[Frontiers in vitamin D; basic research and clinical application. A review on histological findings in bones...

This review will show the histological findings in femora of ovariectomized (OVX) rats administered with or without eldecalcitol, a second-generation of vitamin D analog, which were published in our recent article. The OVX group showed markedly-reduced bone mineral density, and the decreased trabecular number and thickness, which was consistent to increased osteoclastic number and bone resorption parameters. After eldecalcitol administration, the number of osteoclasts was diminished, accompanied with elevated bone mineral density. Interestingly, eldecalcitol did promote a type of focal bone formation that is independent of bone resorption, a process known as bone mini-modeling. Taken together, our findings suggest that eldecalcitol mainly inhibits osteoclastic bone resorption, but, in part, stimulates focal bone formation in the OVX bone.