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目的探讨叶酸在N-甲基-N-硝基-N-亚硝基胍(MNNG)致哈萨克族(哈族)食管正常上皮细胞增殖、细胞周期及凋亡中的作用。方法采用3因素3水平(33)析因设计将体外培养的哈族食管正常上皮细胞暴露于不同浓度叶酸(0.000、0.400、0.800μg/mL)和MNNG(0.000、0.750、1.500μg/mL)的培养液中作用48、72和96h后,采用噻唑蓝(MTT)法检测叶酸及MNNG对哈族食管上皮增殖的影响,流式细胞术检测细胞周期和细胞凋亡。结果随着叶酸浓度的降低和MNNG浓度增加,哈族食管正常上皮细胞形态发生了明显的变化,死细胞数目逐渐增多,细胞核出现不同程度的破裂,胞质不匀和细胞完整性损伤,细胞对MNNG损害的敏感性明显增加,96h时尤为严重;哈族食管正常上皮细胞的抑制率升高,差异有统计学意义(P<0.05);哈族食管正常上皮细胞G0+G1期、S期和G2+M期细胞比例不同,差异有统计学意义(P<0.05),细胞周期阻滞在S期和G2+M期;哈族食管正常上皮细胞的凋亡率升高,差异有统计学意义(P<0.05)。结论叶酸浓度降低对MNNG致哈族食管正常上皮细胞损伤有一定的促进作用。
Objective To investigate the role of folic acid in the proliferation, cell cycle and apoptosis of normal esophageal epithelial cells in Kazak (Ha ethnic) induced by N-methyl-N-nitro-N-nitrosoguanidine (MNNG) Methods The normal esophageal epithelial cells of Ha nationality esophagus cultured in vitro were exposed to folic acid (0.000,0.400,0.800μg / mL) and MNNG (0.000,0.750,1.500μg / mL) by factorial design of three factors and three levels (33) Effects of folic acid and MNNG on the proliferation of Ha esophageal epithelium were detected by MTT assay after 48, 72 and 96 hours. The cell cycle and apoptosis were detected by flow cytometry. Results With the decrease of folic acid concentration and the increase of MNNG concentration, the morphology of normal esophageal epithelial cells of Ha nationality esophagus changed obviously. The number of dead cells increased gradually, and the nucleus appeared different degree of rupture, cytoplasm unevenness and cell integrity damage. The sensitivities of MNNG were significantly increased at 96h, especially at 96h. The inhibitory rates of normal esophageal epithelial cells in Ha ethnic group were significantly higher than those in normal controls (P <0.05). The G0 + G1 phase, S phase and G2 + M phase cells, the difference was statistically significant (P <0.05), cell cycle arrest in the S phase and G2 + M phase; Kazakh esophageal normal epithelial cell apoptosis rate increased, the difference was statistically significant (P <0.05). Conclusions The decrease of folic acid concentration can promote the normal esophageal mucosal damage induced by MNNG.