Figure 5. Lung histopathology and Mtb granuloma formation is unaltered in Nlrp12 deficient mice.

Histopathological analyses of lung sections were conducted at 14, 26 and 181 days post infection (DPI) with aerosol Mtb. A) Semiquantative histology scoring revealed a similar increase in lung inflammation over the course of the Mtb infection between Nlrp12^−/− and wild type mice. B) Histopathological progression of leukocyte infiltration at 14, 26 and 181 DPI. Mild to moderate perivascular cuffing was observed around the vasculature of the lungs by 14 DPI. Extensive leukocyte infiltration around the vasculature, airways and throughout the lung parachema was observed by 26 DPI. Large, well formed granulomas were observed at 181 days post infection, which affected extensive regions of the lungs. No signs of abnormal inflammation or granuloma formation were detected in the saline treated mice at any time point evaluated. The magnification bar at 20× = 10 µM and 40× = 5 µM. C) Images from acid fast stained lung sections revealed that the leukocyte infiltration was associated with concentrated areas of bacteria infiltration and was consistent with early stage granuloma formation. The magnification bar at 60× = 5 µM. D–E) The number of granulomas per lung and the size of each granuloma was determined and no significant differences in granuloma formation was observed between either Nlrp12^−/− or wild type mice. Experiments were repeated 2 separate times with a minimum of 12 Mtb infected Nlrp12^−/− and 12 wild type mice in each group. At least 3 mice per strain per time-point were used for analysis.