The effects of astragalus polysaccharide on zebrafish cell apoptosis and senescence

Abstract

Astragalus polysaccharide (AP) is the extraction of astragalus, which is a plant used in traditional Chinese herb medicine and may increase an orgainism’s resistance to stress. Several earlier studies in vitro have indicated that AP has anti-aging activities, however the mechanism underlyling these activities was unclear and remained to be elucidated. In this study, Using the zebrafish (Danio rerio), we evaluated molecular mechanism of the effect of AP on zebrafish growth, development and apoptosis. 30 zebrafish embryos (24 hours post fertilization (hpf)) were exposed to varying concentrations of AP (from 0.125 mg/ml to 0. 5 mg/ml) continuously for 3 days. The results of β-galactosidase (SA-β-gal) and acridine orange fluorescence showed that AP can delay zebrafish embryos apoptosis under the concentration of 0.125 mg/ml. In addition, the differential gene expression of AP treated zebrafish embryos was examined by RT-PCR analysis. We found that the gene expression of mdm2 and tert were up-regulated while bax, p21 and p53 gene expression were down-regulated during early apoptosis of the zebrafish embryos mediated by AP. These results demonstrated that AP may play a role during the induction of senescence and this function might by p53-mediated pathway.