RESUMO
BACKGROUND: MicroRNA-21 (miR-21) is a regulator of osteoclastogenesis and a promoter of osteoclast differentiation, but its role in periodontitis remains unclear. OBJECTIVE: To investigate whether miR-21 is involved in bone destruction in periodontitis. METHODS: Real-time PCR was used to detect and analyze the differential expression of miR-21 in periodontitis samples. Using liposome transfection method, miR-21 mimics (up-regulating miR-21) or miR-21 inhibitor (down-regulating miR-21) was used to transfect osteoclasts. Expressions of miR-21 and bone destruction markers TRAP and CTSK were detected by real-time PCR. Cell counting kit-8 was used to detect the miR-21 effect on osteoclast proliferation. RESULTS AND CONCLUSION: (1) MiR-21 expression increased in periodontitis samples. (2) When miR-21 mimics was transfected into osteoclasts, miR-21, TRAP and CTSK mRNA expression increased; when miR-21 inhibitor was transfected into osteoclasts, miR-21, TRAP and CTSK mRNA expression decreased. (3) Transfection with miR-21 mimics promoted the proliferation of osteoclasts, while transfection with miR-21 inhibitor inhibited the proliferation of osteoclasts. To conclude, miR-21 can be used as an important target for the treatment of periodontitis.