大鼠三叉神经根区慢性压迫损伤对neuroligin-2表达的影响

Effects of trigeminal root chronic compression injury on the expression of neuroligin-2 in the trigeminal root entry zone in the rat

目的:研究神经连接蛋白2(NL2)在三叉神经痛发病中的作用。方法:将实验大鼠随机分成假手术组(sham)和三叉神经痛模型组(TN),TN组大鼠采用经眶下裂逆行颅内插管慢性压迫三叉神经根区(TREZ)的方法建立TN大鼠模型,应用免疫荧光组织化学染色方法检测NL2与星形胶质细胞标记物胶质纤维酸蛋白(GFAP)、少突胶质细胞标记物髓鞘碱性蛋白(MBP)在大鼠TREZ的表达情况,再用Western Blot方法检测NL2在TREZ的表达变化。结果:TREZ慢性压迫损伤后,TN组大鼠术后第7 d开始出现口面部机械痛阈值下降并持续到术后第28 d,明显低于假手术组和基础痛阈值;NL2表达于TREZ的胶质细胞,在三叉神经压迫损伤后NL2的表达显著增加;NL2在TREZ中枢端与GFAP阳性的星形胶质细胞大量共表达,而仅与MBP阳性的少突胶质细胞少量共表达。结论:大鼠三叉神经根慢性压迫损伤能诱导TREZ内NL2表达增加,可能是TN大鼠模型TREZ内星形胶质细胞大量增生和导致口面部机械痛痛敏的原因之一。

Objective:To study the effects of neuroligin-2(NL2)in the pathogenesis of trigeminal neuralgia(TN)of rat.Methods:Rats were randomly divided into sham group and TN group.The TN animal model was established by retrograde insertion a filament from the inferior orbital fissure to intracranial trigeminal root entry zone(TREZ)for chronic compression injury.Immunofluorescence histochemical staining for NL2 and astrocytes marker glial fibers acid protein(GFAP)in the TREZ were used in this study,and oligodendrocytes marker myelin basic protein(MBP)expression in the TREZ were studied both in the sham group and TN rats.The expression of NL2 in the TREZ were also performed by using Western Blot method.Results:After TREZ chronic compression injury,the threshold of orofacial mecha nical pain in TN group decreased from post-operation day 7 to 28,which was significantly lower than the threshold of sham group and baseline pain threshold.The NL2 expressed in glial cells in the TREZ region,and the expression of NL2 protein was significantly increased after the trigeminal nerve compression injury.In the central side of TREZ,NL2 mainly coexpressed with GFAP-positive astrocytes,and only a few NL2 co-expressed with MBP-positive oligodendrocytes.Conclusion:The increased expression of NL2 induced by chronic compression injury of the trigeminal nerve root might affect the proliferation of astrocytes in TREZ region,which may be involve in the orofacial mechanical pain sensitivity of TN rat model.