热灭活隐球菌对小鼠隐球菌脑炎的作用及其机制

Effect of heat-inactivated Cryptopcoccus neoformans on experimental mice meningoencephalitis and its mechnism

目的:研究脑内接种热灭活的隐球菌(heat—inactived Cryptococcus neoformans,H-CN)在中枢神经系统隐球菌感染中的作用及对小鼠脑和脾IL-2、IL-6基因表达的影响。方法:实验动物随机分为实验组(先给予两次脑内接种H—CN)和对照组(先给予两次脑内接种生理盐水),然后分别取两组中部分小鼠的脑和脾用RT—PCR方法检测IL-6 mRNA和IL-2 mRNA基因表达,同时给予两组剩余小鼠脑内接种致死量的隐球菌,观察小鼠脑组织病理改变。结果:小鼠脑组织总RNA以IL-6和IL-2引物进行RT—PCR,实验组IL-6表达阳性,IL-2表达阴性,对照组IL-6、IL-2均表达阴性。小鼠脾组织总RNA以IL-6和IL-2两种引物进行RT—PCR,两组IL-6、IL-2均表达阴性。实验组小鼠脑组织病理与对照组相比可见侧脑室的隐球菌周围有大量的炎性细胞浸润。结论:脑内接种H—CN可引起中枢神经系统特异性免疫反应,中枢神经系统抗隐球菌机制很可能与H—CN引起局部细胞因子IL-6的分泌有关。

Objective:To investigate the effect of heat inactivated Cryptpcoccus neoformans(H-CN) on experimental mice meningoencephalitis and on IL-6 mRNA and IL-2 mRNA expression in mice brains and spleens. Methods:Mice were divided into H-CN-treated group and control group at random. Two group mice brains and spleens were collected to obtain total RNA. IL-6 mRNA and IL-2 mRNA were detected by RT-PCR method. After Local challenging with lethal dose of C. neofar-mans,the histopathologic changes of the rest mice in 2 groups were observed. Results:Positive electrophoretic results of RT-PCR products of brains by IL-6 primer and negative by IL-2 primer were observed in H-CN-treated group,negative by IL-6 and IL-2 primers were observed in control group. Negative electrophoretic results of RT-PCR products of spleens by TL-6 and IL-2 primers were observed in 2 groups. Compared with control group,histopathologic changes of massive local inflmmatory response were seen in H-CN-treated group. Conclusion: It suggests intracerebral inoculation of H-CN can establish specific im mune responses .the anticrptococcal mechanism of central nervous system probably involves H-CN elicitation of IL-6.