title: Impact of Actinomyces naeslundii on bisphosphonate-related osteonecrosis of the jaws in ovariectomized rats with periodontitis.
abstract: Bisphosphonates-related osteonecrosis of the jaws (BRONJ) is a severe complication of BPs therapy with unknown pathogenesis. This study aimed to evaluate the impact of Actinomyces naeslundii (A. naeslundii) on the progression of BRONJ in ovariectomized (OVX) rat model with periodontal diseases. Sixty rats were randomly assigned into four groups. All rats underwent bilateral ovariectomy. Six weeks after surgery, animals with periodontitis induced by ligature placement were administrated with normal saline (NS), NS &A. naeslundii inoculation, zolecdronic acid (ZA) and ZA &A. naeslundii inoculation for 12 weeks, respectively. Loads of total bacteria and A. naeslundii in the mouth were assessed by real time PCR. After sacrifice, the mandibles were harvested for micro-computed tomography (micro-CT) and histological examination. Real-time PCR demonstrated that A. naeslundii was not routinely found in the rats and ZA treatment did not promote its accumulation. Micro-CT examination disclosed that ligature placement induced significant alveolar bone loss, which was greatly attenuated by ZA treatment and aggravated by A. naeslundii. Histological assessment demonstrated that ZA treatment increased the risk of developing BRONJ-like disease but this condition was not worsen with the presence of A. naeslundii. Our study suggested that oral A. naeslundii inoculation aggravated periodontal disease but not BRONJ in our animal model.
authors: Discipline of Oral Diagnosis & Polyclinics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China; Department of Oral Medicine, Peking University School & Hospital of Stamotology, Beijing, China.
authors: Chun Lei
authors: CL
authors: Li
authors: Discipline of Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore.
authors: Chaminda Jayampath
authors: CJ
authors: Seneviratne
authors: Discipline of Oral Diagnosis & Polyclinics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
authors: Lei
authors: L
authors: Huo
authors: Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors: Weijia William
authors: WW
authors: Lu
authors: Discipline of Oral Diagnosis & Polyclinics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Electronic address: lwzheng@hku.hk.
authors: Li Wu
authors: LW
authors: Zheng
mesh_terms: D000190:Actinomyces / Q000502:physiology*; D000196:Actinomycosis / Q000382:microbiology*; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000382:microbiology; D000818:Animals; D058491:Bacterial Load; D059266:Bisphosphonate-Associated Osteonecrosis of the Jaw / Q000000981:diagnostic imaging / Q000382:microbiology*; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000008:administration & dosage; D000071556:Cancellous Bone / Q000000981:diagnostic imaging; D004164:Diphosphonates / Q000008:administration & dosage; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000382:microbiology; D010052:Ovariectomy / Q000379:methods*; D010518:Periodontitis / Q000000981:diagnostic imaging / Q000382:microbiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D055114:X-Ray Microtomography / Q000379:methods; D000077211:Zoledronic Acid
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007093:Imidazoles; D000077211:Zoledronic Acid
keywords: Actinomyces naeslundii; Bisphosphonates-related osteonecrosis of the jaws; ovariectomy; periodontal diseases; rat