Fig 5.

Influence of disruption of bfrA and bfrB genes of M. tuberculosis on gross pathological lesions and histopathological damage in organs of infected guinea pigs. The figure depicts representative photographs of gross pathological lesions in lung, liver, and spleen of guinea pigs (n = 6) infected with M. tuberculosis (WT) and H37Rv ΔbfrA ΔbfrB (AB) euthanized at 10 (A) and 16 (B) weeks postinfection. Guinea pigs infected with H37Rv ΔbfrAΔbfrB resulted in fewer and smaller lung, liver, and spleen lesions compared to animals infected with M. tuberculosis. Each data point represents the score of an individual animal, and the bars depict medians (± interquartile ranges) for each group. Missing data points represent the animals that succumbed to disease before the time of euthanasia. *, P < 0.05; **, P < 0.01; ***, P < 0.001 (Student's t test). (C) Influence of the disruption of bfrA and bfrB genes of M. tuberculosis on the histopathological damage to the organs of infected guinea pigs. The lung tissues were fixed in 10% buffered formalin and were embedded in paraffin. Subsequently, 5-μm-thick sections were cut and stained with hematoxylin and eosin (H&E) for histopathological examination. The figure depicts a representative photograph of the extent of pathological damage to animals (n = 6) infected with either M. tuberculosis (A) or H37Rv ΔbfrA ΔbfrB (B) at ×40 magnification at 10 weeks postinfection. H37Rv ΔbfrA ΔbfrB-infected animals showed reduced granulomatous infiltration, with only a few small and discrete granulomas, compared to that of M. tuberculosis-infected animals.