不同毒力钩端螺旋体引起的细胞因子表达的差异

目的通过比较不同毒力钩端螺旋体引起豚鼠细胞因子表达的差异,探讨钩端螺旋体病的炎症反应及其发病机制。方法豚鼠腹腔内分别注射致病性钩端螺旋体赖型有毒株Lai株,赖型无毒株IPAV株,以及非致病性钩端螺旋体Patoc型Patoc1株,观察豚鼠各脏器的病理改变;EnVision二步法检测钩端螺旋体在各脏器中的分布;应用Real-ti me RT-PCR法检测豚鼠血液中细胞因子IFN-γ、TNF-α、IL-12、MCP-1mRNA的表达。结果钩端螺旋体IPAV株和Patoc1株不能引起豚鼠组织病变,但是在感染早期引起细胞因子的高表达;而Lai株可以引起典型的钩端螺旋体病病变,但是在感染早期引起细胞因子较低表达。结论致病性钩端螺旋体赖型毒力株Lai株引起的细胞因子的表达明显低于非致病钩端螺旋体Patoc型Pa-toc1株和赖型无毒株IPAV株,可能与钩端螺旋体病炎症反应轻微有关,有利于钩端螺旋体逃避宿主的免疫反应,在体内繁殖扩散。

The difference of cytokine responses induced by leptospira strains with different Virulence

To investigate the cytokine responses induced by different Leptospira strains,guinea pigs were intraperitoneally infected with the virulent Leptospira interrogans serovar Lai type strain Lai,the avirulent L.interrogans serovar Lai type strain IPAV,and the nonpathogenic L.biflexa serovar Patoc type strain Patoc 1 respectively.Histological changes and leptospiral antigen were detected by HE and EnVision staining,and the mRNA levels of cytokines in the blood of guinea pigs were quantified by real-time RT-PCR.The typical pathological changes of leptospirosis were observed in the strain Lai-inoculated guinea pigs.Although there were no apparent pathological lesions in the guinea pigs infected by the avirulent strain IPAV and the strain Patoc 1,the cytokine levels of IFN-γ、TNF-α、IL-12、MCP-1 were significantly higher than that in the guinea pigs infected by the strain Lai.Thus,the nonpathogenic stain Patoc 1 and the avirulent strain IPAV can induce a more rapid and robust host response,and the virulent strain Lai induces low levels of cytokines which may be correlated with the mild inflammatory responses of leptospirosis and escape of the host immune response.