Resistin Regulates The Nitric Oxide System In Juvenile Rat Aortic Endothelial Cells

Objective: Resistin, a novel adipocyte-derived cytokine, is closely associated with adult cardiovascular and cerebrovascular diseases. In this study, we have investigated the effects of mouse recombinant resistin on endothelial cell activation, Nitric Oxide (NO) production, the endothelial nitric oxide synthase (eNOS) protein, gene expression as well as eNOS phosphorylation regulation in Pet-rat Aortic Endothelial Cells (RAECs).Methods: RAECs were isolated from male SD rats (100-130 g) by the primary explant technique and characterized with endothelial-specific markers: rabbit polyclonal antibody against Factorâ…§-related antigen.Incubated RAECs with mouse recombinant resistin (10 to 100 ng/ML, 24 hours). The direct effects of resistin on RAEC viability was tested by MTT assay. NO production and NOS activity were detected by nitrate reductase method and chemistry colorimetric method. The eNOS and Phospho-eNOS (Ser1177) protein levels were determined by immunoblotting. The eNOS mRNA level was detected by reverse transcription polymerase chain reaction (RT-PCR).Results: Incubated RAECs with resistin (10 to 100 ng/ML) for 24 hours:1. Resistin significantly decreased the metabolic activity when used at 50 and 100ng/ml concentrations.2. Resistin did not affect NO production in RAECs at concentrations studied.3. No effects of resistin on TNOS(total NOS) , inducible NOS (iNOS) and TNOS-iNOS activity were observed. 4. Resistin can decrease eNOS protein when used at 50 and 100ng/ml concentrations.5. Resistin did not affect P-protein expression in RAECs at concentrations studied.6. Resisitn significantly decreased eNOS mRNA expression when used at 50 and 100ng/ml concentrations.Conclusions: The novel adipokine resistin exerts direct effects to decrease RAEC viability. Resistin can decrease eNOS protein and eNOS mRNA expression in RAEC without the changes of phosphorylation at Ser1177. Whereas, treatment with resistin has no effect on NO production and NOS activity in RAEC at concentrations studied.