Intermittent Administration of Parathyroid Hormone Ameliorates Periapical Lesions in Mice

Abstract

Introduction Intermittent administration of parathyroid hormone (PTH) promotes oral osseous wound healing and protects against ligature-induced alveolar bone loss. However, its therapeutic value on periapical periodontitis is unknown. The goal of this study was to determine the effect of intermittent PTH administration on the progression of periapical periodontitis. Methods Seven lymphotoxin alpha deficient mice received pulp exposures of mandibular first and second molars. Exposed pulp in the right mandible was covered with plaque-contaminated fibrin, while exposed pulp in the left mandible was left open. After four weeks, the periapical tissues were examined to determine the effect of plaque-contaminated fibrin to induce periapical lesions. Fourteen mice received pulp exposure covered with plaque-contaminated fibrin. PTH (40μg/kg/day) was administered intermittently to half of the mice for three weeks beginning one week after pulp exposure. The remaining half received saline injections as vehicle control. At sacrifice, mandibles and tibiae were harvested and processed for histological examination. Evaluation of neutrophils and blood vessels was performed after staining with immunofluorescence and periradicular bone was histomorphometrically analyzed. Results The exposed pulp covered with plaque-contaminated fibrin resulted in significantly larger periapical lesions compared to control. Intermittent PTH administration reduced the size of periapical lesions significantly. Significantly less neutrophil infiltration around the root apex was found in PTH-treated animals compared to control. Conclusions PTH treatment suppressed periapical inflammation by reducing neutrophil infiltration and protected against tissue destruction by periapical periodontitis.

Intermittent parathyroid hormone promotes cementogenesis in a PKA‐ and ERK1/2‐dependent manner

“…Animals were randomly divided into the experimental (n = 30) and control group (n = 30). Rats in the experimental group received a daily subcutaneous injection of 40 µg/kg body weight PTH (1 to 34) dissolved in 0.1% acetic acid according to previous studies . In the control group, animals received the same volume of placebo vehicle.…”

A New Anabolic compound, LLP2A-Ale, Reserves Periodontal Bone Loss in Mice Through Augmentation of Bone Formation

“…Anabolic treatments, such as teriparatide (human PTH (1-34), which effective against osteoporosis, may also help treat bone loss in both rat and mouse models of PD [33,34]. Interestingly, these previous studies reported antiresorptive and anti-in ammatory mechanisms for daily PTH injections instead of the well-known bone growth effects usually observed for PTH [33,34]. In one clinical trial, the application of PTH combined with periodontal surgery was superior to periodontal surgery alone at repairing localized bone defects [35].…”

A new anabolic compound, LLP2A-Ale, reserves periodontal bone loss in mice through augmentation of bone formation

“…Antiresorptive agents such as BPs are also known for their antiangiogenic actions that potentially are a risk factor for the development of osteonecrosis [33,34]. Anabolic treatments, such as teriparatide (human PTH , which effective against osteoporosis, may also help treat bone loss in both rat and mouse models of PD [35,36]. Interestingly, these previous studies reported antiresorptive and antiin ammatory mechanisms for daily PTH injections instead of the well-known bone growth effects usually observed for PTH [35,36].…”

“…Anabolic treatments, such as teriparatide (human PTH , which effective against osteoporosis, may also help treat bone loss in both rat and mouse models of PD [35,36]. Interestingly, these previous studies reported antiresorptive and antiin ammatory mechanisms for daily PTH injections instead of the well-known bone growth effects usually observed for PTH [35,36]. In one clinical trial, the application of PTH combined with periodontal surgery was superior to periodontal surgery alone at repairing localized bone defects [37].…”