Efficacy of pyrazinoic acid dry powder aerosols in resolving necrotic and non-necrotic granulomas in a guinea pig model of tuberculosis - Fig 3

Images of A) lung, B) spleen, and C) liver histopathologic lesions. Animals were infected with M. tuberculosis for four weeks and treated for an additional four weeks with treatment as noted. At eight weeks post-infection, guinea pigs were sacrificed, tissues collected, sectioned and H&E stained. Lungs contained randomly distributed, variably progressed granulomas. While all treatment groups had necrotic granulomas (arrowhead), the untreated group and the R-PDP treatment group had a higher percentage of non-necrotic granulomas (asterisk). The white pulp of spleens is expanded and effaced by granulomatous inflammation (arrows), which appears pale adjacent to the dark basophilic, peripheralized lymphoid follicles. The livers of untreated animals contained large granulomas (outlined) and some livers of R-PAE and RIF (R) treated animals occasionally contained smaller granulomas. Tissues from an age matched representative uninfected guinea pig is included for comparison Bars, 1mm (lung); 1mm (spleen), 500 μm (liver). Images are 40X, 40X and 100X magnification for lung, spleen and liver tissues, respectively.