Macrophage deletion of murine Fpn1 with LysM-Cre. (A) Southern blot analysis of LysM-cre mediated excision of Fpn1^flox/flox genomic DNA in BMDMs. (B) Relative Fpn1 mRNA levels in BMDMs from Fpn1^flox/flox or Fpn1^LysM/LysM mice were measured by quantitative RT-PCR. Results were normalized to the internal control β-actin and presented as relative expression level calculated by the 2^ΔΔC_t method and presented as mean plus or minus SEM; n = 4. *P < .05. (C) Fpn1 protein levels in BMDMs from Fpn1^flox/flox or Fpn1^LysM/LysM mice were assessed by Western blot analysis. (D) Detection of Fpn1 expression (arrowheads). Paraffin sections of tissues from Fpn1^flox/flox or Fpn1^LysM/LysM mice were stained with a rabbit anti-Fpn1 primary antibody and goat anti–rabbit IgG-horseradish peroxidase secondary antibody. Scale bar represents 50 μm.