siRNA下调SCN9A表达对慢性炎性痛模型大鼠疼痛的影响

Effect of down-regulation of SCN9A expression by siRNA on pain in rats with chronic inflammatory pain

目的探讨siRNA靶向下调SCN9A表达对慢性炎性痛模型大鼠疼痛行为学的影响。方法将18只雄性SPF级SD大鼠随机分成3组,每组6只。空白组不作任何处理,模型组、干预组于右后足皮下给予0.1 mL完全弗氏佐剂建立慢性炎性痛模型,模型组于蛛网膜下腔注射空白慢病毒载体,干预组于蛛网膜下腔注射SCN9A siRNA慢病毒载体(LV-SCN9A-RNAi)。于建模前及建模后1 d、2 d、5 d、8 d、12 d观察大鼠右后肢机械刺激缩足反射阈值(PMWT)和热刺激缩足反射潜伏期(PWTL)。于建模后第13天处死大鼠,取L_(4)~L_(5)背根神经节组织,采用RT-PCR、Western blot检测SCN9A mRNA及蛋白表达水平,同时Western blot检测L_(4)~L_(5)脊髓OX42、GFAP蛋白表达水平。结果各组大鼠建模前PMWT、PWTL比较差异均无统计学意义(P>0.05),模型组、干预组建模后各时间点PMWT、PWTL均明显低/短于空白组(P<0.05)。干预组建模后2 d、5 d、8 d、12 d的PMWT、PWTL明显高/长于模型组,差异均有统计学意义(P<0.05)。干预组SCN9A mRNA表达水平高于空白组,低于模型组,差异均有统计学意义(P<0.05)。干预组SCN9A、GFAP、OX42蛋白表达水平高于空白组,低于模型组,差异均有统计学意义(P<0.05)。结论蛛网膜下腔注射LV-SCN9A-RNAi可抑制大鼠背根神经节SCN9A表达,从而有效改善慢性炎性痛模型大鼠的疼痛及疼痛行为学。

Objective To investigate the effect of siRNA targeting down-regulation of SCN9A expression on the pain behavior of rats with chronic inflammatory pain.Methods A total of 18 male SPF grade SD rats were randomly divided into three groups,each group with 6 rats.The blank group did not do any treatment,the model group and the intervention group were given 0.1 mL of complete Freund’s adjuvant subcutaneously into the right hind foot to establish chronic inflammatory pain model,the model group was injected with a blank lentiviral vector into the subarachnoid space,and the intervention group was injected with the SCN9A siRNA lentiviral vector(LV-SCN9A-RNAi)into the subarachnoid space.The paw mechanical withdrawal threshold(PMWT)and paw withdrawal thermal latency(PWTL)of the right hind limb of the rats before modeling and 1 day,2 days,5 days,8 days and 12 days after modeling were observed.The rats were killed 13 days after modeling to obtain the tissues of L_(4) to L_(5) dorsal root ganglion.The SCN9A mRNA and protein expression levels were detected by RT-PCR and Western blot,and the protein expression levels of spinal marrow OX42 and GFAP were detected.Results There was no significant difference in the PMWT or PWTL before modeling among the three groups(P>0.05),the PMWT and PWTL in the model group and the intervention group at each time point after modeling were significantly lower/shorter than those in the blank group(P<0.05).The PMWT and PWTL 2 days,5 days,8 days,12 days after modeling of the intervention group were significantly higher/longer than those of the model group,with statistically significant differences(P<0.05).The expression level of SCN9A mRNA in the intervention group was higher than that in the blank group,and lower than that in the model group,with statistically significant differences(P<0.05).The protein expression levels of SCN9A,GFAP and OX42 in the intervention group were higher than those in the blank group,and lower than those in the model group,with statistically significant differences(P<0.05).Conclusion Subarachnoid injection of LV-SCN9A-RNAi can inhibit the expression of SCN9A in rats dorsal root ganglion,thereby effectively improving pain and pain behavior in rats with chronic inflammatory pain.