Lychee Seed Fraction Inhibits Aβ(1-42)-Induced Neuroinflammation in BV-2 Cells via NF-κB Signaling Pathway

In our previous studies, an active fraction derived from lychee seed could inhibit β-amyloid-induced apoptosis of PC12 cells and neurons. The primarily microglia cells are recognized as the brain's resident macrophages and thought to remodel of the brain by removing presumably redundant, apoptotic neurons. In the current study, we aimed to investigate the anti-neuroinflammation effect of lychee seed fraction (LSF) in Aβ(1-42)-induced BV-2 cells and the underlying mechanism. The morphology results displayed that LSF could improve the status of Aβ(1-42)-induced BV-2 cells. The enzyme-linked immunosorbent assay, real-time PCR, and Western blotting results showed that LSF could significantly reduce the release, mRNA levels, and protein expressions of the pro-inflammatory cytokines such as interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in Aβ(1-42)-induced BV-2 cells, which were downregulated through suppressing the NF-κB signaling pathway. Furthermore, LSF could upregulate Bcl-2 and downregulate Bax, Caspase-3, and cleaved-PARP protein expressions. Taken together, our results first demonstrated that LSF could suppress the inflammatory response via inhibiting NF-κB signaling pathway, and inhibit apoptosis in Aβ(1-42)-induced BV-2 cells. Our findings further prove that LSF as a potential drug may be used for treating AD in the future.