氟对大鼠脑细胞DNA的损伤及诱导凋亡的作用

目的　探讨氟对大鼠脑细胞DNA的损伤作用及诱导凋亡的作用。方法　体内试验中 ,对照组大鼠腹腔注射蒸馏水 ,氟组大鼠注射氟化钠 ,染毒剂量为 2 0mg·kg- 1 ·d- 1 ;体外试验中 ,采用 5mmol/L氟化钠对急性分离的大脑神经细胞染毒 2h后用单细胞凝胶电泳技术 (SCGE)研究氟对细胞DNA的损伤 (单链断裂 )。采用TUNEL法和流式细胞术 (FCM)检测细胞凋亡。结果　体内试验氟组大鼠大脑皮层神经细胞DNA损伤情况明显比对照组严重 ,Ridit值分别为 0 351和 0 639,体外试验对照组与氟组Ridit值分别为 0 650 1和 0 3844。TUNEL阳性细胞在氟组大鼠大脑皮层、海马及小脑颗粒细胞层均可见到 ,在对照组大鼠则很罕见。流式细胞术检测结果表明大脑皮层及海马神经细胞凋亡百分率氟组 (2 7 1 2± 3 0 8,34 97± 5 46)均高于对照组 (4 63± 0 98,5 35± 0 79) ,差异有极显著性意义。结论　氟化钠可引起大鼠脑细胞DNA损伤和细胞凋亡发生

Studies on DNA damage and apoptosis in rat brain induced by fluoride

OBJECTIVE: To explore the DNA damage effects and apoptosis in brain cells of rats induced by sodium fluoride. METHODS: SD rats were divided into two groups, i.e. control group and fluoride treated group, which were injected intraperitoneally with distilled water and sodium fluoride (20 mg.kg(-1).d(-1)) respectively. On the hand, 5 mmol/L NaF were used in in vitro study. Single Cell Gel Electrophosis (SCGE or Comet Assay) was utilized to measured DNA damage and apoptosis was detected by the TUNEL method and Flow Cytometry (FCM). RESULTS: The DNA damage in pallium neurons in rats of the fluoride group was much more serious compared with those of the control group, with the Ridit value being 0.351 and 0.639 respectively (P < 0.01) in vivo, and 0.384 4 and 0.650 1 respectively (P < 0.01) in vitro. TUNEL positive cells were found in pallium, hippocampus and cerebellar granule cells in rats of fluoride group, whereas those in the control group were rare. It was demonstrated by FCM results that the percentages of apoptotic cells both in pallium and hippocampus were significantly higher (P < 0.01) in rats of fluoride group (27.12 +/- 3.08, 34.97 +/- 5.46) than those in control group (4.63 +/- 0.98, 5.35 +/- 0.79), (P < 0.01). CONCLUSION: Sodium fluoride could induce DNA damage and apoptosis in rats brain.