NADPH氧化酶介导的小胶质细胞活化在神经病理性疼痛和抑郁共病中的作用

Role of NADPH oxidase-mediated activation of microglia in the comorbidity of neuropathic pain and depression

目的观察神经病理性疼痛和抑郁共病中磷酸酰胺腺嘌呤二核苷酸(NADPH)氧化酶及小胶质细胞的变化,并探讨其相关机制。方法采用保留性坐骨神经损伤模型(SNI模型)。健康成年雄性SD大鼠44只,随机分为四组:假手术+溶剂组(SV组)、假手术+夹竹桃麻素(APO)组(SA组)、SNI+溶剂组(SNV组)、SNI+APO组(SNA组),每组11只。SA组和SNA组术前24h及术前1h腹腔注射APO 15mg/kg,以后每天注射1次直至SNI术后14d;其余两组在相同时点注射等容量溶剂。术前1d和术后7、14d进行机械缩足反射阈值(MWT)测试,术后14d进行旷场实验、强迫游泳实验和糖水偏好实验等行为学测试。行为学后2h取大鼠前额叶皮层组织,采用Western blot法检测gp91^(phox)的含量,免疫荧光共标法检测Iba1和gp91^(phox)的表达量。结果与SV、SA、SNA组比较,SNV组MWT明显降低,强迫游泳不动时间明显延长,糖水消耗比例明显减少,gp91^(phox)含量明显增多(P<0.05)。与SV、SA、SNA组比较,SNV组Iba1和gp91~(^(phox))表达量增多。旷场实验中,四组探索总路程差异无统计学意义;糖水偏好实验中,四组总液体消耗量差异无统计学意义。结论神经病理性疼痛可导致抑郁样行为,并引起前额叶皮层的NADPH氧化酶活化;NADPH氧化酶抑制剂APO可减轻疼痛和抑郁样行为,其机制可能与抑制小胶质细胞活化有关。

Objective To observe the variation of nicotinamide adenine dinucleotide phosphate（NADPH）oxidase and microglia in the comorbidity of neuropathic pain and depression and discuss the related mechanism.Methods The spared nerve injury model was used.Forty-four male adult Sprague Dawley rats were randomly divided into the following four groups（n=11each）：sham＋vehicle group（group SV）,sham＋APO group（group SA）,SNI＋vehicle group（group SNV）,SNI＋APO group（group SNA）.In groups SA and SNA,rats were intraperitoneally injected with apocynin（APO）15mg/kg 24 hours and 1hour before SNI and continued once daily until the 14 th day.The rats in the other two groups received the equal volume of vehicle.The mechanical withdrawal threshold（MWT）was tested 1day before SNI and 7days and 14 days after SNI,and the open field test,the forced swimming test and the sucrose preference test were performed 14 days after SNI.The prefrontal cortex were collected 2hour after the behavior tests.The expression of gp91 ^（phox） was detected by Western blot and the expression of Iba1 and gp91^（phox） were detected by double-immunofluorescance staining.Results The reduced MWT,the increased immobility time,the decreased sucrose consumption and the increased content of gp91 ^（phox） were observed in group SNV compared with groups SV,SA and SNA（P〈0.05）.The expression of Iba1 and gp91^（phox） were increased in group SNV.The total travel distance in the open field test and the total liquid consumption in the sucrose preference test had no significant difference among the four groups.Conclusion Neuropathic pain may induce depressive behaviors and activate NADPH oxidase in the prefrontal cortex.Moreover,the inhibition of NADPH oxidase by APO can alleviate neuropathic pain and depression,which is potentially related to the activation of microglia.