Mirtazapine suppresses sterile inflammation through NLRP3-inflammasome in diabetic rat kidney

Aim The aim of this study was to investigate the effects of mirtazapine, which is anti-oxidative and antidepressant agent, on the kidney damage caused by diabetes mellitus. Materials and methods: The rats were randomly divided into three groups (n = 7 animals in each group). The group I rats served as control and they received 0.1 mol/L of citric acid buffer (pH = 4.5) as vehicle. The rats in the group II (DM group) and III (DM + Mirtazapine-treated group) were treated intraperitoneally with a single dose of 55 mg/kg streptozotocin dissolved in 0.1 mol/L of citric acid buffer. Group DI rats were also received 20 mg/kg/day of mirtazapine for 2 weeks. At the end of the experiment, the rats were sacrificed. Then, the kidneys were excised and prepared for microscopical examination, caspase-1 and NLRP3 proteins were examined using immunohistochemistry and western blotting. The TUNEL assay for apoptosis and ELLSA assay for IL-1 beta were performed. Results: Histological examination showed that mirtazapine administration has an ameliorative effect on DM-induced kidney damage. Immunohistochemical and western blot analyses showed that NLRP3 and caspase-1 expressions were increased in the DM group according to the control group and the mirtazapine administration decreased these expressions. The intraglomerular and tubular TUNEL-positive cells were numerous in the DM group compared to the mirtazapine-treated group. The level of IL-1 beta was highest in the DM group, and decreased significantly in the mirtazapine-treated group. Conclusion: In this study, 20 mg/kg/day mirtazapine administration for 2 weeks reduced NLRP3 and caspase-1 expressions and IL-1 beta level in the diabetic rat kidneys. These results suggesting that mirtazapine may be useful in the treatment of DM and other metabolic diseases. Advanced molecular studies are needed to elucidate the exact effects of mirtazapine on NLRP3 inflammasome.