线粒体抗氧化对神经病理性疼痛大鼠TRPV1表达的影响

Effect of mitochondria-targeted antioxidant on TRPV1 expression in neuropathic pain rats

目的探讨线粒体抗氧化治疗对神经病理性疼痛(NP)大鼠脊髓水平瞬时感受器电位香草酸受体1(TRPV1)表达的影响。方法清洁级雄性SD大鼠120只,采用随机数字表法分为3组:假手术组(Sham组,n=40)、神经病理性疼痛组(NP组,n=40)、抗氧化治疗组(MT组,n=40)。NP组和MT组采用慢性坐骨神经结扎(CCI)制备NP模型。术后第7天MT组腹腔注射三苯基磷阳离子结合抗氧化剂(MT)0.7 mg/kg, Sham组和NP组腹腔注射生理盐水,1次/d,连续14 d。术前及术后第3、7、14、21天时测定机械缩足反应阈(MWT)和热缩足潜伏期(TWL),评价疼痛行为。术前及术后第3、7、14、21天取大鼠L4-6节段脊髓,采用Western blot法测定TRPV1的表达。结果与Sham组比较,NP组大鼠术后第3、7、14、21天MWT明显降低(P<0.05),TWL明显缩短(P<0.05),MT组大鼠术后第3、7天MWT明显降低(P<0.05),TWL明显缩短(P<0.05);与NP组比较,MT组大鼠术后第14、21天MWT明显升高(P<0.05),TWL明显延长(P<0.05)。与Sham组比较,NP组大鼠脊髓TRPV1表达在术后第7、14、21天明显增加(P<0.05), MT组大鼠术后第7天脊髓TRPV1表达明显增加(P<0.05);与NP组比较,MT组大鼠脊髓TRPV1在术后第14、21天明显降低(P<0.05)。结论线粒体抗氧化可以缓解NP大鼠的疼痛行为,可能与降低脊髓水平TRPV1表达有关。

Objective To evaluate the effect of mitochondria-targeted antioxidant on transient receptor potential cation channel,subfamily V,member 1(TRPV1) expression in neuropathic pain(NP) rats. Methods 120 male Sprague-Dawley rats were randomly divided into 3 groups ( n =40 each) using a random number table:sham operation group(Sham group),neuropathic pain group(NP group),mitochondrial antioxidant treatment group(MT group). Neuropathic pain was induced by chronic constriction injury in NP and MT groups. Starting from 7th day after operation,mito-tempo (triphenylphosphine cation combined with antioxidant) 0.7 mg/kg in 1ml of normal saline was injected intraperitoneally once a day for 14 consecutive days in MT group,and the equal volume of normal saline was given once a day for 14 consecutive days in Sham and NP groups. On 1 day before operation and 3,7,14 and 21 days after operation,the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured. Lumbar 4-6 segments of the spinal cord were harvested to detect the expression of TRPV1(by Western blot) before operation and on days 3,7,14 and 21 after operation. Results Compared with group Sham,the MWT and TWL in NP group were significantly decreased on the 3rd,7th,14th and 21st day after operation( P <0.05),the MWT and TWL in MT group were significantly decreased on the 3rd and 7th day after operation( P <0.05);Compared with group NP,the MWT and TWL in MT group were significantly increased on the 14th and 21st day after operation( P <0.05). Compared with group Sham,the expression of TRPV1 in NP group was significantly increased on the 7th,14th and 21st day after operation( P <0.05),the expression of TRPV1 in MT group was significantly increased on the 7th day after operation( P <0.05);Compared with group NP,TRPV1 expression in MT group was significantly deceased on the 14th and 21st day after operation( P <0.05). Conclusion The mechanism by which mitochondrial antioxidant treatment increases behavior threshold may be related to TRPV1 expression reduction.