Oral ingestion of plasmalogens can attenuate the LPS-induced memory loss and microglial activation

Plasmalogens (Pls) are the special phospholipids which were reported to be reduced in brain and blood samples of Alzheimer's disease (AD) patients, suggested a possibility that an oral ingestion of Pls may prevent the disease progression. Interestingly, the clinical study showed that the daily oral ingestion of Pls among the mild AD patients improved cognition. However, it is unknown of whether the oral ingestion of Pls inhibits the AD like changes in brain e.g., glial activation and accumulation of amyloid beta (Aβ) proteins. To elucidate the beneficial effects of the Pls oral ingestion, we have used the chronic lipopolysaccharide (LPS) injection model mice where the glial activation and Aβ accumulation were well reported. In the present study, we have found that the Pls drinking at the doses of 0.1 μg/ml and 10 μg/ml for 3 months attenuated the glial activation and accumulation of amyloid beta (Aβ) proteins in the murine brain. Interestingly, the LPS injection reduced the hippocampal dependent memory in the control mice but the groups of Pls drinking mice showed a better performance in the memory test, suggesting that oral intake of Pls can inhibit LPS-mediated memory loss associated with a reduction of glial activation and Aβ accumulation in the brain. We, therefore, suggest that the oral ingestion of Pls among the AD patients may also inhibit the glial activation resulting in the improvement of cognition.