Pamidronate increases trabecular bone mineral density in immobilization osteopenia in male rats.
OBJECTIVE
Osteopenia is a common consequence of immobilization. We investigated the effects of pamidronate on immobilized bone in male rats.


METHODS
Eighty male Wistar rats (5 months old) were divided in five groups (control (C); pamidronate at 0.5 mg/kg per dose (Pam0.5); immobilization (N); pamidronate at 0.05 mg/kg per dose + immobilization (N + Pam0.05); and pamidronate at 0.5 mg/kg per dose + immobilization (N + Pam0.5). The rats were immobilized on their right side by sciatic neurectomy. Pamidronate was given subcutaneously three times a week for three weeks. Trabecular bone mineral density (TBMD) of the upper femur, ultimate failure load of the femoral diaphysis, ash weight of femur, calcium content of femoral ash, and ash weight corrected with bone volume (AWcc [g/cm3]) were determined. Histomorphometry of proximal tibiae was performed by a semiautomatic method.


RESULTS
TBMD was higher on both sides in Pam0.5 and N + Pam0.5 groups than in C or N groups. Ultimate failure load was not altered significantly with treatment. AWcc of the immobilized femur was lower (p < 0.001) than in the contralateral limb in N, N + Pam0.05 and N + Pam0.5 groups. Both resorption and formation parameters were suppressed by pamidronate.


CONCLUSIONS
Pamidronate treatment seemed to increase trabecular bone density, although it was not effective in maintaining the AWcc of the operated extremity. Pamidronate did not seem to affect the ultimate failure load of cortical bone.
Huuskonen
J
J
Department of Surgery, University of Kuopio, Finland. johuusko@hytti.uku.fi
Arnala
I
I
Olkkonen
H
H
Alhava
E
E
D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D001851:Bone Diseases, Metabolic / Q000188:drug therapy* / Q000209:etiology*; D004164:Diphosphonates / Q000494:pharmacology / Q000627:therapeutic use*; D005269:Femur / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D007103:Immobilization / Q000009:adverse effects*; D008297:Male; D000077268:Pamidronate; D051381:Rats; D017208:Rats, Wistar
D004164:Diphosphonates; D000077268:Pamidronate