Abstract: Objective The effect of angelica sinensis polysaccharides (ASP) on the expression of contol cell cycle protein in mice hematopoietic stem cells (HSCs) were observed to explore the underlying mechanism that ASP delay aging of HSCs in vivo. Methods C57BL/6J mice were randomly divided into control group, ASP regulate control group, aging group, ASP regulation aging group. Mice were uniformly explored in X-ray to erect model of aging. ASP regulation aging groups mice were treated with ASP by intragastric administration during X-ray irradiation. While control and ASP regulation control groups were treated with equal-volume NS and ASP by intragastric administration. Mouse HSCs were isolated by magnetic cell sorting and cultured in vitro. Senescence-associated β-galactosidase (SA-β-Gal) staining was used to detect aging HSCs. Cell cycles analysis and CFU-Mix cultivation were used to evaluate the capability of colony forming in HSCs. Cell cycles were detected by flow cytometry. The expressions of p16, p21,CDK2,CDK6, cyclinD and cyclinE were determined by western blot analysis. Results Exogenous X-ray irradiation induced HSCs aging was compared with control group. Biological feature of HSCs in aging group as follows: The percentage of SA-β-Gal positive cells, the ratio of G1 stages and the expression of p16 and p21 protein were significantly increased , the expression of CDK6、CyclinD、CyclinE, the ratio of S stages and the capacility of colony forming in HSCs were decreased. ASP could significantly decrease the number of SA-β-Gal positive cells, the ratio of G1 stages and downregulate the expression of p16 and p21 protein in HSCs contrast to aging control group. In addition, ASP could remarkably increase the ratio of S stages, the capacility of colony forming and upregulate the expression of CDK6、CyclinD、CyclinE in HSCs compared with aging group. There was no significant difference in the protein expression of CDK2 in HSC. Conclusions ASP could delay senescence HSCs aging which maybe partly ascribed to the regulation of o cell cycle control gene.

Key words: Angelica sinensis polysaccharides, Hematopoietic stem cells, Cell aging, Cell cycle