Figure 2

Pasteurella multocida bacteremia accelerates host death by inducing a cytokine storm. A Representative images, H&E staining and Mason’s trichrome staining of PmCQ2-infected murine livers and control murine livers at 36 hpi. The obvious damage areas are indicated by red circles. Scale bar = 200 μm. B Quantification of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in PmCQ2-infected murine serum. Each group contained 5 replicates. N = 5. The data are presented as the means ± SDs. C Representative images of TUNEL staining of control murine livers and PmCQ2-infected murine livers at 36 hpi. The green puncta indicate dead cells. Scale bar = 200 μm. D Representative images of PAS staining of PmCQ2-infected murine kidneys and control murine kidneys at 36 hpi. Scale bar = 100 μm. E Quantification of plasma urea nitrogen (BUN) and serum creatinine (CREA) levels in PmCQ2-infected mice. Each group contained 5 replicates. N = 5. The data are presented as the means ± SDs. F Representative images of immunofluorescence analysis of kidney NGAL expression in PmCQ2-infected mice and control mice at 36 hpi. Scale bar = 100 μm. G Representative images of TUNEL staining of control murine livers and PmCQ2-infected murine kidneys. The green puncta indicate dead cells. Scale bar = 100 μm. H Quantification of IL-6, TNF-α, and IL-1β in the livers and kidneys of mice infected with or without PmCQ2 by ELISA at 24 hpi. N = 5. The data are presented as the means ± SDs. I Quantification of IL-6, TNF-α and IL-1β levels in the serum of mice infected with or without PmCQ2 by ELISA at 24 hpi. N = 5. The data are presented as the means ± SDs. J A schematic of the IL-6 in vivo antibody treatment protocol. On the right are survival curves of mice infected with or without PmCQ2 and treated with 10 μg of an in vivo IL-6 antibody or a rat IgG1 isotype. Each group was composed of 8 mice. Every single point represents one individual. * p < 0.05, ** p < 0.01, *** p < 0.001.