建立双膦酸盐性颌骨坏死动物模型

Establishing an animal model of bisphosphonate-related osteonecrosis of the jaw

背景:大部分双膦酸盐性颌骨坏死者由于拔牙、种植等颌骨创伤引起,创口不愈合,并发感染流脓,疼痛不适,最终死骨形成,其致病机制尚不清楚。目的:建立成熟稳定的双膦酸盐性颌骨坏死动物模型,观察双膦酸盐性颌骨坏死的临床表现、影像学改变及组织病理学特点,为进一步探讨双膦酸盐性颌骨坏死的致病机制奠定基础。方法:24只雌性SD大鼠随机分为2组,每组12只。实验组腹腔注射唑来膦酸(0.2 mg/kg),每周3次持续12周;对照组腹腔注射等量生理盐水,每周3次持续12周。12周后所有大鼠麻醉下拔除左下第1磨牙,临床观察拔牙创愈合情况。拔牙后8周所有动物安乐死。对大鼠左下颌骨进行X射线片检查和Micro-CT检查,探究其影像学改变。对下颌骨软硬组织进行苏木精-伊红染色和Masson染色,探究其组织病理学特点,进一步确定双膦酸盐性颌骨坏死动物模型。结果与结论:(1)拔牙后8周,临床观察发现实验组大鼠拔牙创不愈合,并且实验动物口内可见死骨暴露;(2)影像学检查及组织病理学检查均证实双膦酸盐性颌骨坏死的发生;(3)组织学染色结果显示实验组拔牙创周围牙龈胶原纤维纤细;(4)结果说明,腹腔注射唑来膦酸联合拔牙的方法能够成功诱导大鼠发生双膦酸盐性颌骨坏死样病变。唑来膦酸的软组织毒性及抗血管形成作用能够促进双膦酸盐性颌骨坏死发生,创伤带来的酸性局部微环境也提高了发生双膦酸盐性颌骨坏死的可能性。

BACKGROUND:Bisphosphonates-related osteonecrosis of the jaw(BRONJ)is thought to be caused by trauma to dentoalveolar structures after dental extraction and implantation that have a limited capacity for bone healing followed by infection,suppuration and pain,further inducing equestration,but the pathogenesis is poorly understood.OBJECTIVE:To establish a stable animal model of BRONJ,and to observe its clinical manifestations,radiological changes and pathological characters,thereby paving ways for further understanding the pathogenesis of BRONJ.METHODS:Twenty-four female Sprague-Dawely rats were randomly allocated into experimental and control groups(n=12per group).The rats in the experimental group were given the intraperitoneal injection of0.2mg/kg zoledronic acid,and the controls received the intraperitoneal injection of same volume of normal saline,three times weekly for consecutive12weeks.Subsequently,left first mandibular molars were extracted under general anesthesia,and the bone healing was observed.At8weeks after tooth extraction,all the rats were euthanized.The rat left jaws were examined byX-ray and micro-CT to explore the imaging changes.The histopathological characteristics of the mandibular soft and hard tissues were investigated by hematoxylin-eosin staining and Masson staining,to further testify the BRONJ model.RESULTS AND CONCLUSION:At8weeks after tooth extraction,the wound was unable to heal,and nonvital bone tissues were visible in the experimental group.The findings revealed on radiographies and pathological sections were in accordance with the characteristics of BRONJ.Masson staining results showed slender collagen fibrils around the dental extraction wound were slender in the experimental group.These results indicate that the intraperitoneal injection of zoledronate combined with tooth extraction can induce BRONJ in rats.The soft tissue toxicity and anti-angiogenesis of zoledronic acid can promote the occurrence of BRONJ,and the local acidic microenvironment caused by trauma probably is involved in the occurrence of BRONJ.