玛咖多糖对D-半乳糖衰老模型小鼠免疫器官的保护作用

Protective Effect of Polysaccharide from Lepidium meyenii Rhizome on Immune Organs of Aging Mice

目的:研究玛咖多糖对D-半乳糖(D-gal)所致亚急性衰老小鼠免疫器官氧化损伤的保护作用及其作用机制。方法:50只ICR小鼠随机分为5组,分别为正常组,D-gal模型组,玛咖多糖低、中、高剂量组。每日ihD-半乳糖500 mg·kg^(-1)造模,玛咖多糖给药组另ig玛咖多糖溶液(75,150,300 mg·kg^(-1)),连续造模给药56 d测定小鼠血清或肝脏组织中超氧化物歧化酶(SOD),过氧化氢酶(CAT),谷胱甘肽过氧化物酶(GSH-Px),单胺氧化酶(MAO)活性及丙二醛(MDA)含量,透射电镜下观察玛咖多糖对D-gal损伤小鼠胸腺组织影响,并用实时荧光定量聚合酶链式反应(q PCR)检测脾脏组织p53,SOD2,CAT在mRNA水平表达情况。结果:与正常组比较,模型组细胞出现脾窦扩张,核周间隙大,染色质边集,部分细胞出现凋亡,模型组小鼠血清SOD,CAT活性明显降低,MDA含量明显升高,小鼠肝脏中SOD,GSH-Px活性明显降低,MAO活性及MDA含量明显升高,小鼠脾脏组织p53 mRNA明显升高,SOD2,CAT mRNA明显降低(P<0.05,P<0.01);与模型组比较,玛咖多糖中、高剂量组胸腺组织中淋巴细胞分布较为均匀,核周分界清晰,胞浆内无空泡,玛咖多糖给药组能明显提高小鼠血清SOD,CAT活性,明显降低MDA含量,明显升高SOD,GSH-Px活性,降低MAO活性及MDA含量,玛咖多糖高剂量组明显下调小鼠脾脏p53mRNA水平,中、高剂量组明显升高CAT mRNA水平,高剂量组明显升高SOD2 mRNA水平(P<0.05,P<0.01)。结论:玛咖多糖对致衰老模型小鼠免疫器官有保护作用,可能机制是提高抗氧化酶活性及抗氧化酶在基因水平的表达,降低老化相关酶活性。

Objective： To explore the effects of polysaccharide from Lepidium meyenii raizomel（ PLR）on the immune organs in subacute aging mice induced by D-galactose,and investigate its action mechanism.Method： Fifty ICR mice were randomly divided into five groups： normal group,D-galactose model group,and PLR low-,middle-,and high-dose groups. 500 mg·kg-1 of D-galactose was given to the mice by ih administration to produce aging models. The mice in PLR groups were given with PLR solution（ 75,150,300 mg·kg-1） by ig administration. The drugs were given for 56 days,and then the activities of superoxide dismutase（ SOD）,catalase（ CAT）,glutathion peroxidase（ GSH-Px）,monoamine oxidase（ MAO） and the content of malondialdehyde（ MDA） in mice serum or liver tissues were detected; the thymus ultrastructural changes were observed under TEM; the mRNA expression levels of SOD,CAT and p53 in the spleen were determined by q PCR. Result： As compared with the normal group,splenic sinusoid was extended in cells of model group,with large perinuclear space and chromatin margination; apoptosis was present in some cells; the SOD and CAT activities in serum of model group mice were significantly decreased; p53 mRNA expression in spleen tissues was significantly increased;SOD2 and CAT mRNA expressions were significantly decreased（ P 〈 0. 05,P 〈 0. 01）. As compared with the model group,distribution of lymphocytes in thymus was even in PLR middle dose and high dose groups; with clear perinuclear boundaries; no vacuoles in the cytoplasm; PLR could enhance the activities of SOD,CAT,GSH-Px,and reduce the content of MDA and activity of MAO. PLR high dose group significantly down-regulated the expression of p53 mRNA in spleen; middle dose and high dose groups significantly increased CAT mRNA expression; high dose group significantly increased SOD2 mRNA level（ P 〈 0. 05,P 〈 0. 01）. Conclusion： PLR has a protective effect on the immune organs of aging mice models,and the mechanism may be associated with increasing antioxidant enzyme activity and antioxidant enzyme mRNA expression,and decreasing aging-related enzyme activity.