[Study on macrophages infected with Mycobacterium tuberculosis H37Ra in vitro].

Aim: To study the production of nitric oxide and secretion of cytokines after infection of macrophages with Mycobacterium tuberculosis H37Ra.

Methods: 24 hours after infection of RAW264.7 cells with Mycobacterium tuberculosis H37Ra, the production of NO and H(2);O(2); as well as the secretion levels of IL-12 and TNF-α in the supernatants of culture were determined by Griess method, chemical method and ELISA assay respectively. The expression of IL-12 and TNF-α mRNA in macrophages was detected by reverse transcription polymerase chain reaction (RT- PCR).

Results: Macrophages infected with Mycobacterium tuberculosis H37Ra produced effectively more NO, H(2);O(2);, and enhanced the release of IL-12, TNF-α and the expression of IL-12, TNF-α mRNA (P<0.05).

Conclusion: Mycobacterium tuberculosis H37Ra can induce the production of more nitric oxide and cytokines which play important roles in the host immune response.