中文摘要：

MicroRNA（miRNA）是一种非编码蛋白RNA，其长度约为22nt，广泛存在于真核生物细胞中，在生物的生长、发育和疾病发生等生物学过程中发挥着重要作用。随着对miRNA研究的不断深入，其在骨代谢方面的研究也逐渐展开。作为体内唯一一种负责骨吸收的细胞，破骨细胞（Oc）在机体骨组织生理及病理性过程中占有重要地位。OC的形成和分化受多种因素调节，研究发现多种miRNA对oC有着调控作用，如miR-21、miR-422a和miR-148a能够促进OC形成，miR-124、miR-155和miR-503则抑制OC形成，除此以外，某些miRNA还能通过OC调控肿瘤骨转移。对这些机制的研究将从另一个层面揭示代谢性骨病的病因，并对临床治疗提供指导。论文对miRNA在OC形成和分化过程中的作用及机制进行综述。

英文摘要：

MicroRNA,a class of noncoding RNA,has approximately 22 nucleotides and exists in eukaryotic cells widely.It is demonstrated that miRNAs play an important role in physiological prosesses of organism such as growth,development and occurrence of disease.With the deep research, how miRNAs affect bone metabolism is going tO be clear. As the unique cell responsible for bone resorption,osteoclast （OC） is an important participator in physiological and pathological processes of bone tissue.The formation and differ- entiation of osteoclast is regulated by multi factors, such as various miRNAs, miR-21, miR-422a and miR- 148a can promote the differentiation of OC, while miR-124, miR-155 and miR-503 suppress the formation of OC,some miRNAs can also mediate tumor bone metastasis via OC. Study of these mechanisms will reveal the causes of metabolic bone disease on another level and provide guidance for clinical treatments.This paper reviewed the functions and mechanisms of miRNAs in the formation and differentiation of osteo clasts.