IL-17单克隆抗体对病毒性心肌炎小鼠的保护作用及其机制

Protective effect and mechanism of IL-17 monoclonal antibody on mice with viral myocarditis

目的探讨IL-17单克隆抗体(mAb)对病毒性心肌炎(VMC)小鼠的保护作用及可能机制。方法 90只BALB/c小鼠随机分为正常对照组(n=15)、模型组(n=15)、同型对照组(n=25)及IL-17 mAb组(n=25)。模型组、同型对照组、IL-17mAb组小鼠腹腔接种0.1 mL内含柯萨奇病毒B3(CVB3)的Eagle液建立VMC模型,对照组仅注射Eagle液。接种后第3、5天,同型对照组腹腔注射100μg非特异性IgG,IL-17抗体组腹腔注射100μg IL-17 mAb。第7天,每组处死5只小鼠,取心脏,采用Reed-Muench法测定病毒滴度,实时荧光定量PCR检测CVB3 mRNA拷贝数。第14天称体质量后处死全部小鼠,比较各组死亡率;分离血清,ELISA测定血清心肌肌钙蛋白I(cTnI)浓度;称心脏质量(HM),计算心脏指数(HM/BM);HE染色计算心肌病理积分,Western blot法测定心脏核因子-κB(NF-κB)p65表达,ELISA检测心脏IL-6、TNF-α含量。结果模型组心脏指数、血清cTnI浓度、NF-κB p65表达水平及心脏IL-6、TNF-α含量高于对照组(P<0.01)。IL-17 mAb组死亡率、心脏指数、血清cTnI浓度、心肌病理积分、病毒滴度、CVB3 mRNA拷贝数、NF-κB p65表达水平及心肌IL-6、TNF-α含量较模型组及同型对照组减少(P<0.05或P<0.01)。同型对照组上述指标与模型组比较,无显著性差异(P>0.05)。结论 IL-17 mAb能够减轻VMC小鼠心肌损伤,其机制可能与抑制病毒复制及NF-κB激活有关。

Objective To explore the protective effects of interleukin-17 monoclonal antibody （IL-17 mAb） on viral myocarditis （VMC） mice and its possible molecular mechanisms. Methods Ninety BALB/c mice were randomly divided into 4 groups： normal control group （ n = 15）, model group （ n = 25）, isotype control group （ n = 25 ） .and IL-17 mAb group （ n = 25）. Mice in model, isotype control and IL-17 mAb groups were inoculated with 0. 1 mL Eagle＇s solution containing Coxsackievirus B3 （CVB3） intraperitoneally; and those in normal control group were treated with 0.1 mL Eagle＇s solution without CVB3. On the day 3 and 5 after inoculation, mice in isotype control and IL-17 mAb groups received intragastric administration of 100 pg non-specific IgG antibody and IL-17 mAb, respectively. On day 7 postinoculation, 5 mice were killed in each group, and the hearts were removed. Virus titer was detected using Reed-Muench method, and CVB3 mRNA copy number was measured by real-time quantitative PCR. All mice were killed on day 14 after weighing body mass （BM）. The mortality was compared among groups. Serum was separated and serum cardiac troponin I （cTnl） concentration was detected using ELISA. The heart was removed and weighed to calculate heart index （HM/BM）. Histological sections of heart were stained with hematoxylin-eosin and myocardial histopathologic scores were counted under optical microscope. The expression of nuclear factor-KB （NF-KB） [065 was examined by Western blotting. Myocardial interleukin-6 （IL-6） and tumor necrosis factor-a （TNF-a） levels were detected by ELISA. Results The HM/BM, serum cTnl concentration, NF-KB p65 expression level and myocardial IL-6 and TNF-a contents in model group were higher than those in normal control group （P〈0.01）. In comparison with model and isotype control groups, mortality, HM/BM, serum cTnl concentration, myocardial histopathologic scores, virus titer, CVB3 mRNA copy number, NF-KB p65 expression level, and myocardial IL-6 and TNF-a contents in IL-17 mAb group were significantly reduced （P〈0. 05 or 0. 01 ）. There was no difference in the above indicators between isotype control group and model group（P〉0.05）. Conclusion IL-17 mAb can improve myocardial injury in VMC mice, and the mechanisms are associated with the inhibition of viral replication and NF-KB activation.