目的探讨不同毒力结核分枝杆菌对感染宿主巨噬细胞应激的调控作用。方法以结核分枝杆菌国际标准强毒株H37Rv菌株(简称H37Rv菌株)和卡介苗菌株(简称BCG)分别感染小鼠巨噬细胞RAW264.7,在感染1、6、12、24h后,分别采用化学比色法检测感染巨噬细胞超氧化物歧化酶(SOD)和一氧化氮合酶(NOS)的活性变化,并测定感染巨噬细胞的丙二醛(MDA)和一氧化氮(NO)含量变化。结果RAW264.7感染BCG后细胞内SOD、NOS活性和NO含量逐渐升高,感染24h分别为(32.82±0.54)U/ml、(12.16±0.29)U/ml和(116.42±3.23)μmol/L,与对照组比较差异有统计学意义(P〈0.05);MDA含量逐渐下降,感染24h时为(0.59±0.08)nmol/ml,与对照组比较差异有统计学意义(P〈0.05);RAW264.7感染H37Rv菌株后细胞内SOD、NOS和NO含量逐渐下降,感染24h分别为(15.90±0.20)U/ml、(2.32±0.11U/m1)和(13.74±1.01μmol/L),与对照组比较差异有统计学意义(P〈0.05):MDA含量逐渐增加,感染24h时为(5.21±0.39)nmol/ml,与对照组比较差异有统计学意义(P〈0.05)。结论低毒力和高毒力结核分枝杆菌分别对感染宿主巨噬细胞的应激发挥诱导和抑制等不同作用。
Objective To investigate the regulatory role that Mycobacterium tuberculosis with different levels of virulence plays in macrophage stress in an infected host. Methods Mouse macrophages (RAW264. 7 cells) were infected with myeobacterium tuberculosis H37Rv and Bacillus Calmette Guerin (BCG). Changes in the activity of cellular superoxide dismutase (SOD) and nitric oxide synthase (NOS) and levels of cellular malondialdehyde (MDA) and nitric oxide (NO) were detected using chemical eolorimetry 1 h, 6 h, 12 h, and 24 h post infection. Results Twenty four hours a{ ter infection with BCG, the cellular activity of SOD (32.82±0.54) U/ml and NOS (12. 16±0.29 U/ml) and the level of NO (116.42±3. 23μmol/L) gradually increased whereas the level of MDA (0. 59±0. 08 nmol/ml) decreased in RAW264.7 cells. However, 24 hours after infection with H37Rv, the cellular activity of SOD (15.90±0.20 U/ml) and NOS (2.32±0. 11 U/ml) and the level of NO (13.74±1.01 μmol/L) gradually decreased whereas the level of MDA (5.21_+0.39 nmol/ml) increased in RAW264.7 cells. The differences were statistically significant compared to the con trol group (P〈O. 05). Conclusion Less virulent and more virulent M. tuberculosis play different roles in inducing and inhibiting macrophage stress in an infected host.