Abstract: Objective:?To investigate the effect of inhibiting miR-145 on inflammatory response in experimental peri-implantitis in mice. Methods:?Forty male C57BL/6J mice were randomly divided into four groups: normal control group, peri-implantitis control group, peri-implantitis miR-NC group, and peri-implantitis miR-inhibitor group. All groups received dental implant insertion in maxillae, then the three peri-implantitis groups received ligation around implants to induce peri-implantitis. Afterwards, miR-145 inhibitor was injected into peri-implant gingiva in peri-implantitis miR-inhibitor group, and its negative control reagent was injected in peri-implantitis miR-NC group. Peri-implant bone loss in each group was detected using micro-computer tomography, and infiltration of inflammatory cells around the implants was examined using hematoxylin and eosin staining. Expression levels of miR-145, C-C motif chemokine ligand 2 (CCL2), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), interleukin 10 (IL-10) and matrix metalloproteinase 8 (MMP8) in peri-implant gingival tissues were detected using real-time quantitative PCR. Results:?Compared with normal control group, bone loss and inflammatory cell infiltration in all peri-implantitis groups were greater (P<0.05), and the expressions of inflammation-related factors CCL2, TNF-α, IL-1β, IL-10 and MMP8 were increased (P<0.05). Upon miR-145 inhibition, the bone loss and inflammatory cell infiltration were ameliorated, and the expression of inflammation-related factors CCL2, TNF-α, IL-1β and MMP8 was decreased, while the expression of IL-10 enhanced (P<0.05). Conclusions:?Inhibition of miR-145 expression could suppress peri-implantitis, which may be associated with the regulationof inflammation-related factor expression in peri-implant gingival tissues.