电针合谷对牙髓痛大鼠模型三叉神经节和牙髓中P2X4受体的影响

Effect of Electroacupuncture on P2X4 Receptors in Trigeminal Ganglia and Dental Pulp in a Rat Model of Pulpalgia

目的观察电针合谷对实验性牙髓痛大鼠三叉神经节和牙髓中P2X4受体表达的影响.方法成年雄性SD大鼠42只,随机分为正常组(N组)、对照组(C组)、牙髓痛组(M组)、拮抗剂组(A组)、电针组(E组)、拮抗剂+电针组(AE组),每组7只.N组不做任何处理;C组在钻好的牙髓腔内注入与M组等量的生理盐水,浸润后将牙洞封闭;M组在钻好的牙髓腔内注入大肠杆菌内毒素(LPS),浸润后牙洞封闭;A组造模方法同M组,在注入LPS时,将A-317491同时注射进牙髓;E组同M组造模后,电针双侧合谷,留针30 min,每日1次,共治疗3次;AE组按A组造模后按E组方法治疗.每日治疗后观察大鼠的行为学变化及体质量变化,第4天处死所有大鼠,运用RT-PCR方法分别检测大鼠三叉神经节和牙髓中P2X4受体(mRNA)表达,比较各组P2X4受体mRNA相对表达量.结果 A组、E组、AE组行为学变化均显著低于M组(P<0.01);E组、AE组体质量差值均显著高于M组(P<0.01);AE组体质量差值显著高于A组和E组(P<0.01);E组体质量差值高于A组(P<0.05);E组、AE组三叉神经节和牙髓中P2X4受体mRNA表达量低于M组(P<0.01).结论 LPS诱导大鼠牙髓痛时三叉神经节和牙髓P2X4受体mRNA表达量增加,电针合谷可降低LPS诱导牙髓痛大鼠P2X4受体mRNA表达,这可能是电针合谷镇痛的机制.

Objective To investigate the effect of electroacupuncture at point Hegu (LI4) on the expression of P2X4 receptors in trigeminal ganglia and dental pulp in experimental pulpalgia rats. Method Forty-two male adult SD rats were randomized to normal (N), control (C), pulpalgia (M), antagonist (A), electroacupuncture (E) and antagonist+electroacupuncture (AE) groups, seven rats each. The N group was not treated. In the C group, normal saline of the same volume of as in the M group was infused into the drilled pulp cavity and the cavity was sealed after infiltration. In the M group, escherichia coli endotoxin (E-LPS) was infused into the drilled pulp cavity and the cavity was sealed after infiltration. In the A group, the modeling method was the same as in the M group and A-317491 was injected into the dental pulp when E-LPS was infused. In the E group, the modeling method was the same as in the M group and bilateral points Hegu were given electroacupuncture with the retention of the needles for 30 min, once daily for a total of three times. In the AE group, treatment was given according to the method in the E group after a model was made according to the method in the A group. Changes in behaviors and body weight were observed after daily treatment. All the rats were sacrificed on the fourth day. The expression of P2X4 receptors (mRNA) in rat trigeminal ganglia and dental pulp was determined using RT-PCR. The relative expression quantities of P2X4 receptor mRNA were compared between various groups. Result Behavioral changes were significantly smaller in the A, E and AE groups than in the M group (P<0.01). The difference value of body weight was significantly higher in the E and AE groups than in the M group (P<0.01). The difference value of body weight was significantly higher in the AE groups than in the A and E group (P<0.01). The difference value of body weight was significantly higher in the E group than in the A group (P<0.05). The expression of P2X4 receptor mRNA in trigeminal ganglia and dental pulp was significantly lower in the E and AE groups than in the M group (P<0.01). Conclusion The expression of P2X4 receptor mRNA in trigeminal ganglia and dental pulp increases when E-LPS induces pulpalgia in rats. Electroacupuncture at point Hegu can reduce the expression of P2X4 receptor mRNA in E-LPS-induced pulpalgia rats. This may be the analgesic mechanism of electroacupuncture at point Hegu.