The Effect of Lycium barbarum Polysaccharides on Pyroptosis-Associated Amyloid β(1-40) Oligomers-Induced Adult Retinal Pigment Epithelium 19 Cell Damage

Age-related macular degeneration (AMD) is a sight-threatening disease with limited treatment options. We investigated whether amyloid β(1-40) (Aβ(1-40)) could cause pyroptosis and evaluated the effects of Lycium barbarum polysaccharides (LBP) on Aβ(1-40) oligomers-induced retinal pigment epithelium 19 (ARPE-19) damage, which is an in vitro AMD model. Aβ(1-40) oligomers verified by Western blot were added to ARPE-19 cells with or without 24 h LBP treatment. Aβ(1-40) oligomers significantly decreased ARPE-19 cell viability with obvious morphological changes under light microscopy. SEM revealed swollen cells with a bubbling appearance and ruptured cell membrane, which are morphological characteristics of pyroptosis. ELISA results showed increased expression of IL-1β and IL-18, which are the final products of pyroptosis. LBP administration for 24 h had no toxic effects on ARPE-19 cells and improved cell viability and morphology while disrupting Aβ(1-40) oligomerization in a dose-dependent manner. Furthermore, Aβ(1-40) oligomers up-regulated the cellular immunoreactivity of pyroptosis markers including NOD-like receptors protein 3 (NLRP3), caspase-1, and membrane N-terminal cleavage product of GSDMD (GSDMD-N), which could be reversed by LBP treatment. Taken together, this study showed that LBP effectively protects the Aβ(1-40) oligomers-induced pyroptotic ARPE-19 cell damages by its anti-Aβ(1-40) oligomerization properties and its anti-pyroptotic effects.