鞘内注射DREAM-shRNA对神经病理性痛大鼠的镇痛效应

目的 评价鞘内注射转录因子下游调控元件拮抗因子-短发夹RNA(DREAM-shRNA)对神经病理性痛大鼠的镇痛效应.方法 健康雄性SD大鼠,体重280-320g,采用坐骨神经慢性缩窄性损伤(CCI)法建立大鼠神经病理性痛模型,于CCI后第3天鞘内置管.取鞘内置管成功的大鼠24只,随机分为4组,每组6只,假手术组(Sham组):仅暴露坐骨神经,不结扎;神经病理性痛组(NP组):于CCI后第8天鞘内注射生理盐水10μl;RNA干扰组(RNAi组):于CCI后第8天鞘内注射含DREAM-shRNA的慢病毒5μl、生理盐水5μl;空白载体组(BV组):于CCI后第8天鞘内注射慢病毒空白载体5μl、生理盐水5μl,连续注射7d.于CCI前1d(基础状态)、CCI后第7～14天(T1-8)测定热痛阈和机械痛阈,于CCI后第15天测定脊髓背角绿色荧光蛋白(GFP)的表达水平.结果 与基础值比较,NP组和BV组热痛阈降低,Sham组T1-4时热痛阈降低,RNAi组T1-4,6时热痛阈降低,4组CCI后各时点机械痛阈降低(P<0.05或0.01);与T1时比较,NP组和BV组其余时点热痛阈和机械痛阈降低.RNAi组T3-5,时热痛阈降低,T1时热痛阈和机械痛阈升高(P<0.05或0.01);与Sham组比较.NP组和BV组热痛阈和机械痛阈降低,RNAi组T2时机械痛阈降低,T5时升高(P<0.05),热痛阈差异无统计学意义(P>0.05);与NP组比较.RNAi组热痛阈和机械痛阈升高(P<0.05).仅RNAi组脊髓背角有GFP表达,其余3组脊髓背角未见GFP表达.结论 鞘内连续注射DREAM-shRNA可在一定程度上缓解大鼠神经病理性痛.

Analgesic effect of intrathecal DREAM-shRNA in rats with neuropathic pain

Objecfive To investigate the analgesic effect of intrathecal(IT)DREAM.short hairpin RNA (shRNA)in rats with neuropathic pain.Methods Healthy male SD rats weighing 280-320 g were used in this study.Neuropathic pain was induced by chronic constrictive iniury(CCI)to sciatic nerve.A microspinal catheter W&q inserted into subaraehnoid space according to Yak8h method at day 3 after CCI.Twenty.four rats in which IT catheter was successfully implanted were randomly divided into 4 groups(n=6 each):group Ⅰsham operation (S).group Ⅱ neuropathic pain(NP),groupⅢRNA interference(BNAi)and groupⅣblank vector(BV).Lentivims with DREAM-shRNA 5μl was injected IT at day 8 after CCI in group RNAi(Ⅲ).Blank vector 5 μl was injected IT once a day for 7 days,starting from the day 8 after CCI in group BV(Ⅳ).The thermal plan threshold and mechanical pian threshold were measured at day 1 before CCI(To,baseline)and at day 7-14 after CCI(T1-8).The animals were killed at day 15 after CCI.The lumbar segment of the spinal cord(L4-6)was removed for determination of expression of green fluorescent protein(GFP)in the dorsal hom of the spihal cord by immune-fluorescent method.Results The thermal threshold was signillcanfly decreased at T1-4 as compared with the baseline at To in all 4 groups and returned to the baseline levels at T5-8 in group S and RNAi ( group Ⅰ and Ⅱ ) but remained low in group NP (Ⅱ ) and BV (Ⅳ ). The mechanical pian threshold was significantly decreased after CC1/sham operation and was significanty higher at T8 in group BNAi than in other 3 groups. The green fluorescence was observed in group BNAi but not in other 3 groups. Conclusion IT DBEAN-shRNA can ameliorate hyperalgesia in rats with neuropathic pain.