电针对慢性骨盆疼痛综合征大鼠疼痛阈值及疼痛相关因子表达的影响

Effect of electroacupuncture on pain threshold and expression of pain-related factors cyclooxygenase-2,prostaglandin E2andβ-endorphin in rats with chronic pelvic pain syndrome

目的:观察电针对慢性骨盆疼痛综合征(CPPS)大鼠疼痛的治疗作用,并探究其可能的作用机制。方法:雄性SD大鼠随机分为空白组、模型组、假手术组、假电针组、电针组,每组10只。采用前列腺两侧腹叶注射完全弗氏佐剂(CFA)50μL制备CPPS大鼠模型;假手术组仅在下腹部作切口,不注射CFA。电针组予“关元”“中极”“三阴交”“会阳”电针治疗,疏密波,频率2Hz/100Hz,电流强度以鼠尾稍微摆动而无明显挣扎为宜;假电针组予“关元”“中极”“三阴交”“会阳”皮下浅刺1mm,不连接电针仪。以上干预均每日1次,每次40min,每周治疗5d休息2d,连续4周。造模后每周测定大鼠后足机械痛阈值、热痛阈值;治疗后测定大鼠体质量、前列腺湿重、前列腺指数;HE染色法观察大鼠前列腺组织形态;酶联免疫吸附法检测大鼠前列腺组织匀浆中环氧合酶-2(COX-2)、前列腺素E2(PGE2)、β-内啡肽(β-EP)的含量。结果:与空白组、假手术组比较,模型组各时点足机械痛阈值、热痛阈值均明显降低(P<0.01)。与模型组比较,电针组治疗3、4个疗程后足机械痛阈值、热痛阈值均明显增高(P<0.01);假电针组痛阈值有升高趋势,但差异无统计学意义(P>0.05)。治疗4周后,与空白组、假手术比较,模型组前列腺出现明显病理改变,前列腺湿重、前列腺指数及前列腺组织中COX-2、PGE2含量明显升高(P<0.01),β-EP含量明显降低(P<0.01)。与模型组比较,电针组前列腺病理形态明显改善,前列腺湿重、前列腺指数及前列腺组织中COX-2、PGE2含量明显降低(P<0.01),β-EP含量明显升高(P<0.01);假电针组前列腺病理形态无明显改善,前列腺湿重、前列腺指数及前列腺组织中COX-2、PGE2、β-EP含量差异均无统计学意义(P>0.05)。结论:电针可改善CPPS大鼠的痛觉敏感性,其机制可能与降低疼痛相关因子COX-2、PGE2表达,提高疼痛相关因子β-EP表达有关。

Objective To explore the possible mechanism of electroacupuncture(EA)underlying improvement of chronic pelvic pain syndrome(CPPS).Methods Fifty SD rats were randomly divided into control,model,sham operation,EA and sham EA groups(n=10rats in each group).The CPPS model was established by injecting complete Freund’s adjuvant(CFA,50μL)into the ventral lobes of the prostate.EA(2Hz/100Hz)was applied to“Guanyuan”(CV4),“Zhongji”(CV3),“Sanyinjiao”(SP6)and“Huiyang”(BL35)once daily for 40min,5days a week for 4weeks,while rats in the sham EA group were treated with the same acupoints but without electrical stimulation.Mechanical pain threshold(MPT)and heat pain threshold(HPT)were measured before and after intervention.The body weight and prostate weight were measured and prostate index was calculated.Histopathological changes of prostate tissue were observed by HE staining.The levels of cycloxygenase-2(COX-2),prostaglandin E2(PGE2)andβ-endorphin(β-EP)in prostate tissue were detected by ELISA.Results Compared with the control and sham operation groups,the MPT and HPT were significantly lower(P<0.01),and the prostate weight,prostate index,the contents of PGE2and COX-2were significantly increased(P<0.01),while the content ofβ-EP was significantly decreased(P<0.01)in the model group.Compared with the model group,the MPT and HPT were significantly increased(P<0.01)after 3and 4courses of treatment,and the prostate weight,prostate index,the contents of PGE2and COX-2were significantly decreased(P<0.01),while the content ofβ-EP was significantly increased(P<0.01)in the EA group,rather than in the sham EA group(P>0.05).Conclusion EA can effectively relieve pain in CPPS rats,which may be related to its functions in downregulating COX-2and PGE2,and up-regulatingβ-EP.