Intermittent Parathyroid Hormone Administration Stimulates Bone Formation in the Mandibles of Aged Ovariectomized Rats

Abstract

Intermittent administration of parathyroid hormone (PTH) is known to stimulate bone formation in many skeletal sites and is being investigated as a possible therapeutic agent for the treatment of osteopenic conditions, including post-menopausal osteoporosis. The purpose of this study was to determine the ability of PTH to stimulate bone formation in the mandibles of aged ovariectomized (Ovx) rats, and the results are compared with a site in the appendicular skeleton (humerus). The Ovx rat is a useful model of estrogen deficiency, replicating many aspects of post-menopausal osteoporosis. Female rats were ovariectomized or sham-operated, and one year later a group of the ovariectomized rats was treated with the 1-34 fragment of human PTH daily, five days a week for 10 weeks. During the experiment, the animals were given fluorochrome bone markers for histomorphometry. More than one year after ovariectomy or sham surgery, there were few differences in the histomorphometric indices of bone formation in the humerus or mandible. PTH treatment had no effect on dentin formation, measured in the mandibular incisor; however, most indices of bone formation-including the double-labeled surface, mineralizing surface, mineral appositional rate, new bone area, and surface-referent bone formation rates-were substantially greater in the PTH-treated group compared with both the Ovx and the Sham controls measured at the periosteal and endocortical surfaces of the humerus and the periosteal and cancellous bone surfaces of the mandible. In addition, bone formation at the alveolar crest, particularly on the buccal side, was greater in the PTH-treated group. The results from this study demonstrate that systemic intermittent PTH treatment stimulates bone formation in the mandibles in aged, estrogen-deficient animals.

Teriparatide and the treatment of bisphosphonate-related osteonecrosis of the jaw: a rat model

“…Intermittent parathyroid hormone administration was also shown to induce an increase in alveolar bone formation in rats. 25 In the present study, alveolar bone width of the ZA group was found to be greater than that of the control group. This finding might be the result of the inductive effect of BRONJ lesion on periosteal new bone formation.…”

Effect of an Intermittent Weekly Dose of Human Parathyroid Hormone (1-34) on Osteoporosis: A Randomized Double-Masked Prospective Study Using Three Dose Levels

“…In animal studies the anabolic action of PTH has frequently been confirmed [13][14][15][16][17][18][19][20] and improvement in the physical properties of the bone reported [21]. Such an anabolic action appears to depend on the intact Nterminal portion of PTH, since the effect almost disappeared on removal of one N-terminal amino acid [22][23].…”

A review on endogenous regenerative technology in periodontal regenerative medicine

“…Because one of the basic characteristics of periodontitis is the resorption of alveolar bone, it was hypothesized that PTH could inhibit bone resorption and promote alveolar bone regeneration, thereby representing a promising potential technique for improving the outcome of periodontal therapy. Miller et al (1997) administered intermittent PTH to the mandibles of aged ovariectomized rats and found that PTH stimulated bone formation in the mandible [237]. Similarly, using a ligature-induced periodontitis model in rodents, another group found that PTH protects against periodontitis-associated bone loss [238].…”