Increased mast cell number is associated with a decrease in beta-cell mass and regeneration in type 2 diabetic rats

•Mast cell count is significantly increased in endocrine pancreas of T2D.•Mast cell count is negatively correlated with the islet mass, β-cell mass, and % of β-cells per islet.•Mast cell count is negatively correlated with β-cell proliferation and neogenesis frequency.•Mast cell count is positively correlated with the % of glucagon cells per islet. The role of mast cells (MCs) in type 2 diabetes (T2D) is not thoroughly studied as much as in T1D. Therefore in the current study we investigated correlation between these cells and various parameters of islets of Langerhans (IOL) in rats which were equally divided (n = 40) into; control and diabetic groups. We detected a significantly increased (p