Abstract:

Objective: To explore the mechanism of nuclear factor-kappa B (NF-κB), phosphatidylinositol 3-kinase (PI3K)/protein kinase B(PKB/Akt) and mitogen-activated protein kinase (MAPK) signaling pathways after intervention of advanced glycosylation end products (AGEs) in peripheral blood mononuclear cells (PBMCs) and osteoblasts (OB) in rats, so as to provide certain experimental basis and theoretical basis for further research on the clinical treatment of periodontal tissue inflammation caused by diabetes mellitus. Methods: AGEs were prepared, PBMCs and OB were isolated and cultured in vitro. CCK-8 was used to detect the cell viability intervened by different concentrations and time of AGEs. Western blot and qRT-PCR were used to detect the expression changes of genes related to NF-κB, PI3K/PKB and MAPK signaling pathways. Results: OB and PBMCs were successfully isolated and cultured in vitro. The activity of PBMCs and OB cells was significantly correlated with the concentration, time and interaction of AGEs. With the increase of AGEs concentration and time, the activity of PBMCs and OB cells significantly decreased (P<0.001). AGEs stimulation significantly increased the expression of NF-κB in PBMCs and the contents of tumor necrosis factor α(TNF-α), interleukin-1β(IL-1β) (P<0.01). TNF-α, IL-1β levels were significantly reduced after inhibition of NF-κB pathway (P<0.01). NF-κB p65, JNK, and p38 phosphorylated and non-phosphorylated proteins increased significantly after AGEs stimulation of OB (P<0.05). The phosphorylated protein expression of IκB was significantly increased, while the expression of non-phosphorylated protein was decreased (P<0.01).The expressions of NF-κB p65, JNK, and IκB were significantly increased at the mRNA levels, and the expressions of IκB mRNA were significantly decreased (P<0.05). There was no difference in the expression of Akt in either phosphorylated or non-phosphorylated proteins or at the mRNA level (P>0.05). With the addition of MAPK signaling pathway inhibitors, the phosphorylation and non-phosphorylated protein expressions of NF-κB p65, p38 and JNK were significantly reduced, and the phosphorylated protein of IκB was significantly decreased and the non-phosphorylated protein was significantly increased compared with the group with AGEs alone (P<0.05). The results of qRT-PCR showed that the expression of IκB increased significantly after the addition of the JNK pathway blocker (P<0.05), and the expression of NF-κB p65, p38 and JNK decreased, but the difference was not significant (P>0.05). While NF-κB p65, p38 and JNK were significantly decreased and IκB was significantly increased in the AGEs group after the addition of the p38 pathway blocker (P<0.05). At this time, there was still no significant change in the expression of Akt at the protein level and mRNA level (P>0.05). Conclusion: AGEs inhibit the proliferation of PBMCs and OB, and the NF-κB and MAPK pathways are likely involved in regulating this process, but not the PI3K/PKB pathway.

Key words: Glycation end products, advanced, Peripheral blood mononuclear cells, Osteoblasts, Signal transduction