Immunohistochemical Evidence of Pancreatic beta-cell Regeneration in streptozotocin-induced type 2 Diabetic Rats treated with Gymnema sylvestre Extract

The effective dose Gymnema sylvestre (GS) leaves methanolic extract (400 mg/kg) was administered orally to neonatally streptozotocin-induced non-obese type 2 diabetic rats for 28 days and fasting glucose, serum insulin and β-cell function were measured after the treatment periods. Pancreatic β- and α-cells were identified by immunohistochemistry and β-cells number was evaluated by morphometric analysis. GS extract showed antidiabetic activity through improving serum insulin and β-cell function. The β-cells number was increased significantly in the GS-treated diabetic rats. The immunohistochemal data revealed presence of few newly formed insulin positive β-cells in the GS-treated diabetic islets. This is the direct immunohistochemal evidence of β-cells regeneration and/ or neoformation in pancreatic islets by GS extract. Cluster of β-cells without any α-cells were appeared in GS-treated diabetic rats, not in STZ-induced diabetic control rats, suggesting β-cells regeneration in GS-treated pancreas rather than stem-cell induced growth.