减少且机械痛阈阈值明显增高，敲低Kir4.1组小鼠则相反。结论：本研究表明TNC部位星型胶质细胞Kir4.1可能参与慢性偏头痛发生发展的病理生理过程。

Abstract:

Objective: To observe the expression changes of inwardly rectifying potassium channel 4.1 (Kir4.1) in the trigeminal nucleus caudalis (TNC) of chronic migraine (CM) mouse models and explored its role in CM. Methods: Male C57BL6/J mice were randomly divided into three groups: saline control, CM group, and frequent chronic migraine group (FCM). CM models (injection of NTG on alternate days) and FCM models (injection of NTG daily) were established via repeated nitroglycerin (NTG) injections. In Aldh1l1-CreERT2 mice with astrocytic Kir4.1 overexpression or knockdown in the TNC, repetitive NTG injections were administered to establish the CM mouse model. Mechanical thresholds of the hindpaw and periorbital area were assessed using von-Frey filaments. The expression of calcitonin gene-related peptide (CGRP), c-Fos, and Kir4.1 was detected via immunofluorescence. Results: Compared to control group, FCM and CM mice showed lower pain thresholds and increased CGRP and c-Fos expression in the TNC, along with reduced Kir4.1 levels. Kir4.1 overexpression decreased CGRP expression in the TNC and the mechanical threshold was significantly increased, while Kir4.1-knockdown group has the opposite effect. Conclusion: Astroglial Kir4.1 in the TNC may be involved in the pathophysiology of chronic migraine.