二甲双胍缓解小鼠放射性皮炎引起的病理性疼痛:基于抑制p38 MAPK/NF-κB信号通路

Metformin alleviates pathologic pain in mice with radiation dermatitis by inhibiting p38MAPK/NF-κB signaling pathway

目的探讨二甲双胍(Met)对放射性皮炎病理性疼痛的治疗作用及其可能机制。方法将32只SPF级雄性ICR小鼠随机分为4组,即正常对照组(Control组)、放射性皮炎模型组(Model组)、二甲双胍干预组(Met组)及阳性药物加巴喷丁组(GBP组),8只/组。小鼠模型制备成功后,Met组小鼠采用腹腔注射方式给药,每次剂量为200 mg/(kg·d),连续给药16 d,GBP组加巴喷丁灌胃[100 mg/(kg·d)],连续灌胃16 d,Control组及Model组小鼠腹腔内注射与二甲双胍组等体积生理盐水。末次给药后评估各组小鼠放射性皮炎分级情况;分别于建模前及建模后第1、4、8、12、16天观察并记录各组小鼠建模侧(右侧)后足机械缩足反射阈值(MWT)和热缩足反射潜伏期(TWL);Westernblot检测脊髓L_(4)~L_(6)节段p38丝裂原活化蛋白激酶(p38MAPK)、核转录因子-κB p65(NF-κB p65)、磷酸化(p)-p38MAPK、磷酸化(p)-NF-κB p65蛋白表达。ELISA检测脊髓组织中白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)水平。结果与Control组相比,Model组、Met组及GBP组小鼠右后足表现出明显的放射性皮炎症状(P<0.05);与Model组及GBP组相比,Met组放射性皮炎症状减轻(P<0.05)。与Control组相比,Model组小鼠MWT和TWL降低(P<0.05);与Model组比较,Met组及GBP组MWT和TWL明显提高(P<0.05)。与Model组相比,Met组小鼠脊髓组织中p-p38MAPK及p-NF-κB p65蛋白表达降低(P<0.05),其炎症因子IL-1β、IL-6和TNF-α水平也明显降低(P<0.05)。结论二甲双胍可缓解放射性皮炎小鼠的病理性疼痛症状,且该作用可能是通过抑制p38MAPK/NF-κB信号通路的活化实现的。

Objective To observe the therapeutic effect of metformin on pathological pain in mice with radiation dermatitis and explore the underlying mechanism.Methods Thirty-two male adult ICR mice were randomized into normal control group,radiation dermatitis model group,metformin treatment(200 mg/kg)group and gabapentin(100 mg/kg)group(n=8).In the latter two groups,metformin treatment was administered after modeling via intraperitoneal injection and gabapentin by gavage on a daily basis for 16 days;the mice in the control group and model group received intraperitoneal injection of normal saline.After the last administration,radiation dermatitis was graded in each group.Mechanical withdraw threshold(MWT)and thermal withdrawal latency(TWL)of the mice were tested one day before and at 1,4,8,12 and 16 days after modeling.Western blotting was used to measure the protein expression levels of p38MAPK,p-p38MAPK,NF-κB p65 and p-NF-κB p65 in the L_(4)-L_(6) spinal cord,and the concentrations of IL-1β,IL-6 and TNF-αin the spinal cord tissue were determined with ELISA.Results Compared with those in the control group,the mice in the other 3 groups showed obvious symptoms of radiation dermatitis after modeling(P<0.05),which were significantly alleviated by treatment with metformin(P<0.05).The mice in the model group exhibited significant decreases in MWT and TWL(P<0.05),which were improved by treatment with metformin and gabapentin(P<0.05).Compared with those in the model group,the levels of p-p38MAPK,p-NF-κB p65,IL-1β,IL-6 and TNF-αin the spinal cord were significantly decreased in the mice after metformin treatment(P<0.05).Conclusion Metformin can significantly ameliorate pathological pain symptoms in mice with radiation dermatitis possibly by inhibiting the activation of p38MAPK/NF-κB signaling pathway.