Fig. 7. Static bone histomorphometric analysis after a 4-week treatment with 40 µg/kg PTH. (A-C) Trichrome Masson stain of the proximal tibia showing less abundant trabecular bone mass in the conditional knockout (cKO) ColCre;Cx43^–/fl relative to heterozygous equivalent (Het) Cx43^–/fl and wild-type (WT) Cx43^+/fl mice. (D) Robust anabolic response occurred in the WT group, and an attenuated response was observed in Het mice. By contrast, no significant increases in bone volume/total volume were detected in the conditionally deleted ColCre;Cx43^–/fl mice relative to the other genotype groups. (E) Osteoblast number was significantly increased by PTH treatment in all groups. (F) Trabecular number was significantly increased in the wild-type groups only. (G) The same result was observed for trabecular thickness. (H) No significant changes were detected for cortical thickness. (I) Osteoclast number was not different among the different groups. *P<0.05 versus vehicle (ANOVA); n=9-15.