Abstract
OBJECTIVE: To investigate the potential mechanisms underlying the dark red tongue color formation induced by hyperglycemia. METHODS: A high-fat diet and intraperitoneal injection of streptozotocin were used to establish a diabetes model. The color and blood flow of tongues were analyzed by the Tongue Diagnosis Analysis System and laser Doppler flowmetry, respectively. Inflammatory factors and adhesion factors were measured in the circulation and tongue tissue by an enzyme-linked immunosorbent assay. Western blotting was employed to evaluate nuclear factor-kappa B (NF-κB) p50 and inhibitor of kappa B kinase protein expression levels in the tongue. Then, the NF-κB inhibitor, pyrrolidine dithiocarbamic acid ammonium salt was utilized to repress NF-κB pathway activation to validate that the NF-κB pathway plays a key role in blood flow and dark red tongue color formation. RESULTS: The diabetic rats displayed a dark red tongue color that was accompanied by NF-κB pathway activation and decreased blood flow in the tongue. These effects could be reversed by the NF-κB inhibitor. CONCLUSIONS: Our investigation demonstrated that hyperglycemia led to dark red tongue color formation by decreasing blood flow in the tongue, which was partly due to NF-κB pathway activation.