Figure 6.

SP-D deficiency increases tubular cell apoptosis and caspase-3 activation in the kidney of bacterial pneumonia. (A) Representative images of TUNEL assay in the kidney of sham and infected mice 48 h after P. aeruginosa infection. The apoptotic cells showed green (blue color for nuclei). A large number of apoptotic cells are observed in the kidneys of all infected mice but not in the Sham mice. Original magnification 200×. Scale bars = 100 μm. (B) Apoptotic cells were quantified by counting apoptotic cells per high power field. The numbers of TUNEL-positive cells in the kidney of infected KO and hTG mice are larger than that of infected WT mice. Infected KO mice exhibit more apoptotic cells than hTG mice. *p < 0.05, **p < 0.01, One-way ANOVA, Newman-Keuls multiple comparison post hoc test (n = 6/group). (C) IHC assay for cleaved caspase-3 in the kidneys from Sham and infected mice. The positive staining of activated caspase-3 was characterized by cytoplasmic and perinuclear localization of brown-yellow color reaction. Caspase-3 was significantly activated and expressed on the proximal renal tubules only in infected mice but not in sham mice. Aactivated caspase-3 expression was more prominent in infected KO and hTG mice than infected WT mice. (D) Western blot analysis of cleaved caspase-3 expression in the kidney. Semi-quantitative analysis indicated that the level of activated caspase-3 (17 kDa) was higher in infected KO mice vs hTG or WT mice and in infected hTG vs WT mice. *p < 0.05, **p < 0.01, One-way ANOVA, Newman-Keuls multiple comparison post hoc test (n = 3/group). Sham = Sham infection, Pneu = Pneumonia.