Cognitive and anti-inflammatory effects of Palmaria palmata in a schizophrenia mouse model: insights into CREB signaling, Iba-1 expression, and CD4+ cell modulation.

BACKGROUND: Schizophrenia is a prevalent mental illness characterized by complex behavioral and emotional disturbances, with its underlying molecular mechanisms yet to be fully elucidated. AIM: This study aims to examine the neuroprotective effects of Palmaria palmata (Palmaria p.) on cognitive function in a schizophrenia mouse model. METHODS: A total of 28 adult male SWR Swiss mice were used over a 30-day period. The animals were randomly divided into four groups (n = 7): control, cuprizone (CPZ) (0.2% CPZ in chow), CPZ + Palmaria p. (600 μg/kg bw/day via gavage), and Palmaria p. alone. The antioxidant activity of Palmaria p. was assessed using a radical scavenging assay. Behavioral assessments, hippocampal (HC) and frontal cortex (FC) gene expression analyses, and histopathological evaluations were conducted. RESULTS: Palmaria p. demonstrated remarkable antioxidant activity against CPZ-induced oxidative stress. No notable effects were observed in spatial memory, the novel object recognition test (NORT), or anxiety-related behaviors. In the CPZ-treated group, Iba1 and CREB expression levels increased in both the hippocampus (HC) and frontal cortex (FC). In the CPZ + Palmaria p. group, Iba1 expression was reduced by approximately one-fold in the HC and two-fold in the FC, while CREB expression was decreased by approximately two-fold in both regions compared to the CPZ group, indicating attenuation of neuroinflammation and restoration of neuroplasticity. Immunohistochemical analysis revealed a notable decline in CD4(+) expression following Palmaria p. administration, suggesting a decrease in the immunological response induced by CPZ. CONCLUSION: The results highlight the potential of Palmaria p. to enhance neuroplasticity and reduce neuronal inflammation associated with schizophrenia.