Abstract
Certain microRNAs (miRs) have important roles in the maintenance of bone development and metabolism, and a variety of miRs are known to be deregulated in diabetes. The present study investigated the role of miR‑203‑3p in the regulation of bone loss by assessing jaw bones of a rat model of type 2 diabetes. The results indicated that miR‑203‑3p inhibited osteogenesis in the jaws of diabetic rats and in rat bone marrow mesenchymal stem cells cultured in high‑glucose medium. A luciferase re-porter assay was used to verify the bioinformatics prediction that miR‑203‑3p targets the 3'‑untranslated region of Smad1, which is an important mediator of the bone morphogenetic protein (BMP)/Smad pathway. Overexpression of Smad1 attenuated the miR‑203‑3p‑mediated suppres-sion of osteogenic differentiation. It was therefore indicated that the BMP/Smad pathway is attenuated and the transforming growth factor‑β/activin pathway is promoted by Smad1 reduction. Taken together, it was indicated that miR‑203‑3p inhibits osteogenesis in jaw bones of diabetic rats by targeting Smad1 to inhibit the BMP/Smad pathway.