HIPPOCAMPAL AND CEREBELLAR HISTOLOGICAL CHANGES AND THEIR BEHAVIOURAL REPERCUSSIONS CAUSED BY BRAIN ISCHAEMIC HYPOXIA EXPERIMENTALLY INDUCED BY SODIUM NITRITE

Abstract Introduction Brain ischaemic hypoxia can produce severe neurological damage that leads to behavioural disorders. This research analysed the hippocampal and cerebellar histological alterations caused by brain ischaemic hypoxia experimentally induced by sodium nitrite (NaNO 2 ) and possible direct repercussions of this hypoxia on behaviour. Methodology An experimental study was carried out by administering 60 mg/kg NaNO 2 to 10 Wistar rats at 3 months of age for 15 consecutive days. Ten control rats did not receive NaNO 2 . To assess behavioural repercussions, the animals were evaluated in Open Field, Elevated Plus-Maze (EPM), and Forced Swim tests before and after injury to evaluate locomotion, anxiety, and depression, respectively. Markers of stress were evaluated by measuring the blood levels of cortisol, glucose, cholesterol, and lactate. The presence of hippocampal lesions was verified by histologically studying the CA1–CA4 areas. Sections of the cerebellum were also evaluated because Purkinje cells are highly sensitive to ischaemic hypoxia and may serve as markers for this process. Results The number of neurons with lesions was significantly higher in animals exposed to NaNO 2 in the hippocampus areas CA2, CA3, and CA4. The cerebellum was also very vulnerable to hypoxia, presenting extensive lesion areas. These results are correlated with the parameters of the anxiety and depression tests. Conclusion NaNO 2 promoted brain damage due to ischaemic hypoxia in rats. Intoxicated animals showed decreased brain weights; damage in hippocampus and cerebellum; and anxiogenic and depressive behaviour.