This figure shows a set of whole mount images of tissues from wild-type and CSF1R knockout rats.  The rats also have a Csf1r-mApple transgene, so that all of the macrophages are fluorescent.  These images highlight the abundance of tissue macrophages, their regular distribution and their dependence upon CSF1R.

The CSF1R knockout rats have a severe postnatal growth retardation and delayed development of many major organs including male and female reproductive tissues.  The tissue macrophage populations and the development phenotype can be rescued by transfer of wild-type bone marrow cells at weaning.  Images below show an adult Csf1r-knockout rat and the successful generation of pups from mating of a rescued male and female.

CSF1R-dependent macrophages control postnatal somatic growth and organ maturation. Keshvari S, Caruso M, Teakle N, Batoon L, Sehgal A, Patkar OL, Ferrari-Cestari M, Snell CE, Chen C, Stevenson A, Davis FM, Bush SJ, Pridans C, Summers KM, Pettit AR, Irvine KM, Hume DA.PLoS Genet. 2021 Jun 3;17(6):e1009605. doi: 10.1371/journal.pgen.1009605. eCollection 2021 Jun.PMID: 34081701