Effect of Curcumin on Hippocampal Neurons, Learning, and Spatial Memory in a Model of Global Cerebral Ischemia

Background: Curcumin is a natural antioxidant known for its neuroprotective properties against cerebral ischemic reperfusion injury. Stroke has the greatest impact on the hippocampus cornu ammonis (CA1) region and leads to cognitive impairment. Objectives: This study aimed to investigate the effect of pretreatment with turmeric extracts before the induction of cerebral ischemia on the structure of the hippocampus CA1 region, learning, and spatial memory. Methods: A total of 32 adult male Wistar rats were randomly divided into four groups: 1) control group, 2) sham group (received dimethyl sulfoxide), 3) ischemia group (15 min bilateral carotid artery), and 4) curcumin group (received 100 mg/kg of curcumin daily for five days before the induction of ischemia). The Morris water maze test was performed to evaluate memory impairment in mice 48 h after ischemia induction. The animals were then anesthetized, and their blood samples were taken for malondialdehyde measurement. Subsequently, the animals' brains were removed, and the number of neurons, as well as the volume of the layers, were examined using cresyl violet staining. Results: The results of the stereology showed a significant increase in the volume of the CA1 region and its substrates in the curcumin treatment group, compared to the ischemia group. In addition, the number of pyramidal neurons in the treatment group showed a significant increase, in comparison with the ischemia group. Moreover, curcumin administration reduced the spatial memory impairment in the treatment group, compared to the ischemia group. Conclusion: These findings suggest that pretreatment with curcumin can improve memory and learning disorders, as well as hippocampal neuron damage, following ischemia.