RESUMO
BACKGROUND:The repair and clinical outcome of bone defects remains a hot and difficult area of clinical research,which is a common problem that plagues clinicians.Constructing suitable,reproducible and infinitely close to clinical animal experimental models and their scientific evaluation are essential for further clinical treatment of related diseases. OBJECTIVE:To retrospectively analyze the preparation methods and characteristics of common animal models of femoral bone defects and to assess their strengths and weaknesses,thereby providing some reference for relevant researchers to select appropriate animal models of femoral bone defects. METHODS:PubMed,Web of Science,Medline,and CNKI were retrieved for relevant literature published from January 1,2000 to August 1,2022.The keywords were"bone defect,bone,bones,defect,defects,defective,animal model,animal,model,laboratory,laboratory animal,animal laboratory"in English and"bone defect,animal model,experiment"in Chinese. RESULTS AND CONCLUSION:Twenty-seven randomized controlled animal experiments involving rats,mice,New Zealand rabbits,and sheep were included,analyzed and assessed.The most common types of bone defects were cylindrical bone defects and segmental osteotomy bone defects,generally found in the middle and distal femur.These models are mostly used to evaluate the effects of bone repair materials,drugs,drug-loaded active substances and physical therapy on bone defect repair and explore defect healing mechanisms,particularly the weight-bearing bone defect repair mechanism.Different defect kinds and femoral bone defect ranges have been found in different animal experiments.Researchers can select the suitable animal model and bone defect type based on the goal of the experiment and then set an acceptable bone defect value.Current studies have shown that cylindrical and segmental osteotomy-induced bone defects,mainly in the distal and middle femur,are mostly used in the animal models of femoral bone defects and that the surgical methods and postoperative management are more mature and operable to provide mature experimental animal models.In terms of cylindrical bone defects,rats and New Zealand rabbits are more suitable,whereas segmental osteotomy has no special requirements and all types of animals can meet the experimental requirements.
RESUMO
BACKGROUND:Heterotopic ossification is a dynamic growth process.Diverse heterotopic ossification subtypes have diverse etiologies or induction factors,but they exhibit a similar clinical process in the intermediate and later phases of the disease.Acquired heterotopic ossification produced by trauma and other circumstances has a high incidence. OBJECTIVE:To summarize the molecular biological mechanisms linked to the occurrence and progression of acquired heterotopic ossification in recent years. METHODS:The keywords"molecular biology,heterotopic ossification,mechanisms"were searched in CNKI,Wanfang,PubMed,Embase,Web of Science,and Google Scholar databases for articles published from January 2016 to August 2022.Supplementary searches were conducted based on the obtained articles.After the collected literature was screened,131 articles were finally included and summarized. RESULTS AND CONCLUSION:(1)The occurrence and development of acquired heterotopic ossification is a dynamic process with certain concealment,making diagnosis and treatment of the disease difficult.(2)By reviewing relevant literature,it was found that acquired heterotopic ossification involves signaling pathways such as bone morphogenetic protein,transforming growth factor-β,Hedgehog,Wnt,and mTOR,as well as core factors such as Runx-2,vascular endothelial growth factor,hypoxia-inducing factor,fibroblast growth factor,and Sox9.The core mechanism may be the interaction between different signaling pathways,affecting the body's osteoblast precursor cells,osteoblast microenvironment,and related cytokines,thereby affecting the body's bone metabolism and leading to the occurrence of acquired heterotopic ossification.(3)In the future,it is possible to take the heterotopic ossification-related single-cell osteogenic homeostasis as the research direction,take the osteoblast precursor cells-osteogenic microenvironment-signaling pathways and cytokines as the research elements,explore the characteristics of each element under different temporal and spatial conditions,compare the similarities and differences of the osteogenic homeostasis of different types and individuals,observe the regulatory mechanism of the molecular signaling network of heterotopic ossification from a holistic perspective.It is beneficial to the exploration of new methods for the future clinical prevention and treatment of heterotopic ossification.(4)Meanwhile,the treatment methods represented by traditional Chinese medicine and targeted therapy have become research hotspots in recent years.How to link traditional Chinese medicine with the osteogenic homeostasis in the body and combine it with targeted therapy is also one of the future research directions.(5)At present,the research on acquired heterotopic ossification is still limited to basic experimental research and the clinical prevention and treatment methods still have defects such as uncertain efficacy and obvious side effects.The safety and effectiveness of relevant targeted prevention and treatment drugs in clinical application still need to be verified.Future research should focus on clinical prevention and treatment based on basic experimental research combined with the mechanism of occurrence and development.