鞘内注射DNMT1-siRNA对CCI大鼠行为学和脊髓SOCS1、p-ERK、p-CREB表达的影响

目的探讨DNMT1在大鼠神经病理性痛中的作用及可能机制。方法清洁级健康雄性SD大鼠32只,体重200~250g,随机分为四组:假手术组(S组)、神经病理性痛组(CCI组)、CCI+DNMT1-siRNA组(CDS组)和CCI+control-siRNA组(CCS组),每组8只。CDS组在术后7、8、9d连续鞘内注射DNMT1-siRNA(2μg/10μl),CCS组注射等体积的对照序列siRNA(control-siRNA)。分别在术前1d,术后3、5、7、9、12和14d测定大鼠的机械缩足阈值(MWT)和热缩足反射潜伏期(TWL),术后14d测完行为学后处死大鼠,取L_4~L_6脊髓腰膨大节段,采用Western blot技术检测脊髓SOCS1、p-ERK、p-CREB的表达水平。结果术后3、5、7、9、12和14dCCI组和CCS组大鼠的MWT明显低于,TWL明显短于S组(P0.05);术后9、12、14dCDS组大鼠MWT明显高于,TWL明显长于CCS组(P0.05);术后14dCCI组和CCS组SOCS1表达明显低于S组和CDS组,pERK、p-CREB表达明显高于S组和CDS组(P0.05)。结论鞘内注射DNMT1-siRNA明显抑制大鼠神经病理性痛,其机制可能与促进脊髓SOCS1的表达,抑制p-ERK、p-CREB的表达有关。

Effects of DNMT1-siRNA on the pain behavior and the expression of SOCS1,p-ERK,p-CERB in CCI rats

Objective To investigate the effects of DNMT1 on neuropathic pain behavior and neuropathic pain modulation.Methods Thirty-two male SD rats, weighing 200-250 g, were randomly assigned into 4 groups (n =8 each):sham operation group (group S),chronic constrictive injury group (group CCI),CCI+ DNMT1-siRNA group (group CDS),CCI+ control-siRNA group (group CCS).Group CDS were intrathcally injected of DNMT1-siRNA (2 μg/10 μl),and group CCS were intrathcally injected of control-siRNA 7,8,9 days after operation.Mechanical withdrawal threshold (MWT)and thermal withdrawal latency (TWL)were measured before operation and on day 3,5,7,9,12,14 after operation.The rats were then sacrificed and L4-L6 segments of the spinal cord were removed for determination of SOCS1,p-ERK,p-CREB expression using Western blot on day 14.Results Compared with group S,MWT and TWL in group CCI and CCS were significantly decreased on day 3,5,7,9,12,14 after operation (P <0.05).Compared with group CCS,MWT and TWL in group CDS were significantly increased on day 9,12,14 after operation (P < 0.05 ). Compared with group S and CDS,SOCS1 was significantly downregulated,p-ERK and p-CREB were significantly upregulated in group CCI and CCS (P <0.05 ).Conclusion Intrathcal injection of DN-MT1-siRNA significantly relieves neuropathic pain by upregulating SOCS1,downregulating p-ERK and p-CREB in rats spinal cords.