Explore the effects of oxidative stress on the glucagon like peptide-1/dipeptidyl peptidase-4 (GLP-1/DPP-4) signaling pathway and inflammatory factor indicators in 3T3-L1 preadipocytes.

3T3-L1 preadipocytes were subcultured and divided into a blank Control group and an endoplasmic reticulum stress inducer Tunicamycin (TM) group. Cells were induced to differentiate in a six well plate. After the cell density in the well plate reaches 80%-90% and the cells differentiate and mature, co culture the cells with 5 ug/mL TM for 24 hours; Subsequently, total RNA and protein were extracted, and their concentrations were measured and analyzed using RT-PCR and WB assays for oxidative stress indicators such as NADPH oxidase 4 (Nox-4), glucagon like peptide-1 (GLP-1), GLP-1 receptor (GLP-1R), dipeptidyl peptidase-4 (DPP-4), as well as inflammatory factors such as monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). The relative expression levels of mRNA and protein are determined.

After 24 hours of TM culture, the mRNA and protein expression levels of Nox-4 in 3T3-L1 adipocytes significantly increased (P<0.001). The mRNA and protein expression levels of GLP-1 and GLP-1R in TM group were significantly reduced (P<0.001); At the same time, the mRNA and protein expression levels of DPP-4 in the TM group significantly increased (P<0.001). TM significantly induces 3T3-L1 adipose inflammatory factor indicators such as MCP-1, IL-6, and TNF-α. The mRNA expression level of increased significantly compared to the Control group (P<0.001).

Oxidative stress induces abnormalities in the GLP-1/DPP4 pathway and promotes high expression of inflammatory factors in 3T3-L1 adipocytes, and the underlying mechanisms need further research.