系统性尖端赛多孢子菌感染小鼠IL-12表达的研究

Study on the expression of interleukin-12 in experimental murine systemic Scedosporium apiospermum infection

建立小鼠系统性尖端赛多孢子菌感染模型,用酶联免疫吸附试验(ELISA)及逆转录-聚合酶链反应(RT-PCR)分别检测脾内IL-12蛋白质及mRNA水平,用平皿系列稀释法检测肾内菌落形成单位(CFU),并记录平均生存时间(MST)。结果,脾内IL-12蛋白质含量:致死量组均低于正常组;亚致死量组均高于正常组,且第7天显著高于第3天;地塞米松免疫抑制组均高于正常组。此外,免疫抑制组均低于相应时间亚致死量组。脾中IL-12mRNA表达水平与蛋白质水平基本一致。致死量组及免疫抑制组肾内均有大量菌生长,亚致死量组肾内菌量少。致死量感染组平均生存时间为13.6天,免疫抑制组为14.2天,对照组和亚致死量组均超过45天。结果示健康鼠大量菌感染及免疫抑制鼠小量菌感染均可引起致死性感染,而IL-12在小鼠系统性尖端赛多孢子菌感染中可能具有保护作用。

Murine systemic Scedosporium apiospermum infection models were established and in these models,two site ELISA and RT PCR were applied to detect the level of IL 12 protein and mRNA expression in spleens respectively,clone forming units (CFU) of infected kidneys were determined with the plating dilution method, and mean survival time(MST) of the mice was also recorded. The results showed that IL 12 protein levels of the lethal infection group were lower than those of the intact controls. IL 12 protein levels of sublethal infection groups were higher than those of intact controls.IL 12 protein levels of dexamethasone induced immunosuppressed groups were lower than those of the intact controls.However, the levels of immunosuppressed groups were significantly lower than those of sublethal infection groups at the same days post infected(3 days and 7 days). The tendency of IL 12 mRNA expression was similar with that of IL 12 protein. As for fungal loads in kidneys , there were a large amount of fungi in kidneys of lethal infection group and immunosuppressed group while there were just a few fungi found in kidneys of sublethal infection group . The MST was 13.6 days for lethal infection group and 14.2 days for immunosuppression group, while that was beyond 45 days for both normal controls and sublethal infection group.It suggested that both the intact mice inoculated with large amount of fungi and the immunosuppressed mice inoculated with small amount of fungi led to lethal infection, while IL 12 might play a protective role in the murine systemic Scedosporium apiospermum infection .