Objective: In this study, it was aimed to evaluate the effect of cinnamon extract on TLR4 expression and numerical distribution of mast cells in experimental diabetic rat kidneys and examine the relationships between TLR4 and mast cells.

Materials and Methods: Thirty-two Wistar albino male rats were used in this study. Control group, Diabetes group, Cinnamon group and Diabetes + cinnamon group. After confirming the occurrence of diabetes in rats, cinnamon at a dose of 0.5 mg/kg was administered by oral gavage to animals in the cinnamon group and diabetes + cinnamon group for 14 days. During the experiment, no application was made to the rats in the control group.

Results: When the cinnamon group was evaluated, there was an increase in mast cells compared to the control group. At the same time, there was a significant decrease in the number of mast cells in the diabetes + cinnamon group compared to the diabetes group. An increase in the intensity of TLR4 expression was determined between the control and experimental groups. The highest TLR4 expression was found in the diabetic group as a remarkable finding in our study. It was determined that cinnamon extract reduced TLR4 immunoreactivity that was increased in the diabetes group in diabetes + cinnamon group.

Conclusion: It was determined that cinnamon increases mast cell number and expression of TLR4 in healthy rats. At the same time, it caused a synergistic decrease in increased mast cell and TLR4 expression in rats with diabetes.