Protective effect of angelica sinensis polysaccharide on the thymus structure and function of aging model rats

Objective To investigate the protective effect of Angelica Sinensis polysaccharide( ASP) on the thymus structure and function of aging model rats and its relative mechanism. Methods Forty SD rats were randomly divided into 4 groups. Aging model group were injected with D-galactose [120mg /( kg·d) ] for 42 days by subcutaneous way. ASP aging group were also given D-galactose with the same dose and time as aging model group,and from the 14 th day on,rats were maintained with ASP( 100 mg / kg) by intra-peritoneal way for 28 days. Normal control group were received saline with the same volume for 42 days. ASP control group were given saline with the same volume for 14 days,and received ASP( 100 mg / kg) for 28 days by intra-peritoneal way. After 2 days of injections,the thymus index and thymus weight were measured,and paraffin sections were made to observe thymus microscopic structures. The senescence of thymus and the proliferative capacity and cell cycles of thymocytes were measured. The content of cytokines and the production of reactive oxygen species( ROS) and superoxide dismutase( SOD) were detected. Results The thymus structure and function were obviously induced senescence by treating with D-galactose. Comparing the ASP aging group with the aging model group,thymus index,thymus weight,thymus cortex area proportion,the proliferative capacity and proportion of S phase of thymocytes,thymocytes secretary capability of interleukin( IL)-2,tumor necrosis factor( TNF-α),granulocyte-macrophage colony-stimulating factor( GM-CSF), and IL-6, the active content of SOD were obviously increased. The percentage of senescence β-galactosidase( SA-β-Gal) positive thymocytes,and the production of ROS were significantly decreased. Conclusion Angelica Sinensis polysaccharide has a significantly antiaging or protective effect on thymus injury. It is suggested that the mechanism may be ASP inhibiting oxidative stress.