IL-12表达水平变化及其免疫活性对病毒性心肌炎的影响

The expression of IL-12 mRNA and the effects of rIL-12 on murine viral myocarditis

目的 探讨在小鼠急性病毒性心肌炎 (VM)发病过程中白细胞介素 12 (IL 12 )mRNA表达水平和蛋白浓度变化 ,及其免疫学活性对心肌炎的影响。方法 135只雄性BALB/c小鼠随机分为正常组 (n =2 5 )、心肌炎对照组 (n =5 0 )、rIL 12组 (n =40 )、IL 12抗体组 (n =2 0 ) ,后 3组经腹腔接种柯萨奇病毒 (CVB3m)诱发急性心肌炎 ,rIL 12组于病毒接种后 4h皮下注射重组IL 12 ,10ng/ 0 .1ml,心肌炎组注射等量PBS ,均连续用 5d(0～ 4d) ,抗体组于 0～ 1d经腹腔注射IL 12中和抗体 0 .1mg/ 0 .1ml,共 2次 ,分别于接种后 1、3、5、7d各组随机取若干只小鼠采血后处死 ,留取心脏、脾等标本。结果 小鼠感染CVB3m后 ,其心肌组织中IL 12mRNA的表达水平增高 ,同时体内IL 12、IFN γ的蛋白含量也增高 ;在投入rIL 12后 ,IFN γ的蛋白含量升高更明显 ,NK细胞活力增强 ,同时小鼠心肌组织中病毒滴度降低 ,心肌损害减轻 ,小鼠生存率提高 (分别为 6 6 %和 85 % ) ;而在IL 12抗体投入组结果则相反 ,且小鼠生存率降低 (5 0 % ) ,但与心肌炎组相比差异无显著性。结论 在VM早期小鼠体内rIL 12能减轻心肌损害 ,提高感染小鼠的存活率 ,起到保护性的作用。

Objectives To study the expression of interleukin-12 (IL-12) mRNA in murine viral myocarditis and the effects of rIL-12 on murine myocarditis induced by Coxsackie virus B (CVB 3). Methods BALB/c mice were intraperitoneally inoculated with CVB 3, thereafter rIL-12(10ng/0.1ml/day) was administered on day 0 to 4. Anti-IL-12 neutralizing antibody(0.1mg/0.1ml/day) was administered on day 0 to 1 respectively. Control group (CVB 3 infected) was used with same dose PBS. Mice were killed at day 1, 3, 5 and 7. The expression of IL-12 mRNA and protein concentration of IL-12, IFN-γ, NK cell activity, virus replication and myocardial damage were studied by RT-PCR, ELISA, LDH release assay, titer determine and histopathology technology respectively. Results The mRNA expression and protein concentration of IL-12 were increased after CVB 3 inoculation and NK activity elevated. In rIL-12 treated group, IFN-γ production and NK activity increased more significantly, meanwhile virus titer in myocardium was decreased, myocardial damage was mitigated and mice survival rate was markedly increased (66%, 85%, respectively). But in anti-IL-12 neutralizing antibody treated group, except NK cell activity and the production of IFN-γ was decreased than that of control group, there was no statistical difference of survival rate between the two groups(66%, 50% respectively). Conclusion IL-12 offers protection in the early phase of viral myocarditis of mouse. [