The analysis of cerebellar α-synuclein immunohistochemistry showed a significant increase in α-synuclein immunoexpression in the diabetic group compared to the control group (p < 0.01). Conclusion. Due to increased inflammation and oxidative stress in the chronic period of hyperglycemia linked to diabetes, there may be α-synuclein accumulation in the cerebellum and the plasma PTX3 levels may be assessed as an important biomarker of this situation. Here, PTX3 is linked to diabetes mellitus.