抗C3a多克隆抗体对实验性结肠炎小鼠的疗效初探

目的评价抗补体C3a抗体治疗TNBS诱导的实验性肠炎的可行性。方法 70只6～8周龄的雄性BALB/c小鼠随机分为对照组、模型组及抗C3a抗体预防和治疗、泼尼松龙治疗共5组,对照组直肠灌注50%乙醇,模型组给予TNBS(2.5毫克/只)。抗C3a抗体预防组分别在建模型前2天,建模后0、2和5天腹腔注射抗体[50微克/(次.只)],抗C3a抗体治疗组则在建模后2、5天给予抗体,剂量与前相同。泼尼松龙治疗组在在建模后2、5天给予药物[1毫克/(千克.次)]。每日测体重,观察腹泻、血便等性状。分别于建模后2、24h检测血浆和结肠中的C3a水平,建模后4天时检测结肠中肿瘤坏死因子-α(TNF-α)和髓过氧化氢酶(MPO)的表达水平,观察期结束后,分离结肠病灶,观察组织学病理变化。结果 TNBS肠炎建模后2h和24h血浆和结肠中补体C3a含量明显升高,尤以结肠更为显著。与模型组相比,抗C3a抗体预防和治疗组小鼠体重下降得到有效遏制,结肠病变程度出现明显减轻。抗体治疗组小鼠结肠中TNF-α和MPO的含量显著降低。这些指标的变化与泼尼松龙治疗组相当。结论上述结果证实了抗C3a抗体治疗炎症性肠病的可行性,提示靶向补体C3a的单克隆抗体可能是临床治疗炎症性肠病的潜在药物。

Evaluation of Therapeutic Effects of Polyclonal Anti-C3a Antibody Treatment in TNBS-induced Experimental Colitis in Mice and Involving Mechanisms

Objective To investigate the efficacy of anti-C3a antibody treatment in trinitrobenzene sulfonic acid(TNBS)-induced experimental colitis.Methods 6-8 weeks male BALB/c mice(n=70) were randomized into control,TNBS,TNBS+anti-C3a pretreatment,TNBS+anti-C3a posttreatment,TNBS+prednisolone posttreatment groups.Mice were treated with 50% ethanol or TNBS(2.5mg/mouse) intrarectally.Anti-C3a antibody was injected(50μg/mouse) intraperitoneally on-2,0,2,5 day after TNBS instillation.To evaluate the therapeutic effects,antibody was given on 2 and 5 day following TNBS treatment.For positive controls,prednisolone was given(1mg/kg) intraperitoneally at the same intervals.Several parameters including body weight,diarrhea and bloody stool were monitored daily.C3a levels in plasma and colons were detected at 2 and 24h after TNBS instillation.Colonic TNF-α and MPO were examined on day 4 after TNBS.Furthermore,colon tissues were dissected,processed routinely and stained with hematoxylin and eosin.Results C3a levels in plasma and colons were elevated dramatically at 2 and 24h after TNBS instillation.This effect was more pronounced in colons.Compared with TNBS-instilled group,anti-C3a-treated mice exhibited reduced weight loss and attenuated intestinal damage.Anti-C3a treatment decreased the production of colonic TNF-α and MPO,which was comparable to prednisolone treatment.Conclusion These data testify the feasibility of anti-C3a treatment in inflammatory bowel disease,indicating the therapeutic potentials of monoclonal anti-C3a antibody in clinic.