Background: The immunology characteristics of the rat model of tuberculosis (TB) infection are still unclear. This study aimed to evaluate the dynamics of pathology and cytokines in a rat model infected with Mycobacterium TB (MTB).
Methods: Sixty male Wistar rats were divided into four groups, namely the control group (without MTB infection) and the MTB -induced group (observations at week-3, week-6, and week-12 postinfection). Granuloma formation was analyzed by histology procedure. Analysis of the levels of tumor necrosis factor-a (TNF-α), interleukin-6 (IL-6), IL-17, IL-2, IL-4, and IL-12 was performed using an enzyme-linked immunosorbent assay technique.
Results: The number and size of the ganulomas increased proportionally between weeks 6 and 12 postinfection. Several cytokines, namely IL-6, IL-17, IL-2, IL-4, and IL-12 significantly increased in the 6th week compared to the 3rd week after infection (P < 0.05). These cytokines decreased significantly at the 12th week compared to the 6th week (P < 0.05). TNF-α was found to be stable at the third and 6th weeks and then decreased at the twelfth postinfection week. For IL-12, the longer the infection time, the higher the level.
Conclusions: It was concluded that there was a typical pattern of TB infection in Wistar rats, namely certain cytokines that peaked at week 6 of infection. Thus, TB infection in rats can be a model for early-phase TB study.
Keywords: Experimental animal models; granuloma; immunology; pathology; pulmonary tuberculosis.