Bone tissue engineering (BTE) is a rapidly developing strategy for repairing critical-sized bone defects to address the unmet need for bone augmentation and skeletal repair. Effective therapies for bone regeneration primarily require the coordinated combination of innovative scaffolds, seed cells, and biological factors. However, current techniques in bone tissue engineering have not yet reached valid translation into clinical applications because of several limitations, such as weaker osteogenic differentiation, inadequate vascularization of scaffolds, and inefficient growth factor delivery. Therefore, further standardized protocols and innovative measures are required to overcome these shortcomings and facilitate the clinical application of these techniques to enhance bone regeneration. Given the deficiency of comprehensive studies in the development in BTE, our review systematically introduces the new types of biomimetic and bifunctional scaffolds. We describe the cell sources, biology of seed cells, growth factors, vascular development, and the interactions of relevant molecules. Furthermore, we discuss the challenges and perspectives that may propel the direction of future clinical delivery in bone regeneration.
目的使用Micro-CT,探讨重组人甲状旁腺激素(rh PTH)在2月龄雄性大鼠骨折愈合过程中的作用。方法应用2月龄雄性SD大鼠建立单侧闭合性股骨骨折内固定模型,随机分为甲状旁腺素治疗组和对照组,术后分别皮下注射重组人甲状旁腺素(1-34)10μg/(kg.d)或等剂量生理盐水安慰剂(对照组),分别于术后第2、7、14、21和42天取双侧股骨标本,分别行X线检查和Micro-CT观察,并进行骨结构的定量分析。结果术后第21天,甲状旁腺素组骨折断端两侧的骨痂之间连续性良好,骨折线已模糊不清。甲状旁腺组较对照组,在术后第42天骨体积(bone Volume,BV)、骨体积分数(BV/TV)、骨密度(bone mineral density,BMD)和骨小梁模式因子(trabecular bone pattern factor,Tb.Pf)明显高于对照组;而骨小梁分离度(trabecular separation,Tb.Sp)和各向异性的程度(degree of anisotropy,DA)低于对照组。结论低剂量重组人甲状旁腺激素可提高大鼠骨折BV、BV/TV、Tb.Pf和BMD而降低Tb.Sp和DA,从而促进骨折的愈合。
