经皮神经电刺激对痛觉敏化诱发模型大鼠背根神经节IL-33/ST2信号通路的影响

Effects of transcutaneous electrical nerve stimulation on IL-33/ST2 signaling pathway in the dorsal root ganglion of rats modeling hyperalgesia

目的探究经皮神经电刺激(TENS)对痛觉敏化诱发(HP)模型大鼠背根神经节(DRG)白细胞介素-33(IL-33)/受体生长刺激表达基因2蛋白(ST2)信号通路的影响。方法本研究分为2个实验进行。实验1,将30只SD大鼠按照随机数字表法分为空白组、假HP组、HP组、抗体组、抑制剂组,每组6只;除空白组和假HP组外,其余组大鼠在左后足足底皮下注射角叉菜胶(Car)和前列腺素E2(PGE2),建立HP模型;抗体组和抑制剂组大鼠,分别给予鞘内注射抗ST2抗体和肿瘤坏死因子α(TNF-α)特异性抑制剂;以Car注射为基准点(0 h),在4 h、24 h、48 h、72 h,以及7 d、7 d 1 h、7 d 4 h、7 d 24 h,对大鼠行机械痛阈检测;Car注射后7 d 24 h,采用免疫荧光技术和Western blot法检测各组大鼠IL-33、ST2和TNF-α的表达情况。实验2,将42只SD大鼠按照随机数字表法分为假HP组、HP组、TENSⅠ组、TENSⅡ组、TENSⅠ抑制剂组、TENSⅡ抑制剂组、假TENS组,每组6只;所有大鼠均建立HP模型,造模方法和假HP组处理方法同实验1;TENSⅠ组、TENSⅡ组、TENSⅠ抑制剂组、TENSⅡ抑制剂组均给予TENS干预,TENSⅠ抑制剂组和TENSⅡ抑制剂组大鼠均给予鞘内注射TNF-α特异性抑制剂;以Car注射为基准点(0 h),在4 h、24 h、48 h、72 h,以及7 d、7 d 1 h、7 d 4 h、7 d 24 h,对大鼠行机械痛阈检测;Car注射后7 d 24 h,采用Western blot法检测各组大鼠IL-33、ST2和TNF-α的蛋白表达水平。结果实验1,Car注射后4 h、24 h、48 h、72 h,与空白组和假HP组同时间点比较,HP组、抗体组、抑制剂组大鼠的机械痛阈显著降低(P<0.05);Car注射后7 d 1 h,假HP组、抗体组、抑制剂组大鼠的机械痛阈较HP组显著升高(P<0.05),IL-33、ST2和TNF-α表达较HP组显著降低(P<0.05)。实验2,Car注射后4 h、24 h、48 h、72 h,与假HP组比较,其余组大鼠的机械痛阈显著降低(P<0.05);Car注射后7 d 1 h,经TNES干预大鼠的机械痛阈较假TENS组显著升高(P<0.05);TENSⅡ组大鼠的机械痛阈较TENSⅠ组显著降低(P<0.05),IL-33、ST2和TNF-α表达显著升高(P<0.05);与TENSⅠ组和TENSⅡ组比较,TENS I抑制剂组和TENSⅡ抑制剂组大鼠的机械痛阈显著升高(P<0.05),IL-33、ST2和TNF-α表达显著降低(P<0.05)。结论TENS可能通过下调TNF-α水平影响IL-33/ST2信号表达,进而逆转疼痛转化。TENS联合抗TNF-α治疗较单独的TENS治疗对HP有更好的逆转作用。

Objective To explore the effect of transcutaneous electrical nerve stimulation(TENS)on interleukin-33(IL-33)/growth stimulation expressed gene 2(ST2)signaling pathway in the dorsal root ganglia(DRGs)of rats modeling hyperalgesia(HP).Methods This study consisted of two experiments.In the first,30 Sprague-Dawley(SD)rats were randomly divided into a blank group,a Sham-HP group,an HP group,an antibody group and an inhibitor group,each of 6.HP was induced in all except the rats of the blank and Sham-HP groups by injecting carrageenan(Car)and prostaglandin E2 subcutaneously at the bottom of the left hind feet.The antibody and inhibitor groups were then given intrathecal injections of anti-ST2 antibody and a tumor necrosis factorα(TNF-α)-specific inhibitor,respectively.In the second experiment,42 SD rats were randomly divided into a Sham-HP group,an HP group,a TENSⅠgroup,a TENS Ⅱ group,a TENS Ⅰ inhibitor group,a TENS Ⅱ inhibitor group,and a Sham-TENS group,each of 6.All of the groups had HP induced as in experiment one.All of the rats except those in the Sham-HP,HP and Sham-TENS groups were then given TENS,and the TENS Ⅰ and Ⅱ inhibitor groups were offered intrathecal injection of TNF-α-specific inhibitors.Mechanical pain thresholds(MPTs)were documented 4h,24h,48h,72h,6d,7d 4h,7d 1h,and 7d after the Car injections.Western blotting was used to measure the protein expressions of IL-33,ST2 and TNF-α6d after the Car injection in both experiments.Results In experiment one,the average MPTs of the HP,antibody and inhibitor groups had decreased significantly 4 hours after the Car injection compared with the blank and Sham-HP groups.However,7d 1h after the Car injection the value had increased significantly in the Sham-HP,antibody and inhibitor groups compared with the HP group,while the expressions of IL-33,ST2 and TNF-αhad decreased significantly.In experiment two,by 4 hours after the Car injection,the average MPT of all the other groups had decreased significantly compared with the Sham-HP group.Moreover,by 7d 1h after the Car injection,the average MPTs of the groups receiving TENS had increased significantly,with significantly lower MPT in the TENSⅡgroup than in groupⅠ,on average.There was also significantly higher expression of IL-33,ST2 and TNF-αin group II.Compared with the TENSⅠandⅡgroups,the average MPT was significantly higher in the TENS Ⅰ andⅡinhibitor groups,but IL-33,ST2 and TNF-αexpression was lower.Conclusions TENS can inhibit TNF-αexpression,which influences the signals of the DRG IL-33/ST2 signaling pathway to reverse hyperalgesia.TENS combined with anti-TNF-αtreatment is superior to TENS alone in treating hyperalgesia.