双膦酸盐相关性颌骨坏死大鼠模型的建立及其对种植体周骨愈合影响的初步研究

Establishment of a Rat Model of Bisphosphonate-Related Osteonecrosis of the Jaw and a preliminary investigation onits impact on peri-implant bone healing

  • 摘要: 背景 双膦酸盐引发的双膦酸盐相关性颌骨坏死(bisphosphonate-related osteonecrosis of the jaw,BRONJ)是临床上无法忽视的严重不良反应,既往建立的BRONJ动物模型在给药途径和剂量上未能准确地模拟临床实际用药环境。目的 模拟临床用药环境建立BRONJ大鼠模型,并探究其对种植体植入后骨结合和骨愈合的影响。方法 将40 只雄性SD大鼠随机分为对照组和模型组,模型组通过模拟临床恶性肿瘤患者的等效用药剂量,尾静脉注射唑来膦酸钠联合地塞米松,对照组给予等量生理盐水,给药4 周后拔除双侧上颌第一磨牙诱导BRONJ。拔牙4 周后随机取各组大鼠拔牙窝样本进行建模评估,剩余大鼠同期进行种植体植入,于种植4 周后取材评估。通过Micro-CT 检测拔牙窝及种植体周骨密度(bone mineral density,BMD)、骨体积分数(bone volume/total volume,BV/TV)、骨小梁数量(trabeculae number,Tb.N)、骨小梁厚度(trabeculae thickness,Tb.Th)以及骨小梁分离度(trabeculae separation,Tb.Sp)等骨愈合指标;通过HE/Masson 染色检测拔牙窝及种植体周骨细胞、炎症细胞、结缔组织和胶原纤维的增生和分布;通过免疫组化染色检测种植体周骨组织相关蛋白碱性磷酸酶(alkaline phosphatase,ALP)、骨形态发生蛋白-2(bone morphogenetic protein-2,BMP-2)、骨钙素(osteocalcin,OCN)、I 型胶原蛋白(type I collagen,COL-1)、骨桥蛋白(osteopontin,OPN)和Runt 相关转录因子2(recombinant runt related transcription factor 2,Runx2)表达。结果 大体观察和Micro-CT 检查发现,模型组拔牙窝及种植体周出现创口不愈、坏死骨暴露、骨愈合指标(BMD、BV/TV、Tb.N、Tb.Th)下降(P<0.01),对照组拔牙窝及种植体周骨愈合良好;HE/Masson染色结果显示模型组拔牙窝及种植体周可见骨组织坏死、炎症细胞浸润,骨细胞胞核溶解,结构不清。对照组愈合良好,可见较多结缔组织及胶原纤维增生;免疫组化结果显示模型组成骨相关基因(ALP、COL-1、BMP-2、OPN)表达下调(P<0.05)。结论 本研究建立了模拟临床用药环境的BRONJ大鼠模型,并初步验证了双膦酸盐对种植体周骨结合与骨愈合可能存在的抑制。

     

    Abstract: Background Bisphosphonate-Related Osteonecrosis of the Jaw(BRONJ) caused by bisphosphonates is a serious adverse reaction that cannot be ignored in clinical practice. The previously established BRONJ animal models have not accurately simulated the actual clinical drug administration environment in terms of administration route and dosage.Objective To establish a BRONJ rat model that simulates the clinical drug administration environment and to explore its impact on osseointegration and bone healing after implant placement.Methods Forty male SD rats were randomly divided into a control group and a model group. The model group was treated with zoledronic acid sodium combined with dexamethasone via tail vein injection to simulate the equivalent drug dosage used in clinical malignant tumor patients. The control group was given the same volume of normal saline. After 4 weeks of administration, the first maxillary molars on both sides were extracted to induce BRONJ. Four weeks after tooth extraction, samples from the extraction sockets of each group were randomly taken for modeling and evaluation. The remaining rats underwent implant placement at the same time, and samples were collected 4 weeks after implantation for evaluation. Micro-CT was used to detect the osseointegration and bone healing indicators (BMD, BV/TV, Tb.N, Tb.Sp, Tb.Th) of the extraction sockets and peri-implant bone. HE/Masson staining was used to detect the proliferation and distribution of bone cells, inflammatory cells, connective tissue, and collagen fibers in the extraction sockets and peri-implant bone. Immunohistochemical staining was used to detect the expression of peri-implant bone tissue-related proteins (ALP, COL-1, BMP-2, OPN, OCN, Runx2). Results Gross observation and Micro-CT examination revealed that the extraction sockets and peri-implant bone in the model group showed nonhealing wounds, exposed necrotic bone, and decreased bone healing indicators (BMD, BV/TV, Tb.N, Tb. Th), while the control group showed good bone healing (P<0.0001). HE/Masson staining showed that the extraction sockets and peri-implant bone in the model group had bone tissue necrosis, inflammatory cell infiltration, and dissolved bone cell nuclei with unclear structure. The control group showed good healing with abundant connective tissue and collagen fiber proliferation. Immunohistochemical staining showed that the expression of osteogenesis-related genes (ALP, COL-1, BMP-2, OPN) in the model group was downregulated (P<0.05). Conclusion This study established a BRONJ rat model that simulates the clinical drug administration environment and preliminarily verified the possible inhibitory effect of bisphosphonates on osseointegration and bone healing around implants.

     

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