HSV-1上调白细胞介素-18mRNA在小鼠角膜组织中表达的研究

Herpes simplex virus type 1-mediated up-regulation of interleukin-18 mRNA expression in murine cornea

目的研究单纯疱疹病毒Ⅰ型(HSV-1)感染小鼠眼球后,白细胞介素-18(IL-18)在角膜组织中的表达及IL-18的表达与单纯疱疹性角膜基质炎之间的关系.方法用106PFU的HSV-1感染BALB/c鼠的角膜后,在裂隙灯显微镜下观察角膜的临床变化,组织学检查角膜的病理改变;用RT-PCR和ELISA法检测IL-18在角膜组织中的表达水平.结果HSV-1引起的角膜基质炎在病毒感染后的第10 d明显可见,在病毒感染后的第14～21 d达到高峰.RT-PCR检测的数据显示:HSV-1感染的早期即可诱导IL-18 mRNA在角膜组织中的表达,并且表达持续存在;IL-18 mRNA的表达高峰时间(3～21 d)位于临床疾病出现之前和临床疾病发展的过程中.ELISA检测角膜提取物中的IL-18蛋白显示了相似的结果.结论HSV-1上调IL-18在小鼠角膜组织中的表达;IL-18的表达与角膜基质炎的发生和发展密切相关;IL-18诱导Th1细胞介导的对单纯疱疹病毒特异性的免疫反应,导致单纯疱疹性角膜基质炎.

Objective To investigate the expression of interleukin-18 （IL-18） in the cornea of mice following ocular herpes simplex virus type ｜ （ HSV-1） infection and its relationship with herpetic stromal keratitis. Methods Right corneas 70 BALB/c mice were infected with 106 PFU of HSV-1 McKrae strain,and uhraviolet-inactivited HSV was used in 60 mice and 5μl PBS for 20 control mice. The clinical evaluation of infected eyes were taken under the slit-lamp microscope,and the histological changes of corneas was analyzed under the light microscope. The expression of IL-18 in cornea was detected following HSV-1 corneal inoculation by reverse transcription polymerase chain reaction （RT-PCR） and enzyme-linked immunosorbant assay （ ELISA）. Results HSV-induced corneal stromal opacification became evident at day 10 and was most severe at 14 to 21 days after viral infection in mice. Expression of IL-18 mRNA in the cornea was seen in the early infection period and reached the highest level in 3-21 post-inoculation days after infection by HSV and only slight expression in the 1 st and 3rd day on the cornea infected by inactivated HSV. HSV infection also induced corneal edema and neutrophilic granulocyte and lymphocyte infiltration in the 28th day, however, no responses mentioned above were seen on the infected cornea by ultraviolet-inactivated HSV. ELISA assay demonstrated that the expression of IL-18 protein was similar with the result of its message RNA. Conclusion HSV-1 mediates up-regulation of IL-18 expression in murine cornea. Expression level of IL-I 8 in the cornea correlates with the occurrence and development of HSK. IL-18 induction may act as a triggering event that biases HSV-specific immunity to a type 1 T cell response to the pathogenesis of HSK.