Objective: To observe the effect of electroacupuncture (EA) at "Ciliao" (BL 32) and "Huiyang" (BL 35) on the pain, urodynamic and the expressions of transient receptor poteintial vanilloid 1 (TRPV1) and P2X3 receptors in bladder of rats with interstitial bladder (IC), and to explore the possible mechanism on EA for IC.
Methods: A total of 24 Wistar female rats were randomly divided into a blank group, a model group and an EA group, 8 rats in each group. In the model group and the EA group, IC model was established by intraperitoneal injection of cyclophosphamide by 150 mg/kg at once. EA was applied at "Ciliao" (BL 32) and "Huiyang" (BL 35) in the EA group for 20 min, with continuous wave, 30 Hz in frequency, once a day for 3 consecutive days. Mechanical pain threshold of bladder and urodynamic indexes (first urination time, bladder effective volume and urination pressure) were observed after model establishment and after intervention, the expressions of TRPV1 and P2X3 receptors in the bladder were detected by Western blot.
Results: After model establishment, the mechanical pain threshold of bladder was decreased in the model group and the EA group compared with that in the blank group (P<0.01). After intervention, the mechanical pain threshold of bladder in the model group was lower than the blank group (P<0.01), and that in the EA group was higher than the model group (P<0.01). The urodynamic of the rats in the blank group was normal, obvious abnormal contraction during the filling period of bladder was found in the rats of the model group, while no abnormal contraction during the filling period was found in the rats of the EA group. After model establishment, in the model group and the EA group, the first urination time was earlier than the blank group (P<0.01), while bladder effective volume and urination pressure were lower than the blank group (P<0.01). After intervention, in the model group, the first urination time was earlier than the blank group (P<0.01), while bladder effective volume and urination pressure were lower than the blank group (P<0.05); in the EA group, the first urination time was later than the model group (P<0.05), while bladder effective volume and urination pressure were higher than the model group (P<0.05). Compared with the blank group, the protein expressions of TRPV1 and P2X3 receptors in bladder were up-regulated in the model group (P<0.01); compared with the model group, the protein expressions of TRPV1 and P2X3 receptors in bladder were down-regulated in the EA group (P<0.05).
Conclusion: EA can relieve bladder pain and improve urodynamic in IC rats. The mechanism may be related to the down-regulation on the expressions of TRPV1 and P2X3 receptors and the further inhibition on the abnormal input of bladder signal.
目的：观察电针“次髎”“会阳”对间质性膀胱炎（IC）模型大鼠疼痛、尿动力学及膀胱组织瞬时受体电位1（TRPV1）、P2X3受体表达的影响，探讨电针治疗IC的可能作用机制。方法：将24只Wistar雌性大鼠随机分为空白组、模型组和电针组，每组8只。模型组及电针组大鼠予一次性腹腔注射环磷酰胺（150 mg/kg）制备IC模型。电针组大鼠予电针“次髎”“会阳”干预，连续波，频率30 Hz，每次20 min，每日1次，连续干预3 d。分别于造模后及干预后检测各组大鼠膀胱机械疼痛阈值及尿动力学指标（初次排尿时间、膀胱有效容量和排尿压力）；Western blot法检测大鼠膀胱组织TRPV1、P2X3受体的蛋白表达。结果：造模后，模型组、电针组大鼠膀胱机械疼痛阈值低于空白组（P<0.01）；干预后，模型组大鼠膀胱机械疼痛阈值低于空白组（P<0.01），电针组膀胱机械疼痛阈值高于模型组（P<0.01）。空白组大鼠尿动力正常，模型组大鼠膀胱充盈期出现明显异常收缩，而电针组膀胱充盈期未见明显异常收缩。造模后，模型组、电针组初次排尿时间早于空白组（P<0.01），膀胱有效容量、排尿压力低于空白组（P<0.01）。干预后，模型组初次排尿时间早于空白组（P<0.01），膀胱有效容量、排尿压力低于空白组（P<0.01）；电针组初次排尿时间晚于模型组（P<0.05），膀胱有效容量、排尿压力高于模型组（P<0.05）。与空白组比较，模型组大鼠膀胱组织TRPV1、P2X3受体蛋白表达上调（P<0.01）；与模型组比较，电针组大鼠膀胱组织TRPV1、P2X3受体蛋白表达下调（P<0.05）。结论：电针能缓解IC大鼠膀胱疼痛，改善尿动力学，其机制可能与下调膀胱组织TRPV1和P2X3受体表达，抑制膀胱信号异常传入有关。.
Keywords: P2X3; electroacupuncture; interstitial cystitis; transient receptor potential vanilloid 1 (TRPV1); urodynamic.