Mechanism underlying the anti-diabetic potential of bee venom as compared to bone marrow mesenchymal stem cells in the diabetic rat tongue.

Abstract

Diabetes mellitus (DM) is a critical chronic metabolic disease. Several treatment modalities are currently under investigation. Both bee venom (BV) and bone marrow mesenchymal stem cells (BMSCs) can possibly offer an approach for treating type I diabetes. The aim of the present study was to investigate the mechanism underlying the anti-diabetic effect of BV as compared to BMSCs on the tongue mucosa of diabetic rats. A total of 52 male albino rats were used in the current study. The rats were randomly assigned into 4 groups: group 1 (control); group 2 (streptozocin (STZ)); group 3 (BV-treated); and group 4 (BMSC-treated). Diabetes mellitus was induced via an intraperitoneal (IP) injection of STZ in the rats from groups 2, 3 and 4. Following the diagnosis of DM, the rats in group 3 were injected with a daily dose of 0.5 mg/kg of BV, while the rats in group 4 were treated with a single injection of BMSCs. All rats were euthanized after 4 weeks, and their tongues were dissected and divided into halves. The right halves of the tongues were utilized for the histological examination, followed by morphometric analysis. In contrast, the left halves were used to detect the local gene expression of transforming growth factor beta 1 (TGF-β1) and vascular endothelial growth factor (VEGF). Group 2 revealed marked disruption in the morphology of the fungiform and filiform papillae, and atrophic epithelial changes in both dorsal and ventral surface epithelium as compared to other groups. Group 4 showed a significantly larger number of taste buds, and a higher gene expression of TGF-β1 and VEGF as compared to groups 2 and 3. Additionally, BV and BMSCs effectively increased the thickness of dorsal and ventral surface epithelium as compared to group 2. Treatment with BMSCs was associated with significant improvement in the morphology and number of lingual epithelial cells and taste buds in the tongues of diabetic rats as compared to BV-treated rats, which was due to the local upregulation of TGF-β1 and VEGF gene expression.