Protective Effects of Follicle-stimulating Hormone Inhibitor on Alveolar Bone Loss Resulting from Experimental Periapical Lesions in Ovariectomized Rats

Introduction: The direct effect of follicle-stimulating hormone (FSH) on bone resorption has been demonstrated recently. The aim of this study was to evaluate the effect of FSH inhibitor leuprorelin (LE) on alveolar bone loss resulting from experimental periapical lesions in ovariectomized (OVX) rats. Methods: Twenty-seven female rats were randomly assigned into 4 groups and subjected to ovariectomy or sham surgery (1.6 mg/kg body weight LE or vehicle was injected immediately). One week after surgery, the pulp of each rat's bilateral lower first molars was exposed to the oral environment. Three weeks after pulpal exposure, all the animals were killed, and bilateral mandibles were extracted for histologic processing. Radiographic and histologic examination for periapical bone loss area, enzyme histochemical examination for tartrate-resistant acid phosphatase (TRAP), and immunohistochemical examination for FSH receptor (FSHR) were performed. Results: LE significantly decreased the alveolar bone loss area and osteoclast occurrence compared with non LE treatment ovariectomized rats (P < .05), and the number of FSHR-positive cells was significantly correlated with alveolar bone loss area (r = 0.796, P < .01). Conclusions: LE has protective effects on alveolar bone loss resulting from experimental periapical lesions in OVX rats. (J Endod 2010;36:658-663)