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目的维生素 A 缺乏仍是发展中国家儿童的常见病,严重威胁儿童的健康。给予足量的维生素 A 可有效预防感染性疾病并降低死亡率,这种作用可能与维生素 A 及其活性代谢产物视黄酸(retinoic acid,RA)的免疫调节作用有关。维生素 A 对免疫系统的影响正日益被人们所关注。本研究通过检测胸腺细胞发育过程中 Notch1 mRNA的表达变化,并观察视黄酸对其表达的影响,初步探讨 Notch1信号途径在视黄酸对胸腺细胞分化发育中的作用。方法采用胸腺组织体外培养的方法,在培养中加入视黄酸受体活化剂-全反式视黄酸(atRA)或视黄酸受体拮抗剂-Ro41 5253。在培养的不同时间收集 T 细胞,用荧光标记的抗 CD3、CD4、CD8抗体染色,应用流式细胞仪进行分析,观察胸腺细胞成熟分化表面标志的变化。实时定量 PCR 检测培养过程中 Notch1 mRNA 的表达变化。结果采用流式细胞仪分析视黄酸受体的活化与阻抑对胸腺细胞成熟分化的影响,结果显示,在加入 RA 激活视黄酸受体后24h,CD4~+胸腺细胞明显增加,与对照组相比差异显著(P<0.05)。胸腺细胞表达 Notch1 mRNA,实时定量 PCR 结果显示,在 atRA 作用下,胸腺细胞 Notch1 mRNA 的表达在培养24h 即明显下降,与 CD~+胸腺细胞的变化负相关。结论视黄酸能下调胸腺细胞表达 Notch1 mRNA,Notch1信号途径可能参与了视黄酸对胸腺细胞发育的调节作用。
The lack of vitamin A deficiency is still a common disease in children in developing countries and seriously threatens the health of children. Adequate doses of vitamin A can effectively prevent infectious diseases and reduce mortality, which may be related to the immunomodulatory effects of vitamin A and its active metabolite retinoic acid (RA). The impact of vitamin A on the immune system is increasingly being of concern. In this study, we examined the effect of retinoic acid on the expression of Notch1 mRNA in thymic cells and the effects of retinoic acid on the differentiation and development of thymocytes. Methods Thymocytes were cultured in vitro by adding retinoic acid receptor activator - all - trans retinoic acid (atRA) or retinoic acid receptor antagonist - Ro41 5253. T cells were harvested at different times of culture, stained with fluorescently labeled anti-CD3, CD4, CD8 antibodies and analyzed by flow cytometry to observe the changes of mature differentiated surface markers of thymocytes. Real-time quantitative PCR detection of Notch1 mRNA expression changes during culture. Results The effect of retinoic acid receptor activation and repression on thymocyte maturation and differentiation was analyzed by flow cytometry. The results showed that the CD4 ~ + thymocytes were significantly increased 24 h after the RA-activated retinoic acid receptor was added, as compared with the control Group difference was significant (P <0.05). The expression of Notch1 mRNA in thymus cells was detected by real-time quantitative PCR. The expression of Notch1 mRNA in thymus cells decreased significantly at 24h after atRA treatment, which was negatively correlated with the changes of CD ~ + thymocytes. Conclusion Retinoic acid can down-regulate the expression of Notch1 mRNA in thymus cells. Notch1 signal pathway may be involved in the regulation of thymocyte development by retinoic acid.