The molecular mechanism study of insulin on proliferation and differentiation of osteoblasts under high glucose conditions.

To explore the molecular mechanism of insulin on proliferation and differentiation of MC3T3-E1 cell under high glucose conditions. We first investigated the effect of different concentrations of insulin on the osteoblast cell proliferation and cell differentiation at various time points by MTT analysis, cell cycle analysis, and expression detection of differentiation genes. Then, we used 200 ng/mL of insulin to treat the osteoblast cell at different time points for identifying the common differentially expressed mRNAs among various time points by RNA sequencing. Thirdly, we performed the gene ontology (GO) and the Kyoto Encyclopaedia of Genes and Genomes (KEGG) analysis to explore the biological function of these common differentially expressed mRNAs. The results showed that insulin promoted the cell proliferation and differentiation of osteoblast cell. In RNA sequencing, a total of 31 common differentially expressed mRNAs were identified between different time points. Mt1, Tmem135, Avp, and Dlg2 were found to be associated with the new bone formation. In addition, three important signalling pathways, namely, lysosome, glutamatergic synapse, and chemokine signalling pathways, were found in the KEGG enrichment analysis. Our work demonstrated that insulin could promote the osteoblast cell proliferation and cell differentiation, which may play a key role in bone formation. SIGNIFICANCE OF THE STUDY: Our result showed that insulin could promote the proliferation and differentiation of osteoblast at both cellular and molecular levels, which may promote the new bone formation in the osteoblasts.