组蛋白去乙酰化酶1在人气管上皮损伤修复过程中的表达

Expression of histone deacetylase 1 during bronchial regeneration in the human

目的检测组蛋白去乙酰化酶1(HDAC1)在人气管上皮损伤修复中的表达及其变化,探讨影响气管干细胞增殖分化的分子调控机制。方法 5-氟尿嘧啶(5-FU)造成人离体气管上皮损伤,应用免疫组织化学和Western blotting方法检测修复过程中各时间点气管上皮HDAC1的表达。结果去除5-FU后0h,气管上皮脱落,仅残留少量G0期细胞,HDAC1表达阴性;3～6h,细胞数量增多,为扁平状,未见明显HDAC1阳性细胞;12h,上皮细胞由扁平变立方并连接成片,HDAC1阳性细胞数明显增多,并可见数个HDAC1阳性细胞围绕着底部1个HDAC1阴性细胞和多个HDAC1阳性细胞间夹着数个HDAC1阴性细胞分布的现象;24h,细胞数继续增多并变复层,HDAC1阳性细胞数最多,累及全层;48h,接近假复层结构,HDAC1阳性细胞数略减少,阳性细胞分布集中于假复层结构顶部即靠近管腔侧;正常气管上皮HDAC1表达阴性。Western blotting分析显示,HDAC1表达量的变化趋势与免疫组织化学结果一致。结论随着气管干细胞分化细胞数增多,HDAC1阳性细胞数明显增多,提示HDAC1可作为气管干细胞由增殖转向分化的分子开关。

Objective To determine the expression and changes of histone deacetylase 1 （HDAC1） during human bronchial regeneration after injury and to explore the molecular mechanisms in proliferation and differentiation of the bronchial stem ceils. Methods The isolated human bronchial epithelium was injured by 5-fluorouracil（5-FU）. HDAC1 expression in bronchial epithelium during the process of regeneration was analyzed by immunohistochemistry and Western blotting. Results 1. At 0 hour after 5-FU treatment, the bronchial epithelium shed and the expression of HDAC1 was negative. During 3-6 hours after the removal of 5-FU,the bronchial rings were covered with flattened epithelial cells and a few of the epithelial ceils were HDAC1 positive. At the 12th hour, the epithelial cells were cuboidal and merged into pieces. The number of the HDAC1 positive cells increased obviously and a few HDAC1 positive cells were around one negative cell. At the 24th hour, the epithelial cells continued to increase and became stratified, HDAC1 was in top expression throughout all layers at this time; At the 48th hour, the epithelium restored similar to the pseudostratified structure,HDAC1 decreased slightly; The expression of HDAC1 was negative in normal bronchial epithelium. 2. Western blotting analysis showed that there were different HDAC1 levels at different times after the removal of 5-FU which in accordance with the change of immunohistochemistry. Conclusion With more differentiating cells appeared, more HDAC1 positive cells were observed, suggesting that HDAC1 can function as a molecular switch of bronchial epithelial stem cells fom proliferation to differentiation.