Lycium barbarum polysaccharides mitigate chronic intermittent hypoxia induced hippocampal oxidative stress, inflammation and apoptosis in rats.

Abstract

BACKGROUND: Chronic intermittent hypoxia (CIH), mimicking severe conditions of obstructive sleeping apnea, induces oxidative stress, inflammation and apoptosis in the hippocampus. Lycium barbarum polysaccharides (LBP) are biological significant portions of traditional Chinese herbal medicine Goji, which possess anti-oxidative and anti-inflammatory properties. OBJECTIVES: Our study aims to investigate the neuroprotective effect of LBP in CIH rats. We hypothesize that LBP ameliorate oxidative stress, inflammation and apoptosis in the hippocampus of rats exposed to CIH. METHODS: MDA assay was used to measure the lipid peroxidation extent, a marker of oxidative stress. Western blot was employed to examine the expressions level of antioxidant enzymes (SOD-1, SOD-2); inflammatory mediators (IL-1β], TNFα, COX-2); caspase-dependent extrinsic (FADD, caspase 8, Bid) and intrinsic apoptotic (Bax, Bcl2, cytochrome C) cell death (cleaved caspase 3) cascades; proliferative marker (PCNA) and trophic factor (BDNF). In situ cell death staining (TUNEL) was utilized to reveal the apoptotic situation of hippocampal subfields (DG, CA1 and CA3). RESULTS: LBP administrations remarkably attenuated the level of oxidative stress, inflammation and apoptosis in the hypoxic group. In addition, LBP significantly mitigated caspase-dependent apoptotic extrinsic and intrinsic (Bax, Bcl2, cytochrome C) cascades in the hypoxic group. Surprisingly, LBP increased the expression of proliferative marker (PCNA) and trophic factor (BDNF) in the hypoxic group. CONCLUSION: LBP are neuroprotective against CIH-induced hippocampal injury and may facilitate CIH-induced neurogenesis.