地塞米松增强烟曲霉孢子侵袭力的研究

Dexamethasone′s enhancement of invasiveness of spores by Aspergillus fumigatus

目的探讨地塞米松预处理A549细胞后对孢子侵袭力的影响;比较黏附和内化(细胞内)孢子之间的数量关系,为临床资料提供参考依据。方法选自2013年1月-6月由医院微生物室鉴定的19株临床菌株,在不同浓度地塞米松条件下建立烟曲霉菌孢子侵袭上皮细胞的体外模型,应用Graphpad Prsm对内化组与黏附组侵袭率进行χ2分析。结果不同浓度地塞米松预处理A549细胞4h后,各组烟曲霉孢子的侵袭力无明显差异,而预处理24h后,25mg/L地塞米松组孢子侵袭力(26.44±2.45)%高于5mg/L组(23.56±3.16)%、1mg/L组(19.81±3.63)%和0mg/L组(18.17±2.77)%,除0mg/L组和1mg/L组之间侵袭力无差异外,其余任意两组侵袭力差异均有统计学意义(P<0.05);27.2%黏附孔子进入细胞(P<0.05)。结论烟曲霉孢子的侵袭力与地塞米松作用的时间和浓度成正相关,侵袭性曲霉病主要由黏附孢子引起。

OBJECTIVE To explore the impact of the dexamethasone on the invasiveness of conidia after pretreat- ment of A549 cells and compare the quantitative relation between adherent and internal conidia in order to provide reference frame for clinical data. METHODS A total of 19 clinical isolates were identified by the clinical microbiolo- gy lab in the hospital from Jan to Jun 2013, then the in vitro model of invasiveness of epithelial cells of Aspergillus fumigatus spores was established under different concentrations of dexamethasone, and the variance analysis of the invasion rate was performed for the internalization group and the adhesion group with the use of Graphpad Prism. RESULTS After the A549 cells pretreatment was pretreated for 4 h by dexamethasone with different concentrations, no significant difference of A. fumigatus spores invasiveness between groups was detected. While after the pretreatment for 24 h, spore invasion force in 25 mg/L dexamethasone group （26.44 ± 2.45）% was higher than that in 5 mg/L group （23. 56±3. 16）% , 1 mg / L group （19. 81±3.63）%, and 0 mg/L group （18.17±2.77%）. Except that the difference of invasion force between 0 mg/L group and lmg/L group was not significant, the difference of the invasion force of any the rest of two groups was statistically significant （P〈 0.05） ± 27.2 % of the adhered spores have invaded into the cells （P〈0.05 %）. CONCLUSION The invasion force of A. fumigatus spores is positively correlated with the using time and concentration of dexamethasone. The inva- sive aspergillosis is mainly caused by the adherent spores.