Inhibitory effect of Lycium barbarum polysaccharides on cell apoptosis and senescence is potentially mediated by the p53 signaling pathway

Abstract

Lycium barbarum (L. barbarum) fruit or extract has been regarded as a superior-grade Chinese medicine, used to modulate body immunity and for anti-aging purposes. However, the underlying molecular mechanisms behind these effects remain unclear. In the present study, L. barbarum polysaccharides (LBPs), considered a major contributor of L. barbarum effects, were used to elucidate its mechanism of action by phenotypic and senescence associated-β-galactosidase (SA-β-gal) assays, evaluation of survival rates in vivo and expression profiling of genes related to the p53 signaling pathway in a zebrafish model. Zebrafish embryos were continuously exposed to various concentrations of LBPs (1.0, 2.0, 3.0 and 4.0 mg/ml) for 3 days. The results of fluorescent acridine orange and SA-β-gal staining indicated that cell apoptosis and senescence mainly occur in the head at 24 hours post fertilization (hpf) and 72 hpf. In addition, resistance to replicative senescence was observed at low doses of LBPs, especially at the 3.0 mg/ml concentration. Furthermore, the expression of genes that relate to aging, such as p53, p21 and Bax, was decreased, while that of Mdm2 and TERT genes was increased after treatment with LBPs. The results demonstrated that the effects of LBPs on cell apoptosis and aging might be mediated by the p53-mediated pathway.