衰老对大鼠结肠干细胞增殖分化功能及微环境的影响

Effects of aging on colon stem cells and microenvironment in rat

目的探讨衰老对大鼠结肠干细胞增殖分化功能及微环境的影响。方法雄性SD大鼠按不同月龄分成:成年组(6月龄)、老年组(24月龄),每组10只。采用高碘酸-雪夫试剂(PAS)染色和阿利新蓝染色检测大鼠结肠杯状细胞数量的变化,免疫组化检测各组大鼠结肠干细胞增殖细胞核抗原(PCNA)、β-catenin、糖原合成酶激酶(GSK)-3β蛋白的表达,RT-PCR检测各组大鼠结肠干细胞MUC1、MUC2、Lgr5、Bmi-1的变化。结果与成年组比较,老年组大鼠结肠组织干细胞标记物Lgr5、Bmi-1 mRNA表达量显著降低(P<0. 01),细胞增殖相关蛋白PCNA表达显著增加(P<0. 01),杯状细胞数量和MUC1、MUC2 mRNA表达显著降低(P<0. 01),其微环境Wnt/β-catenin信号通路中的β-catenin蛋白显著增加(P<0. 05)、GSK-3β表达显著降低(P<0. 01)。结论衰老过程中,大鼠结肠干细胞增殖功能增加,向杯状细胞分化的功能减弱,干细胞微环境Wnt/β-catenin信号通路上调。

Objective To investigate the changes of rat colon stem cells and their microenvironment of Wnt/β-catenin signaling pathway during the aging process.Methods Male SD rats at different developmental stages were divided into adult group(6 months)and aging group(24 months),10 rats in each group.Routine periodate and Schiff reagent(PAS) staining,alcianblue staining,immunohistochemistry and RT-PCR were used to detect changes in adult group and aging group colon stem cell proliferation and differentiation and Wnt/β-catenin signaling pathway.Results Compared with those of adult group,the number of goblet cells in aging group were decreased(P<0.01),mRNA expressions of stem cell markers Lgr5,Bmi-1,MUC1,MUC2 were reduced(P<0.01),the expression of PCNA was increased(P<0.01),the microenvironment Wnt/β-catenin signaling pathway related proteinβ-catenin expression was increased( P< 0.05),the expression of GSK-3β was decreased(P<0.01).Conclusions During the rat aging process,the number of colon stem cells and the globet cell differentiation of intestinal stem cells are reduced,the proliferation of colon stem cells are increased,Wnt/β-catenin signal pathway is up-regulated.