Figure 5: Both PTH (1-34) and abaloparatide increased bone resorption in mice.

At the end of the treatments, mice were killed at 4 or 18 h after the last injections. To assess bone resorption, A) serum CTX levels were measured by ELISA in male mice treated with PTH (1-34) or abaloparatide. B-C) Femurs were fixed in 70% ethanol, dehydrated and embedded in methacrylate. TRAP staining was done in order to count osteoclasts on bone surfaces, B) in trabecular area and, C) in cortical bone in the mid-diaphysis. Two tibiae from each animal were divided into subcortical trabecular-rich bone, bone marrow and cortical bone (osteocyte-rich bone). Total RNA was isolated and qRT-PCR was performed. Catabolic gene expression was measured in the trabecular-rich fraction for D) Rankl/Opg ratio, E) Mmp13, F) c-fos and in cortical bone for G) Rankl/Opg ratio, H) Mmp13, I) c-fos. Expression of all genes was compared with housekeeping genes and shown as fold change compared with control animals. 5-10 mice per group, results are means ± SD. All data were analyzed for normality and equivalence of variance. For histomorphometry analyses, we used a 1 way ANOVA followed by Tukey’s multiple comparison test. For the qPCR and CTX analyses, normal distribution was not achieved so rank transformation was performed before new normality and equivalence of variance tests were done and 2 way ANOVA followed by Bonferroni’s multiple comparison test was then conducted. All exact p values are shown.