摘要目的:探讨氟暴露对小鼠海马神经元细胞（HT22细胞）微小核糖核酸（microRNA，miRNA，miR）-204、脑源性神经营养因子（BDNF）、酪氨酸激酶B（TrkB）表达的影响。方法:将HT22细胞暴露于0（对照）、2、4、6、8、10 mg/L氟化钠（NaF）。培养24 h后，CCK-8法检测细胞活性，根据细胞存活率结果，选取0.0（对照）、2.5、5.0、10.0 mg/L NaF，作用于未转染和转染（加入miR-204激动剂）的HT22细胞24 h，实时荧光定量PCR（qRT-PCR）和蛋白免疫印迹（Western blot）法分别检测细胞中miR-204表达，BDNF、TrkB mRNA和蛋白表达。结果:与对照组比较，各染氟组细胞存活率降低（ P均< 0.01）。未转染细胞中，与对照组比较，miR-204表达升高（ P < 0.05或< 0.01）；5.0、10.0 mg/L染氟组BDNF mRNA表达降低（ P均< 0.01），各染毒组BDNF蛋白表达降低（ P < 0.05或< 0.01）；各染毒组TrkB mRNA表达降低（ P < 0.05或< 0.01），5.0、10.0 mg/L染氟组TrkB蛋白表达降低（ P均< 0.01）。转染细胞中，与对照组比较，各染毒组miR-204表达升高（ P均< 0.01），BDNF、TrkB mRNA和蛋白表达下降（ P均< 0.01）。细胞存活率与染氟浓度呈负相关（ r = - 0.989， P < 0.01）；染氟浓度与BDNF、TrkB mRNA、蛋白表达呈负相关（ r = - 0.746、- 0.853、- 0.889、- 0.827， P均< 0.01）；miR-204表达与染氟浓度呈正相关（ r = 0.889， P < 0.01），与BDNF、TrkB mRNA和蛋白表达呈负相关（ r = - 0.766、- 0.770，- 0.594、- 0.523， P均< 0.01）；TrkB mRNA和蛋白表达与BDNF mRNA和蛋白表达呈正相关（ r = 0.657、0.869， P均< 0.01）。 结论:氟降低HT22细胞活性，作用机制可能与上调miR-204表达后抑制了BDNF-TrkB通路有关。

abstractsObjective:To explore the changes of microRNA (miRNA, miR)-204, brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) expression levels in HT22 hippocampal neurons exposed to fluorine.Methods:The HT22 cells were exposed to NaF at 0, 2, 4, 6, 8, 10 mg/L. After 24 h, the cell viability was detected by CCK-8. According to the cell survival rate, the NaF concentrations [0.0 (control), 2.5, 5.0 and 10.0 mg/L] were selected for subsequent experiments. The infected (without transfection) and transfected (with the addition of miR-204 agonist) HT22 cells were both exposed to NaF for 24 h. The miR-204, BDNF and TrkB mRNA expression levels in cells were detected by Real time fluorescence quantitative PCR(qRT-PCR); the BDNF and TrkB protein expression levels in cells were detected by Western blotting.Results:Compared with the control group, the cell viabilities in fluorine exposure groups were decreased ( P < 0.01). In the infected groups, compared with the control group, and the miR-204 expression levels were increased ( P < 0.05 or < 0.01). The expressions of BDNF mRNA were decreased in fluorine exposure groups at 5.0 and 10.0 mg/L ( P < 0.01) and the BDNF protein expressions were decreased in all fluorine exposure groups ( P < 0.05 or < 0.01). In the exposure groups, TrkB mRNA expressions were decreased ( P < 0.05 or < 0.01). The TrkB protein expressions were decreased in fluorine exposure groups at 5.0 and 10.0 mg/L ( P < 0.01). In the transfected groups, compared with the control group, the expressions of miR-204 were increased ( P < 0.01) and the mRNA and protein expressions of BDNF and TrkB were decreased ( P < 0.01). The negative correlation was found between NaF concentration and cell survival rate ( r = - 0.989, P < 0.01). Moreover, the mRNA and protein expressions of BDNF and TrkB were negative correlated with NaF concentration ( r = - 0.746, - 0.853, - 0.889, - 0.827, P < 0.01). A positive correlation was found between NaF concentration and miR-204 expression ( r = 0.889, P < 0.01). However, the mRNA and protein expressions of BDNF and TrkB were negative correlated with miR-204 expression ( r = - 0.766, - 0.770, - 0.594, - 0.523, P < 0.01). The positive correlations were found between BDNF mRNA and protein expressions and those of TrkB ( r = 0.657, 0.869, P < 0.01). Conclusion:Fluorine has inhibited the cell activity of HT22, and the mechanism of action may be related to the inhibition of BDNF-TrkB pathway after up-regulation of miR-204 expression.