Caspase-3基因沉默对肺炎链球菌感染的肺泡上皮细胞凋亡的影响

目的:通过siRNA抑制caspase-3基因的表达探讨肺炎链球菌对肺泡上皮细胞凋亡的影响及凋亡基因caspase-3对凋亡的调节作用,寻找治疗肺炎链球菌肺炎的新方法。方法:体外培养肺泡上皮细胞A549,用肺炎链球菌R6作用于A549细胞,使用siRNA技术抑制caspase-3表达,RT-PCT法检测caspase-3转录强度,化学荧光测定法检测caspase-3蛋白含量,ELISA法检测细胞上清中IL-6和IL-10浓度,TUNEL法检测细胞凋亡。结果:肺炎链球菌能诱导A549细胞凋亡、导致caspase-3的表达和IL-6的浓度升高、IL-10的浓度降低;使用siRNA抑制caspase-3表达后,caspase-3的表达降低,A549细胞的凋亡率降低,而IL-6和IL-10的浓度并无明显变化。结论:Caspase-3在肺炎链球菌引起的肺泡上皮细胞的凋亡中占据了重要的地位;运用RNA干扰技术抑制caspase-3的表达能降低肺泡上皮细胞的凋亡率,这可能对肺炎链球菌肺炎的治疗有积极意义。

Caspase-3 gene silencing attenuates apoptosis in alveolar epithelial cells after Streptococcus pneumoniae infection

AIM: To investigate the influence of Streptococcus pneumoniae on the apoptosis of alveolar epithelial cell and the modulation of caspases-3 on apoptosis. METHODS: A study was undertaken to determine whether Streptococcus pneumoniae infection induced the apoptosis of A549 and facilitated the expression of pro-inflammative cytokine. After inhibited by siRNA, the expression of caspase-3 and apoptosis grade in A549 were determined. RESULTS: Streptococcus pneumoniae contributed to alveolar epithelial cell apoptosis in a time-dependent manner. Streptococcus pneumoniae facilitated the expression of caspase-3 and IL-6 in A549, while depressed IL-10 concentration in culture medium. SiRNA directly decreased the expression of caspase-3 to rescue A549 from apoptosis but not affected IL-6 and IL-10 concentration. CONCLUSION: caspase-3 gene silencing rescues epithelial cells from apoptosis initiated by Streptococcus pneumoniae infection.