FIG. 5.

Intermittent PTH increased bone mass in Bcl2 ^−/− tibias and vossicles. PTH was administered daily to Bcl2 ^+/+ and Bcl2 ^−/− mice from day 4 to day 12, and the proximal one third of each tibia was selected for analysis. (A) Representative micrographs of H&E-stained tibias. Substantial trabecular bone was noted in PTH-administered groups regardless of genotype (n > 15/group). (B) Representative μCT images with summary data below. In both genotypes, considerably more trabecular bone was found in PTH-administered groups vs. controls (n = 5/group). Regardless of genotype, intermittent PTH administration induced significantly higher bone volume fraction than vehicle. (C) Vertebrae from Bcl2 ^+/+ and Bcl2 ^−/− mice were subcutaneously implanted into athymic mice, and PTH was administered daily for 21 days. Representative micrographs of H&E-stained vossicle sections with summary data below. Enhanced trabeculation was found in PTH-administered groups regardless of genotype. Controls exhibit sparse trabeculation in both genotypes. Bone area (%) was significantly higher in the PTH-administered group than vehicle control regardless of genotype. No difference was found in bone area (%) between Bcl2 ^+/+ and Bcl2 ^−/−, irrespective of treatment (n > 23/group). (D) Representative μCT images with summary statistics below. Intermittent PTH administration significantly enhanced bone in vossicles of both genotypes. Little trabecular structure was noted in controls regardless of genotype (n = 4/group). *p < 0.05, **p < 0.01, ***p < 0.001.