Effect of streptozotocin-induced diabetes mellitus on the cerebellar cortex of adult male albino rats: histological and immunohistochemical study

Introduction: Diabetes mellitus is a common metabolic disorder with well-known serious secondary complications. It is also associated with central nervous system damage. This damage is characterized by impairment in brain functions, with neurochemical and structural abnormalities. Aim of the work: To clarify the effects of streptozotocin-induced diabetes on the histological structure of the cerebellar cortex of adult rats. Materials and methods: Twenty adult male albino rats were used in this study, randomly divided into three groups. Group I was the control group; group II received a single intraperitoneal injection of 0.1 ml saline; and group III received a single intraperitoneal injection of streptozotocin at a dose of 60 mg/kg freshly dissolved in 0.1 ml saline. After 8 weeks, the cerebellum was dissected and processed for light and electron microscopic examinations and also for glial fibrillary acidic protein (GFAP) to demonstrate the astrocytes. Morphometrical and statistical analyses were carried out. Results: In group III, degenerative changes were observed in neurons. Mitochondrial alterations and disarrangement of myelin sheaths with increased area of myelinated axons were observed. Dispersed presynaptic vesicles in swollen axonal terminals were also observed. However, there was good evidence of gliosis, which was supported by a significant increase in the number of GFAP astrocytes. Conclusion: The cerebellar cortex was particularly susceptible to hyperglycemia-induced oxidative stress and could have contributed toward the neuronal damage and increased astrocyte activity.