NLRP3炎性小体在慢性偏头痛小鼠三叉神经脊束尾核的表达及作用

The expression and role of NLRP3 in?ammasome in trigeminal nucleus caudalis of mice with chronic migraine

摘要:

目的：观察炎性小体NLRP3（Nod-like receptor protein 3 inflammasome）在慢性偏头痛小鼠三叉神经脊束尾核（trigeminal nucleus caudalis, TNC）中的表达变化，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5组，生理盐水对照组（n=16），模型组（n=16），模型+溶剂组（n=8），模型+NLRP3抑制剂5mg/kg组（n=8），模型+NLRP3抑制剂10mg/kg组（n=8）。采用腹腔隔日重复注射硝酸甘油（nitroglycerin, NTG）建立慢性偏头痛小鼠模型。使用Von Frey test测定小鼠眶周和后足机械痛阈值。Western blot检测NLRP3及神经元活化标志蛋白p-ERK的表达变化，免疫荧光检测NLRP3在TNC的定位情况。结果：反复腹腔注射NTG后，小鼠眶周和后足的机械痛阈显著降低，而TNC部位的NLRP3和p-ERK蛋白表达显著增加。使用NLRP3的小分子抑制剂MCC950可以显著提高小鼠眶周和足底机械痛阈值，降低p-ERK的表达。荧光染色显示NLRP3与小胶质细胞共定位。结论：本研究表明TNC部位NLRP3炎性小体上调，可能通过影响神经元活化状态参与慢性偏头痛的病理生理过程。

Abstract:

Objective: To investigate the role of NLRP3 in?ammasome within trigeminal caudalis (TNC) in the pathophysiological process of a mouse model of chronic migraine (CM). Methods: male C57BL6/J mice were randomly divided into 5 groups: saline group (n=16), CM group (n=16), CM+PBS group (n=8), CM+MCC950 (5mg/kg) group (n=8) and CM+MCC950 (10mg/kg) group (n=8). We repeatedly intraperitoneal (i.p) injected the nitroglycerin (NTG) in awake mice to mimicking CM. Mechanical pain threshold of periorbital region and hind paw was detected by von Frey test. Western blotting was performed to detect the expression of NLRP3 and p-ERK protein in TNC. Localization of NLRP3 in TNC was detected by immunofluorescence methods. Results: Repeated injection of NTG decreased pain threshold in the periorbital region and hind paw (P < 0.05), and up-regulated the expression of NLRP3 and p-ERK in TNC (P < 0.05). Furthermore, inhibition of NLRP3 by MCC950 relieved the hyperalgesia, and reduced the expression of p-ERK. Immunofluorescence staining revealed that NLRP3 expressed in microglia in TNC. Conclusion: These data indicate that the up-regulation of NLRP3 in?ammasome in TNC may be involved in the pathophysiological process of hyperalgesia in CM by affecting the activation status of neurons.