Restoring effect of human parathyroid hormone (1-34) on trabecular connectivity in ovariectomized rats.
The purpose of this study was to determine if the loss of the trabecular connectivities can be recovered by human parathyroid hormone-(1-34) therapy in ovariectomized (OVX) rats. Seven-month old female Wistar rats underwent ovariectomy or sham-operation at the beginning of the experiment. All sham operated groups (sham groups) were sacrificed after 0 (initial-BL group), 4, 8, 12, and 16 weeks, and one-third of the OVX rats were sacrificed as the baseline controls (OVX-BL groups) at 4, 8, and 12 weeks after OVX. Four weeks PTH or its vehicle treatment for residual OVX rats was started at 4, 8, or 12 weeks after OVX (OVX+PTH groups, OVX+vehicle groups). h-PTH (6.0 microg/kg) was injected subcutaneously six times a week for 4 weeks for each group. Their proximal right tibiae were processed for undecalcified Villanueva bone staining sections for bone histomorphometry. Furthermore, changes in trabecular connectivities were determined by node-strut analysis. h-PTH completely restored OVX-induced cancellous bone loss by stimulating bone formation. In node-strut analysis, node number in the OVX-BL-4, -8, and -12 groups was decreased to 53%, 49% and 44% of the initial-BL value respectively, and that in the OVX-4, -8, -12 + PTH groups recovered to 80%, 66%, 56% of the initial-BL value respectively. However, they were lower than those in their corresponding sham groups. The findings of this study suggested that decreased trabecular connectivity by OVX was recovered by intermittent h-PTH administration. However, delayed treatment blunted the restoration of trabecular connectivity.
Tsuchida
T
T
Department of Orthopedic Surgery, Akita University School of Medicine, Japan. tsuchy@ma4.justnet.ne.jp
Miyakoshi
N
N
Kudo
T
T
Tamura
Y
Y
Kasukawa
Y
Y
Suzuki
K
K
Sato
K
K
D000818:Animals; D001862:Bone Resorption / Q000188:drug therapy / Q000473:pathology; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy / Q000473:pathology; D010052:Ovariectomy / Q000009:adverse effects*; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D010281:Parathyroid Hormone; D010446:Peptide Fragments