雌激素依赖的外阴阴道假丝酵母菌病小鼠模型中NF-κB、IL-1β和COX-2 mRNA的表达及意义

Expression and Significance of NF-κB,IL-1β and COX-2 mRNA in the Murine Model of Estrogen-dependent Experimental Vulvovaginal Candidiasis

目的观察NF-κB、IL-1β和COX-2 mRNA在雌激素依赖的外阴阴道假丝酵母菌病(VVC)小鼠模型中的动态变化,探讨雌激素诱发VVC的可能机制。方法采用雌性昆明种小鼠,预先皮下注射雌激素使其处于假发情状态,然后接种5×106假丝酵母菌孢子构建VVC模型(EI组),并设置雌激素处理未感染组(E组)、未用雌激素处理感染组(I组)和空白对照组(C组)。动态观察小鼠阴道灌洗液真菌载量计数(CFU),于接种后的不同时间点摘取小鼠阴道组织。分别采用原位杂交、免疫组化和ELISA检测其COX-2 mRNA、NF-κB的表达及IL-1β水平。结果COX-2 mRNA在E组阴道组织的表达水平明显高于C组(P<0.01),EI组表达水平高于其它3组;接种后第4、7、14天EI组及I组IL-1β水平均高于C组(P<0.01),EI组在第4、7天高于I组(P<0.01);E组NF-κB的阳性表达率从第4天开始就明显高于C组(P<0.01),而EI组显著高于I组(P<0.01)。结论在雌激素依赖的VVC小鼠模型中,雌激素激活阴道组织中NF-κB信号通路,上调COX-2的表达,与感染形成有关;而形成感染后,IL-1β和NF-κB相互作用使COX-2强表达则与感染持续有关。

Objective To observe the dynamic changes of nuclear factor-xB, interlenkin-1βand cyclooxygenase-2 mRNA in the murine model of estrogen-dependent experimental vulvovaginal candidiasis （VVC） in order to investigate the possible role of estrogen in the pathogenesis of VVC. Methods Estrogen-dependent experimental murine model of C. albicans vaginal infection was established by injecting subcutaneously estradiol benzoate to sustain the state of pseudoestrus of mice and then inoculating intravaginally 5 × 10^6 stationary-phase C. albicans blastoconidia to mice （El group）, and other 3 groups were set up： estrogentreated but not infected （E group）; estrogen-untreated but infected （I group）; normal control （C group）. The dynamic change of colony-forming unit （CFU） of cervivovaginal lavage fluid was observed. Vaginal tissues at different time points after inoculation of C. albicans were obtained. In situ hybridization staining was used to detect the expression of COX-2 mRNA and the expression of NF-κB was examined by immuohistochemistry. ELISA was applied to determine the IL-1β levels. Results The constitutional high level of the COX-2 mRNA expression in the vaginal tissue of E group was significantly higher than in C group at 4th and 7th day （P〈0.01）, and absorbance （A） value in E1 group was higher than in the other 3 groups （P〈0.05）. There were higher IL-1β levels in vaginal tissues from 4th to 7th day postinoculation in E1 group and I group than in group C （P〈 0.01）. Furthermore, IL-1β in E1 group was markedly elevated at 4th and 7th day as compared with I group （P〈0.01）. Compared with C group, the expression of NF-κB in E group was increased obviously at 4th day （P〈0.01）, and there was significant difference between E1 group and I group at 4th and 7th day （P〈0, 01）, Conclusion In the murine model of estrogen-dependent experimental VVC, estrogen promotes the infection establishment by up-regulating the expression of COX-2 via activating NF-κB signaling pathway, and the high expression of COX-2 promoted by the interaction of IL-1β and NF-κB after infection formation is involved in the persistence of infection.