Clodronate stimulates bone formation as well as inhibits bone resorption and increases bone mineral density in rats fed a low-calcium diet.
The pharmacological actions of bisphosphonates are due to the inhibitory effects on bone resorption, but little is known about the bisphosphonate action on bone formation. The purpose of this study is to elucidate the actions of bisphosphonates, clodronate, on bone formation in the experimental in vivo and in vitro rat models. The bone mineral density (BMD) was decreased in the rats fed a low-calcium diet (0.05% Ca) for 6 days compared with the rats fed a normal-calcium diet (0.5% Ca). The decrease in BMD was suppressed in the 2 mgP/day and the 4 mgP/day clodronate administrations. Bone formation rate (BFR) in rats fed a low-calcium diet was significantly increased compared with the rats fed a normal-calcium diet, and the 2 mgP clodronate administration further increased the BFR. In the cultured rat bone marrow cells, the area of mineralized nodules was significantly increased at 10(-7) and 10(-6) M clodronate, but high concentration of clodronate decreased the area. From these results, it is concluded that clodronate stimulates bone formation when the drug was given to a rat with a relatively lower dose that is sufficient to prevent bone resorption and that this effect may be due to the stimulatory effect on the differentiation process of osteoblasts.
Horie
Daisuke
D
Pharmacology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Takahashi
Mariko
M
Aoki
Kazuhiro
K
Ohya
Keiichi
K
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D015152:Blotting, Northern; D015519:Bone Density / Q000187:drug effects; D001854:Bone Marrow Cells / Q000187:drug effects; D001862:Bone Resorption / Q000517:prevention & control*; D002118:Calcium / Q000172:deficiency*; D002478:Cells, Cultured; D004002:Clodronic Acid / Q000494:pharmacology* / Q000627:therapeutic use; D024042:Collagen Type I / Q000096:biosynthesis; D008297:Male; D010006:Osteoblasts / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar
D024042:Collagen Type I; D012333:RNA, Messenger; D004002:Clodronic Acid; D000469:Alkaline Phosphatase; D002118:Calcium