中文摘要：

目的探讨当归多糖（ASP）拮抗致衰剂对大鼠胸腺结构与功能的保护作用及相关机制。方法 SD大鼠随机分为4组,每组10只。衰老模型组,每天1次皮下注射D-半乳糖（120mg/kg）,共42d;ASP衰老模型组,每天1次注射D-半乳糖剂量与时间同衰老模型组,第15天起腹腔注射ASP（100 mg/kg）,至第42天;正常对照组,每天皮下注射等量生理盐水42d;ASP对照组,注射等量生理盐水14d,第15天起腹腔注射ASP 28d（同ASP衰老模型组）。药物注射完成后第2天,取各组胸腺,测定胸腺指数,观察胸腺组织形态学,检测胸腺细胞衰老;制备各组胸腺细胞,体外培养细胞检测其增殖、细胞周期分布,测定细胞因子分泌量、细胞产生活性氧（ROS）及超氧化物歧化酶（SOD）含量。结果 D-半乳糖复制的衰老模型大鼠胸腺结构与功能损伤明显。与衰老模型组大鼠比较,ASP衰老模型组大鼠胸腺指数升高,胸腺皮质与髓质面积比例增加,胸腺细胞的增殖能力提高,处于G1期胸腺细胞比例减少,G2及S期细胞比例增加,衰老相关β-半乳糖苷酶（SA-β-Gal）阳性胸腺细胞百分率下降,肿瘤坏死因子α（TNF-α）、粒-巨噬细胞集落刺激因子（GM-CSF）、白细胞介素（IL）-2、IL-6的分泌能力明显提高,SOD活性明显提升,ROS含量下降。结论当归多糖对致衰剂D-半乳糖所致的胸腺损伤有明确的拮抗作用,其机制可能与抑制氧化损伤有关。

英文摘要：

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.