Preclinical in vivo research of magnesium-based implants for fracture treatment: A systematic review of animal model selection and study design

Background:Degradable magnesium implants are promising for clinical fracture treatment,providing less stress-shielding mechanical support and superior bone-strengthening benefits to traditional materials.The quality of preclinical research is essential for developing Mg implants;however,there are considerable variations in the model selection and study design in published studies,posing challenges for safe and effective clinical translation of lab discoveries.Objective:The purpose of this systematic review is to investigate the current progress on in vivo research of Mg implants for fracture treatment,focusing on model selection,Mg materials,implant design,methodological and analyzing techniques,aiming to provide comprehensive guidance for future preclinical research.Materials and methods:Pub Med and Embase online databases were searched to identify researches investigating Mg implants in animal models of fracture from 1960 to December 2019,using a combination of keywords:magnesium and fracture.Eligible studies were included without language restriction.Data extraction was conducted for qualitative analysis.Meta-analysis was not performed due to extensive heterogeneities among studies.Results:Twenty studies published from 2014 to 2019 were included.Publication information,animal model,methodological quality,implants preparation,and evaluation techniques were extracted.The methodological assessment revealed low to high risk of bias among studies.Both rodent and non-rodent species were selected,and the anatomical sites for inducing fractures included both cranial-facial and limb bones.Pure Mg and alloys with or without surface modification were evaluated,covering implant designs of both intra-medullary and extra-medullary fixation.Radiological and histological evaluations were commonly conducted.Conclusions:Published in vivo evidence confirmed the role of Mg-based implants in promoting fracture healing.However,considering heterogeneity in animal selection,implant preparation,and evaluation methods,there still lacks a standardized reference model.By analyzing the information extracted from included studies,the systematic review may facilitate planning and conducting preclinical research with translational perspective.

Animal models for testing biomaterials in periodontal regeneration

Periodontitis is a prevalent oral disease. It can cause tooth loss and has a significant impact on patients’ quality of life. While existing treatments can only slow the progression of periodontitis, they are unable to achieve complete regeneration and functional reconstruction of periodontal tissues. As a result, regenerative therapies based on biomaterials have become a focal point of research in the field of periodontology. Despite numerous studies reporting the superiority of new materials in periodontal regeneration, limited progress has been made in translating these findings into clinical practice. This may be due to the lack of appropriate animal models to simulate the tissue defects caused by human periodontitis. This review aims to provide an overview of established animal models for periodontal regeneration, examine their advantages and limitations, and outline the steps for model construction. The objective is to determine the most relevant animal models for periodontal regeneration based on the hypothesis and expected outcomes.

组织工程技术在阴道重建中的应用及进展

阴道缺损对患者造成的身心压力巨大,传统的阴道重建方法能在一定程度上恢复生理功能,但往往伴随着长治疗周期和多种并发症。随着组织工程技术的进步,其在阴道重建领域的应用展现出了解决女性生殖系统缺损的优势和潜能。本文分析了近年来组织工程在阴道重建领域的研究进展,探究种子细胞、生物材料、信号因子和动物模型的应用前景,以期为临床阴道修复提供启发和参考。

光生物调节诱导间充质干细胞的成骨分化

背景:间充质干细胞是从多种组织中分离出来的多能基质细胞,能够在特定的条件下分化为成骨细胞,光生物调节作为一种外部刺激能够单独或与其他诱导物联合使用加速间充质干细胞成骨分化的进程,从而为解决系列骨疾病提供新的思路。目的:综述光生物调节诱导间充质干细胞成骨分化的相关研究及机制,旨在为选用间充质干细胞作为种子细胞的骨组织工程奠定理论基础,并提出一些发展方向的建议。方法:检索中国知网、PubMed及Wed of Science数据库近年来发表的相关文献,中文检索词为“光生物调节,低功率激光,低水平激光,发光二极管,间充质干细胞,成骨分化,生物材料”;英文检索词为“Photobiomodulation,low level laser(light),light-emitting diode(LED),mesenchymal stem cell,osteogenic differentiation,Biomaterials”,最终纳入88篇文献进行分析。结果与结论:①以低水平激光和发光二极管为代表的光生物调节对于促进间充质干细胞的增殖与分化有着积极的影响。②光生物调节诱导间充质干细胞成骨分化的可行性已在细胞实验、动物实验中得到验证,一方面,光生物调节能够通过激活相关信号通路、上调成骨标志物的表达促进干细胞在体外扩增与分化;另一方面,光生物调节可以提高系统移植的干细胞体内存活率及归巢效应,缩短骨缺损愈合时间。但是光生物调节存在双相剂量效应,各项研究中激光参数、实验环境及细胞类型等要素参差不齐,使得研究结果缺乏一致性,难以推广。③光生物调节可以与生物材料、其他物理因子及药物联合使用加速干细胞成骨分化的进程。④总之,光生物调节因其无创、高效且无明显副反应等优势在医疗领域的应用逐渐广泛;近年来,其在骨组织工程中的作用也逐渐凸显,为骨缺损等疾病的治疗提供了新策略,后续研究应进一步探索光生物调节的标准化治疗参数。

Regulatory considerations for animal studies of biomaterial products

Animal studies play a vital role in validating the concept,feasibility,safety,performance and efficacy of biomaterials products during their bench-to-clinic translation.This article aims to share regulatory considerations for animal studies of biomaterial products.After briefly emphasizing the importance of animal studies,issues of animal studies during biomaterial products’translation are discussed.Animal studies with unclear purposes,flawed design and poor reporting quality could significantly reduce the translation efficiency and create regulatory challenges.Regulatory perspectives on the purpose,principle,quality and regulatory science of animal studies are also presented.Animal studies should have clear purposes,follow principles of 3R+DQ(replacement,reduction,refinement,design and quality)and execute under an efficiently operating quality management system.With the advancement of regulatory science,National Medical Products Administration of China has been developing a series of standards and guidance documents on animal studies of medical devices.Case studies of making decisions on whether to conduct animal studies are provided in the end with drug-eluting stents as examples.In summary,animal studies of biomaterial products should pay close attention to the rationale,design and quality in order to achieve their purposes.

Proper animal experimental designs for preclinical research of biomaterials for intervertebral disc regeneration

Low back pain is a vital musculoskeletal disease that impairs life quality,leads to disability and imposes heavy economic burden on the society,while it is greatly attributed to intervertebral disc degeneration(IDD).However,the existing treatments,such as medicines,chiropractic adjustments and surgery,cannot achieve ideal disc regeneration.Therefore,advanced bioactive therapies are implemented,including stem cells delivery,bioreagents administration,and implantation of biomaterials etc.Among these researches,few reported unsatisfying regenerative outcomes.However,these advanced therapies have barely achieved successful clinical translation.The main reason for the inconsistency between satisfying preclinical results and poor clinical translation may largely rely on the animal models that cannot actually simulate the human disc degeneration.The inappropriate animal model also leads to difficulties in comparing the efficacies among biomaterials in different reaches.Therefore,animal models that better simulate the clinical charateristics of human IDD should be acknowledged.In addition,in vivo regenerative outcomes should be carefully evaluated to obtain robust results.Nevertheless,many researches neglect certain critical characteristics,such as adhesive properties for biomaterials blocking annulus fibrosus defects and hyperalgesia that is closely related to the clinical manifestations,e.g,low back pain.Herein,in this review,we summarized the animal models established for IDD,and highlighted the proper models and parameters that may result in acknowledged IDD models.Then,we discussed the existing biomaterials for disc regeneration and the characteristics that should be considered for regenerating different parts of discs.Finally,well-established assays and parameters for in vivo disc regeneration are explored.

Advances and perspective on animal models and hydrogel biomaterials for diabetic wound healing

Diabetic wounds are a common complication in diabetes patients.Due to peripheral nerve damage and vascular dysfunction,diabetic wounds are prone to progress to local ulcers,wound gangrene and even to require amputation,bringing huge psychological and economic burdens to patients.However,the current treatment methods for diabetic wounds mainly include wound accessories,negative pressure drainage,skin grafting and surgery;there is still no ideal treatment to promote diabetic wound healing at present.Appropriate animal models can simulate the physiological mechanism of diabetic wounds,providing a basis for translational research in treating diabetic wound healing.Although there are no animal models that can fully mimic the pathophysiological mechanisms of diabetic wounds in humans,it is vital to explore animal simulation models used in basic research and preclinical studies of diabetic wounds.In addition,hydrogel materials are regarded as a promising treatment for diabetic wounds because of their good antimicrobial activity,biocompatibility,biodegradation and appropriate mechanical properties.Herein,we review and discuss the different animal models used to investigate the pathological mechanisms of diabetic wounds.We further discuss the promising future application of hydrogel biomaterials in diabetic wound healing.

Osteoarthritis animal models for biomaterial-assisted osteochondral regeneration

Clinical therapeutics for the regeneration of osteochondral defects(OCD)in the early stages of osteoarthritis remain an enormous challenge in orthopaedics.For in-depth studies of tissue engineering and regenerative medicine in terms of OCD treatment,the utility of an optimal OCD animal model is crucial for assessing the effects of implanted biomaterials on the repair of damaged osteochondral tissues.Currently,the most frequently used in vivo animal models for OCD regeneration include mice,rats,rabbits,dogs,pigs,goats,sheep,horses and nonhuman primates.However,there is no single“gold standard”animal model to accurately recapitulate human disease in all aspects,thus understanding the benefits and limitations of each animal model is critical for selecting the most suitable one.In this review,we aim to elaborate the complex pathological changes in osteoarthritic joints and to summarise the advantages and limitations of OCD animal models utilised for biomaterial testing along with the methodology of outcome assessment.Furthermore,we review the surgical procedures of OCD creation in different species,and the novel biomaterials that promote OCD regeneration.Above all,it provides a significant reference for selection of an appropriate animal model for use in preclinical in vivo studies of biomaterial-assisted osteochondral regeneration in osteoarthritic joints.

部分脱矿牙本质颗粒在上颌窦提升中的成骨性能

背景:研究证实牙本质颗粒具有良好的成骨潜能,其中未脱矿牙本质颗粒的空间维持作用好,但降解吸收缓慢,延缓了新骨生成速度;完全脱矿牙本质颗粒降解快,但支架作用不佳、新骨生成量有限。目的:评价部分脱矿牙本质颗粒作为骨移植材料的组织反应与成骨效果。方法:收集临床上拔除的废弃牙齿,去除牙釉质、牙骨质和牙髓,保留健康的牙本质,经过粉碎、筛选、煮沸、灭菌等处理制成直径0.5-1.0 mm的未脱矿牙本质颗粒;将牙本质颗粒先浸泡在2%硝酸中脱矿10 min,制成部分脱矿牙本质颗粒。取5只比格犬进行双侧上颌窦开窗提升骨缺损造模,随机分为2组,实验组植入部分脱矿异种牙本质颗粒,对照组植入未脱矿异种牙本质颗粒,术后3个月对植骨区进行大体观察、影像学检查和组织学测量分析。结果与结论:①大体观察:两组植骨区愈合良好,无炎症反应,实验组植骨区表面较平坦,可见少量残留牙本质颗粒包埋在骨基质中;对照组植骨区表面不平整,可见较多牙本质颗粒;②锥形束CT检查:实验组植骨区为低密度的阻射影,牙本质颗粒与周围组织边界不清,移植的牙本质颗粒总体积减小,牙本质颗粒间影像密度较高;对照组可见高密度的牙本质颗粒阻射影,与周围组织边界较明显,牙本质颗粒吸收程度较实验组轻;③组织学观察:两组植骨区均未见明显的炎症细胞浸润,实验组牙本质颗粒呈虫蚀状吸收,周围有新生骨组织围绕,新生编织骨较致密;对照组牙本质颗粒吸收程度较实验组轻,新骨生成率低于实验组(P<0.05);④结果表明:两种牙本质颗粒均可以诱导新骨形成,在相同时间内,部分脱矿牙本质颗粒的成骨效果优于未脱矿牙本质颗粒。

镁合金生物材料降解对内皮化细胞的影响

背景:镁合金材料依靠其优良的生物相容性和可降解性被誉为“革命性的金属材料”,其降解对内皮化的影响具有重大研究意义。目的:综述镁合金材料的研究进展。方法:利用计算机检索PubMed、中国知网数据库、Web of Science和Elsevier等数据库中的相关文献,以“金属生物材料,镁合金材料,血管支架,内皮化,动物实验,体外实验”为中文主题检索词,以“Metallic biomaterials,Magnesium alloys,Vascular stents,Endothelialization,Animal experiments,In vitro”为英文检索词进行检索,检索时限为2015-2022年,通过阅读文题和摘要进行初步筛选,最终纳入116篇文献进行结果分析。结果与结论:镁合金材料降解形成的含一定浓度镁离子的微环境有利于内皮细胞及平滑肌细胞的增殖,镁离子对内皮化的作用基本被认可。但降解速率过快是镁合金的最大问题,镁离子浓度过高会出现细胞毒性,因此目前的研究多集中于改善其降解,提高生物相容性。目前常见的改善镁合金降解的方法有纯化、合金化、表面改性,均可提高其耐腐蚀性,并且不同元素的合金化对镁合金的改善是不同方面,未来可能针对不同需求来选择不同合金化的镁合金以适应临床患者的情况,除引入其他元素外,改进镁合金的制作工艺改善降解问题也可能是一种值得尝试的方法。

新型血管内支撑物材料的药理学、毒理学实验

目的 研究新型血管内支撑物材料对实验动物循环、呼吸、自主活动、血管刺激的影响 .方法 利用不同剂量的血管内支撑物材料及其溶液刺激 SD大鼠、昆明种小鼠、家兔等动物 ,并进行相关的药理学、毒理学实验 .结果 内置新型血管内支撑物材料对大鼠心血管及呼吸系统无明显影响 ,血管内支撑物溶液静脉注射对大鼠平均动脉压、收缩压、舒张压、呼吸频率均无明显影响 .血管内支撑物溶液静脉注射对小鼠无明显兴奋或抑制作用 ;血管内注射支撑物溶液或血管内置支撑物 ,对家兔血管无明显刺激 ;家兔肠系膜动脉内置血管内支撑物后 ,血管内膜、中膜和外膜均未见明显病理变化 .结论 新型血管内支撑物材料对实验动物循环、呼吸、自主活动、血管无明显作用 。

动物胶原蛋白的应用研究进展

动物胶原蛋白是天然高分子生物材料,具有良好的生物相容性、无毒无害、可降解和独特的理化性能等优点。介绍了动物胶原蛋白的结构特点,并综述了其在铸造胶粘剂、皮革工业、造纸业、食品、生物医学及临床等领域中的应用。最后对动物胶原蛋白的发展方向进行了展望。

自硬性玻璃基生物骨水泥的实验研究

介绍了自硬性玻璃基生物骨水泥的制备、性质和应用．对所制得的骨水泥材料进行了初步动物试验，将骨水泥在生理盐水中沥出的浸出液注入ＩＣＲ小鼠腹腔内，观察其病理、体内血象、体重变化以及死亡情况．结果表明，此类骨水泥无急性毒性和长期毒性．将骨水泥填充于骨肿瘤刮除后的患者肱骨骨腔中，无任何异常反应并恢复了手臂功能，证实此材料可用作为骨填充材料．

胶原蛋白基再生医疗产品质量控制

由于胶原蛋白具有良好的生物相容性、可降解性、生物活性及可加工性等,作为再生医疗产品中重要的生物材料,被广泛应用于神经、骨、软骨、肌腱、韧带、血管植入物和皮肤修复中。为了保证胶原蛋白基再生医疗产品的安全和有效,有必要建立适当的质量控制体系。本文重点从原材料、产品性能、病毒去除/灭活、包装和灭菌等方面来探讨胶原蛋白基再生医疗产品质量控制的考虑要点,为该类产品的研发、生产及监管提供技术参考。

壳聚糖静电纺丝膜对兔球结膜损伤的促修复作用

目的评价壳聚糖/明胶静电纺丝膜对球结膜损伤后组织的促修复作用及抗瘢痕化作用。方法利用静电纺丝技术制备壳聚糖/明胶静电纺丝膜，采用钨灯丝扫描电子显微镜观察静电纺丝膜纤维表征。采用随机数字表法将30只新西兰白兔随机分为模型组、羊膜修复组和静电纺丝膜修复组，每组10只。各组实验兔右眼均接受手术切除6 mm×8 mm的球结膜，用弱酸灼伤损伤部位和角膜缘，制备兔球结膜损伤动物模型，羊膜修复组和静电纺丝膜修复组均于术中在伤口处结膜与巩膜之间平铺生物膜。分别于术后4、8、14、28 d行裂隙灯显微镜检查，观察兔眼手术伤口炎症反应及球结膜修复情况。结果扫描电子显微镜下可见静电纺丝膜纤维呈立体网状结构，与生物羊膜空间结构相似，纺丝直径均匀，为0.1～0.5 μm。裂隙灯显微镜下观察发现，术后4 d各组兔实验眼均未见明显炎症反应；术后8 d模型组兔眼球结膜水肿、糜烂，黏性分泌物较多，羊膜修复组和静电纺丝膜修复组兔球结膜轻度充血；术后14 d模型组兔球结膜水肿、充血，羊膜修复组和静电纺丝膜修复组兔球结膜均未见炎症反应；术后28 d模型组兔球结膜可见新生血管，羊膜修复组和静电纺丝膜修复组兔球结膜完全修复。组织病理学观察结果显示，模型组兔眼在术后4 d时伤口处球结膜组织游离，术后8 d球结膜根部贴附巩膜，术后14 d球结膜组织增厚，术后28 d大量纤维组织填充伤口，结膜上皮化。羊膜修复组兔眼术后4 d羊膜贴附于巩膜与球结膜之间，术后8 d羊膜开始消融，术后14 d纤维组织生长且球结膜上皮化，术后28 d球结膜组织修复，瘢痕组织填充较少。术后4 d静电纺丝膜修复组可见静电纺丝膜孵育于结膜与巩膜之间，静电纺丝膜消融，术后8 d球结膜上皮沿巩膜长入损伤部位，术后14 d结膜下组织生长，术后28 d结膜完全修复。结论与单纯球结膜损伤缝合相比，羊膜或壳聚糖/明胶静电纺丝膜修补对损伤的球结膜有促进修复的作用，且可减轻组织瘢痕化，壳聚糖/明胶静电纺丝膜的促组织修复作用优于羊膜。

动物皮在生物医学材料中的应用

对动物皮本体及其水解产物皮胶原、明胶、水溶性明胶及多肽在生物医学材料各个方面的应用进行了综述。重点介绍皮胶原在止血方面、药物释放载体材料、组织工程、美容矫形方面的应用,并指出利用动物皮制造生物医学材料具有广阔的发展前景。

骨缺损动物模型的研究进展

骨缺损达到一定范围及距离后,机体自身无法自行修复,即临界骨缺损,需自体骨移植、异体骨移植或骨组织工程进行修复。骨缺损动物模型常被用以评估骨组织工程中骨替代生物材料的再生能力。本文概述了近年来常用的动物骨缺损模型和目前可应用的研究方向,并阐述了口腔相关动物骨缺损模型的现状。

镁合金生物材料动物体内实验的研究热点

背景:作为新一代可降解生物材料,镁合金具有良好的力学性能、生物相容性及可降解性能,是当前生物材料学领域的研究热点之一。目的:综述近年来镁合金生物材料动物体内实验研究的现状及问题。方法:利用计算机检索PubMed及中国知网数据库中的相关文献,以"金属生物材料、可降解金属、镁合金材料、镁基植入物、血管支架、动物实验、腐蚀速率、生物安全性"为中文检索词,以"Metal biomaterials,degradable metals,magnesium alloy materials,magnesium-based implants,vascular stents,animal experiment,corrosion rate,biosafety"为英文检索词进行检索,检索时限为2016年1月至2021年6月,通过阅读文题和摘要进行初步筛选,最终纳入70篇文献进行结果分析。结果与结论:(1)镁合金的安全性和降解速率是其能否作为可降解生物医用材料应用于临床的主要影响因素。(2)镁合金在骨折的内固定、骨肿瘤术后骨缺损的修复、韧带固定及冠状动脉狭窄中作为血管支架等方面的应用具有巨大潜力,镁合金具有优良的组织相容性,短期应用无安全性隐患,但尚缺乏长期生物安全性的研究结果。(3)镁合金血管支架在血管病变部位前期可起支撑血管作用,待该部位血管恢复正常功能后,支架被机体吸收和代谢,待血管再次发生狭窄和阻塞等病变时可再次植入镁合金支架,达到重复修复的目的。(4)当前镁合金已成为医疗器械研究领域的热点材料,但目前的研究结果仅是在动物实验或小样本临床试验中获得。(5)目前研究者们已基本达成共识,镁合金的合金化、表面处理和复合材料的制备等方法已可有效解决其安全性问题和降解速率过快的缺陷,但既往研究显示在镁合金实验中关于动物选择、植入物制备和评价方法等方面还缺少标准化的参考标准。(6)因此,在未来完善和制定镁合金实验的相关参考标准,对制定严谨和良好的临床前研究十分必要,这也将为镁合金材料的有效性和安全性评估提供有力的理论支撑。

Multiphasic scaffolds for the repair of osteochondral defects:Outcomes of preclinical studies

Osteochondral defects are caused by injury to both the articular cartilage and subchondral bone within skeletal joints. They can lead to irreversible joint damage and increase the risk of progression to osteoarthritis. Current treatments for osteochondral injuries are not curative and only target symptoms, highlighting the need for a tissue engineering solution. Scaffold-based approaches can be used to assist osteochondral tissue regeneration, where biomaterials tailored to the properties of cartilage and bone are used to restore the defect and minimise the risk of further joint degeneration. This review captures original research studies published since 2015, on multiphasic scaffolds used to treat osteochondral defects in animal models. These studies used an extensive range of biomaterials for scaffold fabrication, consisting mainly of natural and synthetic polymers. Different methods were used to create multiphasic scaffold designs, including by integrating or fabricating multiple layers, creating gradients, or through the addition of factors such as minerals, growth factors, and cells. The studies used a variety of animals to model osteochondral defects, where rabbits were the most commonly chosen and the vast majority of studies reported small rather than large animal models. The few available clinical studies reporting cell-free scaffolds have shown promising early-stage results in osteochondral repair, but long-term follow-up is necessary to demonstrate consistency in defect restoration. Overall, preclinical studies of multiphasic scaffolds show favourable results in simultaneously regenerating cartilage and bone in animal models of osteochondral defects, suggesting that biomaterials-based tissue engineering strategies may be a promising solution.

动物源性生物材料体外淋巴细胞增殖试验方法的建立

目的:建立可用于评价动物源性生物材料细胞免疫的体外淋巴细胞增殖试验方法。方法:采用C57小鼠脾脏淋巴细胞,通过淋巴细胞数量、阳性对照剂(刀豆蛋白A,Con A)浓度和培养时间等条件筛选,用CCK8试剂检测细胞增殖率,初步优化体外淋巴细胞增殖试验方法。采用牛心包组织(原材料)的浸提液和匀浆液,作为抗原特异性的阳性对照组考察样品前处理方式对试验体系的影响,并用流式细胞仪分析增殖后的淋巴细胞亚型百分比,考察样品制备方式对淋巴细胞亚型增殖影响的差异。结果:本试验中小鼠脾淋巴细胞体外增殖试验条件确定为每孔接种6×105个淋巴细胞,阳性对照孔Con A浓度为2.5μg·mL-1,培养时间为3 d。牛心包浸提液和匀浆液的淋巴细胞增殖率均约为细胞对照组的2倍,两者的淋巴细胞亚型百分比变化不同于Con A组,未出现T细胞、CD4 T细胞、CD8 T细胞百分比的增加。浸提液组与匀浆液组的活化NK细胞和NKT细胞百分比与对照组相比均明显升高,但浸提液组的升高幅度数倍高于匀浆液组,且仅浸提液组NK细胞百分比与对照相比出现了明显倍增。结论:本研究建立了以动物组织(原材料)为抗原特异性阳性对照的体外淋巴细胞增殖试验方法。动物组织(原材料)浸提和匀浆样品均可以产生淋巴细胞增殖阳性结果,其促进淋巴细胞增殖的机理(亚型分类)不同于Con A等有丝分裂原,提示使用作为动物组织(原材料)阳性对照更能反映试验体系的敏感性。