FIGURE 3.
Histological analysis of Pkd1Oc-cKO mice in bone. A, Goldner and von Kossa staining of non-decalcified bone. Representative images of distal femur and lumbar vertebrate sections displayed markedly reductions in trabecular bone volume from 16-week-old Pkd1Oc-cko mice compared with age-matched control mice. Scale bars, 200 μm. B, bone histomorphometric analyses. There was a significant reduction in periosteal MAR, MS/BS, and BFR in single Oc-Cre;Pkd1flox/+ and Pkd1m1Bei/+ heterozygous mice compared with age-matched control Pkd1flox/+ mice and an even greater decrement in double heterozygous Pkd1Oc-cko mice, indicating an additive effect of both global and conditional Pkd1 deficiency to impair osteoblast-mediated bone formation. Representative images of the distal tibia-fibula junction sections from 16-week-old mice for each genotype showed progressive reductions in the distance between the two calcein labels (scale bars, 20 μm). C, Oil Red O staining of decalcified femur sections. Representative images of femoral bone marrow showed that the numbers of adipocytes and fat droplets were greater in 18-week-old Pkd1Oc-cko mice compared with age-matched control mice. Scale bars, 100 and 500 μm. D, OsO4 staining of decalcified tibias by μCT analyses. Qualitatively, the images of osmium staining (white or red areas) were much higher in the proximal tibia from 18-week-old Pkd1Oc-cko mice compared with age-matched control mice. Quantifications of fat cell number and volume were also performed as described under “Experimental Procedures.” Ad.V/Ma.V (%), adipocyte volume/marrow volume; Ad.N (mm−3), adipocyte number (mm−3). Scale bars, 1.0 mm. Data are mean ± S.D. from 3–5 individual mice. *, significant difference from control (Pkd1flox/+); @, significant difference from single heterozygous Oc-Cre;Pkd1flox/+; #, significant difference from single heterozygous Oc-Cre;Pkd1flox/+ and Pkd1flox/m1Bei mice at p < 0.05, respectively.