目的 观察淫羊藿苷(Icrrin,ICA)对组蛋白去乙酰化酶SIRT6的激活作用及对老年小鼠体内NF-κB(p65)、SIRT6蛋白表达及NF-κB信号通路下游炎症细胞因子表达的影响.方法 以体外酶学实验观察ICA对SIRT6的激活作用并绘制不同剂量浓度激活效率曲线.选取24月龄老年组(n=11)、24月龄+ICA干预组(n=12)和3月龄青年组小鼠(n=10)的心、肝、肌肉组织,用Western blot检测NF-κB(p65)和SIRT6蛋白表达水平；采用ELISA法检测小鼠血清中肿瘤坏死因子α (TNF-α)、细胞间粘附分子-1(ICAM-1)、白细胞介素-2(IL-2)和白细胞介素-6(IL-6)的含量.结果 体外酶学实验显示ICA随着药物浓度的下降,对SIRT6逐渐呈现激活效应,在10-8 mol/L浓度时达到最大激活效应为142％.小鼠实验显示ICA干预后,心脏、肝脏与肌肉组织中NF-κB (p65)蛋白表达与老年小鼠比较呈现下调趋势,而SIRT6蛋白表达较老年小鼠则呈现上调趋势；与青年小鼠比较,老年小鼠血清中炎症细胞TNF-α、ICAM-1、IL-2、IL-6的含量均明显上调(P＜0.05、P＜0.01)；与老年小鼠比较,ICA干预后小鼠血清中炎症因子TNF-α、ICAM-1、IL-2、IL-6的含量均明显下降(P＜0.05、P＜0.01).结论 ICA对SIRT6的酶活性具有显著的激活效应,且在极低的药物浓度下仍对SIRT6有激活作用；ICA能上调老年小鼠组织中SIRT6蛋白表达,抑制NF-κB(p65)蛋白表达及下调下游炎症细胞因子的产生,提示ICA延缓炎性衰老的作用机制及干预新靶点与NF-κB信号通路和组蛋白去乙酰化酶SIRT6密切相关.%Objective To investigate the effect of Icarrin (ICA) on the enzymatic activity of histone deacetylase SIRT6, protein expression of SIRT6 and NF-κB (p65) as well as the expression of down-stream inflammatory genes of NF-κB inflammatory signaling transduction. Methods The effect of Icarrin on SIRT6 enzymatic activity was evaluated by using in vitro enzyme assays, and the dose-dependent stimulating efficacy curves were drawn out. Mice were allocated into 3 groups: 24 months old mice (n = 11), 24 months old mice treated with ICA (n = 12) and 3 months young mice (n = 10). The levels of protein of SIRT6 and NF-κB (p65) in the hearts, livers and muscle tissues of mice were assessed by Western blot, while the serum levels of TNF-α, ICAM-1, IL-2 and IL-6 were evaluated by ELISA. Results ICA showed positive stimulating efficacy upon SIRT6 enzymatic activity with the dose descending and reached its peak value as 142% at the concentration of 10-8 mol/L. Compared with the 24 month old mice group, the levels of protein expression of SIRT6 in mice hearts, livers and muscle tissues showed up-regulating tendency, while NF-κB (p65) expression down-regulated after treated with ICA. The serum levels of TNF-α, ICAM-1, IL-2 and IL-6 in 24 months old mice were significantly higher than those in the 3 months young mice group (P<0.05, P<0.0.1). Compared with the 24 months old mice group, the levels of TNF-a, ICAM-1, IL-2 and IL-6 in the old mice treated with ICA were significantly decreased (P<0.05,P < 0.0.1). Conclusions ICA has positive stimulating efficacy upon SIRT6 enzymatic activity, even at its very low concentration. ICA up-regulates SIRT6 protein expression, down-regulates NF-κB (p65) protein expression, and reduces the related inflammatory factors in old mice. The new underlying mechanism and target of anti-inflamm-aging efficacy of ICA may closely relate to histone deacetylase SIRT6 and NF-κB signaling transduction.
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