通过观察miR-125b-5p对分枝杆菌在宿主细胞和小鼠体内存活情况的影响，探究其在抗结核免疫过程中的作用。采用不同培养基对分枝杆菌进行培养并计数；以1640培养基加10%胎牛血清培养所有实验用细胞。将终浓度50 nmol/L的miR-125b-5p 模拟物、miR-125b-5p 抑制剂及磷酸盐缓冲液(PBS)对照加入细胞后，在不同时间点收集细胞。用分枝杆菌分别感染宿主细胞(A549、THP-1和RAW264.7)以及C57BL/6小鼠。采用定量聚合酶链反应检测miR-125b-5p的表达量。结果miR-125b-5p在分枝杆菌感染的多种宿主细胞及小鼠中都显著上调表达，其中小鼠肺部的表达量提高了约15倍。分别转染模拟物和抑制剂后，再用分枝杆菌感染细胞，结果发现miR-125b-5p可促进分枝杆菌在宿主细胞内的生长。当miR-125b-5p抑制剂注射到卡介苗(BCG)感染的小鼠体内时，小鼠体内的细菌载量显著降低(P<0.05)。本研究证明miR-125b-5p可调控分枝杆菌在宿主细胞及小鼠体内的生长，在抗结核免疫过程中发挥了重要作用。进一步对其作用机制的深入研究将为临床结核病的治疗提供理论指导。

MicroRNAs (miRNAs) play an important role in the regulation of the immune system. To demonstrate the role of miR-125b-5p in anti-TB immunity, we have infected host target lung alveolar A549, human macrophage THP-1, mice macrophage RAW264.7 and C57BL/6 mice, respectively. The q-PCR results demonstrated that miR-125b-5p is highly expressed in the tested conditions. The expression of miR-125b-5p in BCG infected mice lung was about 15 times of that in the control mice. The results verified that miR-125b-5p regulated mycobacteria growth in A549, THP-1 and RAW264.7 cells, respectively. Moreover, administration of miR-125b-5p inhibitors in BCG infected mice significantly reduced bacteria burden in lung. Thus, we concluded that miR-125b-5p may play a critical role on mycobacteria proliferation in vivo. The results provide useful information for our understanding of host immune defense and potential therapeutic interventions against this disease.