[Long-term and high-dose bisphosphonate administration causes no bone over-mineralization].
OBJECTIVE
To evaluate the effects of long-term bisphosphonate administration (incadronate) upon the mean degree of secondary bone mineralization.


METHODS
Thirty adult beagles were divided randomly into three groups of CNT, YML and YMH based upon their body weights (5 males and 5 females in each group). Animals in CNT were orally given lactose 12 mg x kg(-1) x d(-1) while those in YML and YMH were orally given incadronate disodium at doses of 0.3 mg x kg(-1) x d(-1) and 0.6 mg x kg(-1) x d(-1) respectively. The dosing procedure lasted for three years. Prior to sacrifices, all animals were double-labeled intravenously with oxytetracycline hydrochloride (20 mg x kg(-1)). After necropsy, the left 9th ribs were excised for evaluation.


RESULTS
Histomorphometry showed that activation frequency in YML and YMH [(4.93 +/- 0.92)/mm(2) and (2.50 +/- 0.78)/mm(2)] were significantly lower than that in CNT (7.83 +/- 0.96)/mm(2) per year. The mean degree of mineralization in bone in YML and YMH (1.40 +/- 0.12, 1.48 +/- 0.09) were significantly higher than CNT (1.07 +/- 0.06). The increments were 31% and 38% respectively.


CONCLUSIONS
Long-term and high-dose bisphosphonate administration significantly suppresses bone turnover so as to increase the degree of bone mineralization. But there is no resulting bone over-mineralization. (incadronate) administration on the mean degree of secondary mineralization in bone.
Department of Orthopedics, Peking University First Hospital, Beijing, China.
Chao
C
Liu
Yong-ping
YP
Cao
Xin
X
Yang
Tasuku
T
Mashiba
Satoshi
S
Mori
D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects* / Q000502:physiology*; D002113:Calcification, Physiologic / Q000187:drug effects*; D004164:Diphosphonates / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D008297:Male
D004164:Diphosphonates; C071542:cimadronate