1- Department of Anatomy, Faculty of Basic Medical Sciences, Adeleke University, Ede, Osun State, Nigeria , amedunath11@gmail.com
2- Department of Anatomy, Faculty of Basic Medical Sciences, Adeleke University, Ede, Osun State, Nigeria
2- Department of Anatomy, Faculty of Basic Medical Sciences, Adeleke University, Ede, Osun State, Nigeria
Abstract: (138 Views)
Background: The hippocampus, a key region for learning and memory, is influenced by hormonal treatments, which have been shown to alter cognitive functions and hippocampal microstructure. This study investigates the effects of ethinylestradiol (EE) and levonorgestrel (LNG) administration on cognitive flexibility, neurochemical changes, and structural alterations in the rat hippocampus.
Methods: Forty adolescent female Wistar rats were divided into four groups (n=10). The control group (Group A) received only distilled water for 21 days. Groups B, C, and D were administered combined oral contraceptives (COC) containing EE and LNG at doses of 0.03 mg/kg and 0.15 mg/kg, respectively, for 7, 14, and 21 days. Y-maze tests were performed to assess learning and memory. A histological study of the hippocampus was conducted using H&E staining. The levels of dopamine, acetylcholinesterase, malondialdehyde, superoxide dismutase, and interleukin-1β were subsequently assessed using biochemical techniques.
Results: Administration of EE/LNG (21 days) significantly enhanced cognitive flexibility, as shown by a higher alternation percentage in the Y-maze test. Neurochemical analysis revealed increased dopamine levels, oxidative stress (MDA), and decreased antioxidant activity (SOD) with prolonged treatment. Acetylcholinesterase activity was significantly higher in the 21-day group. Hippocampal pyramidal cell counts increased significantly in the EE/LNG 21 days compared to the control for both CA1 (183,076 ± 7,900) and CA3 (284,234 ± 9,205) regions with treatment duration. Histopathological analysis showed distorted dentate gyrus (DG) regions.
Conclusion: Prolonged EE/LNG treatment enhances cognitive flexibility in rats, likely mediated by neurochemical and structural changes in the hippocampus. However, the associated oxidative stress and alterations in acetylcholinesterase activity, along with observed histopathological changes, highlight potential risks to hippocampal integrity and neurogenesis, warranting further investigation into the long-term implications of such treatments.
Article Type: Research |
Subject:
Neuroscience
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