Evaluation of periapical lesions induced in female osteoporotic rats subjected or not to treatment with bisphosphonate or cathepsin K inhibitor

Abstract

The aim of this study will be to evaluate periapical lesions induced in female osteoporotic rats subjected or not to treatment with bisphosphonate (alendronate - ALD) or cathepsin K inhibitor (odanacatib - ODN). Fifty animals will be randomly assigned to 6 groups: I - Sham surgery; II - Sham and periapical lesion; III - ovariectomy (OVX) and periapical lesion; IV - OVX, periapical lesion and ALD; V - OVX, periapical lesion and ODN; Group VI - OVX, periapical lesion and distilled water. Four weeks after OVX or sham surgery, groups IV, V and VI animals will start receiving medication or distilled water and the mandibular first molars of the rats in groups II, III, IV, V and VI will be subjected to induction of periapical lesion formation. Twenty-one days later, microbiological root canal sampling will be performed for quantification of microorganisms and the animals will be euthanized. Mineral bone density of the tibias of all animals will be evaluated. The left hemi-mandibles will be subjected to histotechnical processing and the hematoxylin and eosin-stained histological sections will be examined under conventional optical microscopy. Additionally, it will be performed morphometric analysis of periapical lesion size, tartrate-resistant acid phosphatase (TRAP) histoenzymology for identification of osteoclasts, Brown and Brenn staining for identification and localization of bacteria, and immunohistochemical analysis of osteoclastogenesis and cathepsin K markers. The right hemi-mandibles will be used for detecting of the expression of cytokines, osteoclastogenesis markers and matrix metalloproteinases by real-time polymerase chain reaction (RT-PCR). The results will be analyzed statistically using appropriate tests with a significance level of 5%. (AU)