视黄酸对肿瘤坏死因子α诱导肺泡上皮细胞损伤的保护作用

目的探讨肿瘤坏死因子α(TNF-α)对肺泡Ⅱ型上皮细胞株A549增殖凋亡的影响与视黄酸(RA)对其调控作用。方法用不同浓度的TNF-α、1μmol/LRA和10μg/LTNF-α+1μmol/LRA处理肺泡Ⅱ型上皮细胞株A549细胞24h和48h后MTT法测定细胞增殖能力,流式细胞仪检测细胞凋亡。用10μg/LTNF-α处理24h或48h后继续培养,用台盼蓝染色计算24、48和72h活细胞数。结果分别用0、0.1、1、5、10μg/L浓度的TNF-α培养A549细胞24h和48h测定细胞增殖数(%):24h分别为95.0%、90.0%、79.6%、72.4%和59.6%,方差分析结果F值为18.04,P<0.01;48h分别为93.2%、82.7%、61.5%、50.3%和44.7%,F值为40.61,P<0.01。用10μg/LTNF-α处理A549细胞24h,其对细胞的增殖抑制作用可逆转,但处理48h后的A549细胞增殖抑制作用不能逆转。用TNF-α和视黄酸培养A549细胞12、24与48h后,凋亡的细胞数(%)TNF-α组分别为14.3%±3.2%、18.6%±2.9%和43.4%±3.5%,与对照组(6.3%±1.2%,8.2%±1.3%和26.1%±2.5%)比较差异有统计学意义;视黄酸加TNF-α组为4.8%±1.1%,5.2%±1.3%和16.4%±2.3%,明显少于TNF-α组。结论视黄酸通过抑制TNF-α对肺泡Ⅱ型上皮细胞的破坏,可以达到减轻肺泡上皮细胞损伤,保护肺表面活性物质的作用。

Retinoic acid inhibits tumor necrosis factor-alpha induced injury in human lung epithelial cells

OBJECTIVE: To study the effect of tumor necrosis factor-alpha (TNF-alpha) on the proliferation and apoptosis of type II lung alveolar epithelial cells and the regulation of retinoic acid (RA) to this effect. METHODS: Human type II lung alveolar epithelial cells of the line A569 were cultured and divided into 2 groups: control group (cultured in culture fluid only), TNF-group (cultured in the culture fluid with TNF-alpha 10 micromol/L for 24 or 46 h respectively), RA group (cultured in culture fluid without RA 1 microg/L), and TNF-alpha plus RA group (cultured in culture fluid with TNF-alpha 10 micromol/L + RA 1 microg/L). MTT method was used to test the proliferation of the A549 cells. The cell apoptosis was detected by flow cytometric assay. RESULTS: The proliferation rates of A549 cells treated with TNF-alpha of the concentrations of 0, 0.1, 1, 5, and 10 microg/L were 95.0%, 90.0%, 79.6%, 72.4%, and 59.6% after 24 h (F = 18.04, P < 0.001), and were 93.2%, 82.7%, 61.5%, 50.3%, and 44.7% after 48 h (F = 40.61, P < 0.0001). The inhibition effect on the proliferation of A549 cells treated with 10 microg/L TNF-alpha for 24 h could be reversed, however, the inhibition effect on the proliferation of A549 cells treated with 10 microg/L TNF-a for 48h could not be reversed. RA alone did not significantly promote the proliferation of the A549 cells, but weakened the inhibitory effect of TNF-alpha on the proliferation of the A549 cells. The apoptotic rate of the A549 cells treated with TNF-alpha for 12 h, 24 h and 48 h respectively were 14.3% +/- 3.2%, 18.6% +/- 2.9%, and 43.4% +/- 3.5% respectively, all significantly higher than those of the control group (6.3% +/- 1.2%, 8.2% +/- 1.3%, and 26.1% +/- 2.5% respectively, all P < 0.01), and the apoptotic rate of the A549 cells treated with both TNF-alpha and RA for 12 h, 24 h, and 48h were 4.8% +/- 1.1%, 5.2% +/- 1.3%, and 16.4% +/- 2.3% respectively, all significantly lower than those of the TNF-alpha group (all P < 0.01), and the apoptotic rates of the A549 cells treated with both TNF-alpha and RA for 24 h and 48 h respectively were both significantly lower than those of the control group (both P < 0.05). CONCLUSION: RA relieves the injury of alveolar epithelial cells and protects the pulmonary surfactant by inhibiting the destruction of TNF-alpha to type II lung alveolar epithelial cells.