南方医科大学学报

南方医科大学学报 ›› 2019, Vol. 39 ›› Issue (10): 1160-.doi: 10.12122/j.issn.1673-4254.2019.10.05

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大鼠三叉神经痛觉传入通路的电生理检测和咬合干扰的影响

王云，钱金萍，顾亚茹，陈传俊，汪萌芽   

  • 出版日期:2019-10-20 发布日期:2019-10-20

Electrophysiological monitoring of pain afferent pathway of the trigeminal nerve and its functional plasticity in response to occlusal interference in rats

  • Online:2019-10-20 Published:2019-10-20

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摘要： ：目的通过建立电刺激大鼠三叉神经节（TG），记录三叉神经脊束核尾侧亚核（SPVC）生物电活动的技术，观察咬合干扰对 三叉神经痛觉传入通路功能、SPVC神经元兴奋性的影响。方法取雄性健康Wistar大鼠（体质量250~280 g）20只，随机均分为 对照组和模型组（n=10）。模型组大鼠用光固化流动树脂粘接法在大鼠右上第一磨牙牙合面制造咬合高点造模，持续咬合干扰 30 d，期间用von Frey尼龙毛检测咬肌压痛并进行痛敏评分鉴定。然后在乌拉坦麻醉下同步记录SPVC生物电活动和心电、呼 吸肌肌电、体温等多项生理指标，并观察电刺激TG对各项指标的影响。结果与对照组相比，模型组大鼠在造模后1 d即开始出 现咬肌的痛敏评分升高，7 d后达到高峰；咬合干扰30 d后模型组大鼠SPVC自发放电频率增加（P<0.05）；给予TG不同强度的 单脉冲刺激（0.5~8.0 mA，0.1~0.2 ms），在两组大鼠SPVC均可诱发放电性反应，其幅值具有刺激强度依赖性（P<0.05），在4 mA 和8 mA强度模型组大鼠的反应幅值与对照组相似（P>0.05）；给予TG高频串刺激（0.2 ms，1 mA，30 s，100 Hz），在两组大鼠 SPVC均引发放电频率呈一过性升高，但仅模型组刺激后放电频率升高有统计学意义（P<0.05）。结论大鼠三叉神经痛觉传入 通路的活动可用电刺激TG记录SPVC生物电活动的方法进行检测，咬合干扰可能提高该通路的敏感性和SPVC神经元的兴奋 性，导致通路的神经可塑性变化。

Abstract: Objective To observe the effect of occlusal interference on the afferent pathway of the trigeminal nerve and neuronal excitability in the trigeminal subnucleus caudalis (SPVC) of rats by electrical stimulation of the trigeminal ganglion (TG) and extracellular recordings of SPVC activities. Methods Twenty male Wistar rats were randomly divided into control group and model group (n=10). In the model group, occlusal interference for 30 consecutive days was induced using light-cured flowable resin on the right maxillary molars. During occlusal interference, the pain sensitivity was scored with von Frey Fibers in the masseter. Simultaneous recordings of electrical activities from the SPVC, electrocardiogram, body temperature and electromyogram of the breath muscles of the anesthetized rats were performed, and the responses evoked by electrical stimulation of the TG were analyzed. Results Compared with the control rats, the rats in the model group showed significantly increased pain sensitivity scores (P<0.05) and increased spontaneous discharge frequency of the SPVC (P<0.05). The amplitude of the SPVC responses induced by electrical stimulation of the TG showed stimulus intensity-dependent changes (P<0.05), and the amplitude evoked by 4 mA and 8 mA stimulation was similar between the model group and the control group (P>0.05). Train stimulation (0.2 ms, 1 mA, 30 s, 100 Hz) of the TG significantly increased the discharge frequency of the SPVC only in the rats in the model group (P<0.05). Conclusion The functional activities of the pain afferent pathway of the trigeminal nerve can be electrophysiologically monitored by electrical stimulation of the TG and extracellular recordings of SPVC activities in rats. Occlusal interference can increase the excitability of the neurons in the SPVC and enhance their sensitivities to TG afferent activation, suggesting the neural plasticity of the pain afferent pathway.