The Abnormal Expression of Tubular SGLT2 and GULT2 in Diabetes Model Mice with Malocclusion-Induced Hyperglycemia

Background: A relationship between malocclusion and the promotion of diabetes has been suggested. In hyperglycemia, the expression of sodium-glucose cotransporter 2 (SGLT2) and the facilitative glucose transporter 2 (GLUT2) is upregulated in proximal tubular cells, leading to an increase in renal glucose reabsorption. The present study aimed to investigate whether malocclusion contributes to diabetic exacerbation. Methods: Streptozotocin (STZ)-induced diabetic mice with malocclusion due to cutting molars were investigated based on increased blood glucose levels. PCR and immunohistochemical analyses were performed on diabetic mice kidneys to investigate the expression of SGLT2 and GLUT2. Results: Animal experiments were performed using 32 mice for 21 days. The time to reach a diabetic condition in STZ-administered mice was shorter with malocclusion than without malocclusion. The increase and mean blood glucose levels in STZ-administered mice were steeper and higher with malocclusion than without malocclusion. Urea albumin, BUN, and CRE levels were higher in diabetic mice with malocclusion than in diabetic mice without. Immunoreaction with anti-SGLT2 and anti-GLUT2 in the renal tissue of STZ-administered mice was stronger with malocclusion than without malocclusion. The amounts of SGLT2 and GLUT2 mRNA in the renal tissue in STZ-administered mice were higher with malocclusion than without malocclusion. The amounts of TNF-a and IL-6 mRNA in the large intestinal tissue in STZ-administered mice were higher with malocclusion than without malocclusion. Conclusions: Our results indicate that malocclusion accelerates the tubular expression of SGLT2 and GLUT2 under hyperglycemia. Malocclusion may be a diabetes-exacerbating factor with increased poor glycemic control due to shortened occlusion time resulting from swallowing food without chewing.