Introduction: Alzheimer's disease (AD) is a complex neurodegenerative condition with multiple contributing factors, leading to the decline in memory, behavioral changes, and impaired daily functioning. Research has demonstrated that intracerebroventricular streptozotocin (ICV STZ) induces cognitive impairment in rats by promoting the accumulation of free radicals within the brain. Spirulina contains chlorophyll, a green pigment known for its antioxidative capabilities and potential detoxification benefits. In this current study, we conducted an investigation into the impact of Spirulina on cognitive impairment induced by ICV administration of STZ, along with an evaluation of its effect on superoxide dismutase (SOD) activity in rats."Materials and methods: In this study, 30 adult male rats were randomly divided into 3 groups. Control group, STZ group (3 mg/kg, ICV), STZ group treated with spirulina (50 mg/kg, 21 days by gavage). Learning behavior and memory were assessed using novel object recognition. On the 21st day of the experiment, the rats were euthanized for the purpose of assessing SOD activity within the hippocampal region. Results: STZ significantly (**P < 0.01 and ***P < 0.001) caused learning and memory impairment in rat. It also significantly (***P < 0.001) decreased the activity of SOD in hippocampal in STZ group. Spirulina treatment significantly (+++P < 0.001) increases the time and frequency of exploration between the novel object and the old object compared to the STZ group. Therefore, it indicates that spirulina improved recognition memory consolidation. Also, the activity of SOD antioxidant enzyme in rats treated with spirulina increased significantly (+++P < 0.001) compared to STZ group. Conclusion: "Spirulina demonstrated the potential to mitigate cognitive impairments and restore superoxide dismutase (SOD) activity changes induced by streptozotocin (STZ) in the hippocampus. These findings suggest that spirulina could be a promising candidate for therapeutic interventions in Alzheimer's disease."
