| Objective: To investigate the effect of curcumin on behavior performance in theSTZ-induced diabetic rats and on histopathology in the hippocampal neurons.Methods: Male SD rats were randomised into three groups: the normal controlrats(Con), the diabetic model rats(DM) and the curcumin-treated diabetic rats(DM+Cur). The performance differences of these groups were examined in watermaze. The morphological changes in the hippocampus and cerebral cortex wereobserved through HE staining. By western blotting analysis, the levels ofapoptosis-related Bcl-2and Bax were determined in the hippocampus. And byimmunohistochemistry assay, the activation of caspase-3was measured.Results: The blood glucose elevated and the body mass of diabetes rats decreasedwhen compared to the normal subjects. Such symptoms similar to type2diabetes maybe improved in the curcumin-treated diabetes rats. During water maze tasks,trajectories of the diabetes rats were observed more intricate, and the escape latencieswere longer than the normal rats. Howerver, the times for rats crossing the platformlocation reduced when compared to the withdrawal of the water maze platform. Inadditon,the behavior performance and cognition ability of learning and memory in thediabetic individuals treated with curcumin for16weeks may be improved whencompared to the diabetes group. In histological studies, STZ diabetic rats displaymorphological changes in the hippocampus, including dendritic atrophy in the CA3pyramidal neurons, decreased synapse number, and decreased immunoreactiveinterneurons in the CA1region. Curcumin reduced the degeneration occurrence ofhippocampal neurons when compared the curcumin-treated diabetes rats to thediabetes group. Further studies of the molecular mechanisms exhibited that theactivation levels of caspase-3associated with apoptosis enhanced in diabetes rats thanin the control(p<0.05), while the activation declined when compared to thecurcumin-treated group. Additionally, the ratio of Bcl-2/Bax in the hippocampus indiabetes rats decreased when compared to normal rats(p<0.05), but the ratio increased,as compared to the diabetes subjects.Conclusion: Curcumin inhibited the diabetes-induced pathological changes in thehippocampal neurons, and improved the learning and memory performance, whichmay be achieved via the mechanisms of Bcl-2/Bax and caspase-3pathways. |
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