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目的研究视黄酸调节胸腺细胞发育的作用及其机制。方法采用体外胸腺组织培养体系,在培养中加入视黄酸或视黄酸受体拮抗剂。在培养的不同时间收集胸腺细胞,用荧光标记的抗 CD3、CD4、CD8抗体染色,并进行流式细胞仪分析,观察胸腺细胞表面标志随成熟分化的变化。胸腺细胞抽提的 RNA 采用实时定量 PCR 法检测视黄酸受体α(RARα)mRNA 的表达。结果体外胸腺组织培养体系能支持胸腺细胞的发育成熟。在培养24h 视黄酸促进未成熟的CD4~+CD8~+胸腺细胞向 CD4~+成熟细胞分化发育作用明显,并且该作用可被 RARα特异性拮抗剂 Ro41-5253所拮抗。另一方面,视黄酸能显著抑制 CD4~+CD8~+胸腺细胞向CD8~+细胞分化,这种作用也在培养24h 出现。实时定量 PCR 结果显示,视黄酸能促进 RARα mRNA 的表达,并且 RARα mRNA 表达水平与 CD4~+CD8~+胸腺细胞百分数之间存在正相关(r=0.593,P=0.042),与 CD8~+胸腺细胞百分数之间存在负相关(r=-0.654,P=0.021)。结论视黄酸影响胸腺细胞的成熟分化,可能通过影响其受体 RARα表达的途径而发挥调节作用。
Objective To study the effect of retinoic acid on the regulation of thymocyte development and its mechanism. Methods Thymus tissue culture system in vitro, retinoic acid or retinoic acid receptor antagonist was added in the culture. Thymocytes were harvested at different times of culture, stained with fluorescently labeled anti-CD3, CD4, CD8 antibodies, and analyzed by flow cytometry to observe changes in the surface markers of thymocytes with maturation. RNA extracted from thymocytes was used to detect the expression of retinoic acid receptor α (RARα) mRNA by real-time quantitative PCR. Results In vitro thymus tissue culture system can support the thymus maturation. The effect of culturing 24h retinoic acid on immature CD4 ~ + CD8 ~ + thymocytes to differentiate into CD4 ~ + mature cells was obvious, and this effect was antagonized by RARα-specific antagonist Ro41-5253. On the other hand, retinoic acid could significantly inhibit the differentiation of CD4 ~ + CD8 ~ + thymocytes into CD8 ~ + cells. The result of real-time quantitative PCR showed that retinoic acid could promote the expression of RARα mRNA, and there was a positive correlation between RARα mRNA and the percentage of CD4 ~ + CD8 ~ + thymocytes (r = 0.593, P = 0.042) There was a negative correlation between the percentage of thymocytes (r = -0.654, P = 0.021). Conclusion Retinoic acid affects the maturation and differentiation of thymocytes and may play a regulatory role by affecting the expression of its receptor RARα.