Sigma-1受体在神经病理性疼痛大鼠内质网应激中的作用

The role of sigma-1 receptor in endoplasmic reticulum stress in neuropathic pain rats

目的 探讨sigma-1受体(sig-1R)对神经病理性疼痛(NP)大鼠内质网应激的作用。方法 将鞘内置管成功的SPF级雄性SD大鼠24只按随机数字表法分为假手术组(S组)、NP模型组(C组)、sig-1R抑制剂BD1047干预组(B组),每组8只。C组和B组采用坐骨神经慢性挤压性损伤法建立NP模型。术后第4、5、6天,S组和C组鞘内注射生理盐水20μL,B组鞘内注射BD1047(120μmol/L)20μL,1次/d。于术前1 d及术后第1、3、5、7天检测术侧足机械缩足反应阈(MWT)。采用Westen blot和免疫荧光染色法检测背根神经元(DRG)sig-1R、免疫球蛋白重链结合蛋白(BIP)、转录活化因子4(ATF4)、C/EBP同源蛋白(CHOP)的表达情况;采用HE染色法观察DRG形态大小及病理改变;采用透射电镜观察DRG内质网改变。结果 与S组比较,C组大鼠术后各时间点术侧足MWT明显下降,DRG病理损伤和内质网破坏明显加重,sig-1R、BIP、ATF4、CHOP表达均上调(P<0.05);与C组比较,B组大鼠术后第5、7天MWT升高,DRG病理损伤和内质网破坏减轻,sig-1R、BIP、ATF4、CHOP表达均下调(P<0.05)。结论 sig-1R参与了大鼠神经病理性疼痛的过程,其机制可能与抑制DRG内质网应激有关。

Objective To investigate the role of sigma-1 receptor(sig-1R)in endoplasmic reticulum stress in neuropathic pain(NP)rats.Methods Twenty-four SPF male SD rats with successful sheath tube were divided into the sham operation group(group S),the neuropathic pain model group(group C)and the BD1047 intervention group(group B)according to random number table,with 8 rats in each group.Chronic crush injury of sciatic nerve was used to establish NP model.On the 4th,5th and 6th day after operation,normal saline 20μL was injected intrathecally in the group S and the group C,and BD1047(120μmol/L)20μL was injected intrathecally in the group B once a day.The mechanical foot withdrawal response threshold(MWT)of the surgical side foot was measured on the first day before operation and on the first,3rd,5th and 7th day after operation.Western blot assay and immunofluorescence staining were used to detect the expression levels of sig-1R,glucose-regulated protein(BIP),activating transcription factor 4(ATF4)and C/EBP-homologous protein(CHOP)in dorsal root neurons(DRG).HE staining was used to observe the morphological size and pathological changes of DRG.Changes of endoplasmic reticulum in DRG were observed by scanning electron microscopy.Results Compared with the group S,intraoperative parapodum MWT was significantly decreased(P<0.05),and pathological injury and endoplasmic reticulum destruction of DRG were significantly aggravated.Expressions of sig-1R,BIP,ATF4 and CHOP were upregulated in the group C after CCI(P<0.05).Compared with the group C,the MWT was increased on the 5th and 7th day after CCI in the group B(P<0.05),and the expressions of sig-1R,BIP,ATF4 and CHOP were down-regulated(P<0.05).The pathological injury of DRG was improved.Conclusion sig-1R are involved in the neuropathic pain in rats,and the mechanism may be related to the inhibition of endoplasmic reticulum stress in dorsal root neurons.