慢性氟暴露致小鼠海马损伤及L-型钙拮抗剂的干预作用

Hippocampal injury induced by chronic fluoride exposure and the intervention effect of L-type calcium inhibitor in mices

探讨了慢性氟暴露致小鼠海马损伤及L-型钙通道拮抗剂的干预作用.将140只初断乳ICR雄性小鼠随机分为7组:对照组(C组)、高氟组(HF组,饮用30 mg·L^-1 NaF溶液)、低氟组(LF组,饮用5 mg·L^-1 NaF溶液)、高/低氟+L-型钙通道激动剂组(FPL64176)(HF/LF+FPL)、高/低氟+L-型钙通道拮抗剂组(Nifedipine)(HF/LF+NIF).染氟6个月,染氟结束前1周,HF/LF+FPL和HF/LF+NIF组分别每天腹腔注射激动剂或拮抗剂(5 mg·kg^-1·d^-1).用TUNEL法检测小鼠海马CA1区细胞凋亡水平,用Western Blot法检测细胞膜L-型钙通道Cav1.2、Ca^2+信号通路分子和下游凋亡调节相关分子蛋白表达水平等.结果表明,与对照组比,HF/LF组小鼠海马组织抗氧化能力显著降低(p<0.05或p<0.01),细胞凋亡水平极显著上升(p<0.01),Cav1.2与Bcl-2蛋白表达水平显著下降(p<0.05或p<0.01),Ca^2+信号转导通路CaM、CaMKII和促凋亡Bax、Bax/Bcl-2蛋白表达水平显著上升(p<0.05或p<0.01).注射FPL64176的小鼠海马细胞和上述分子指标的损伤加剧,而注射NIF对海马细胞和上述分子蛋白表达有一定的逆转作用.提示L-型钙离子通道介导了氟暴露致小鼠海马损伤,氟暴露致海马细胞膜L-型钙离子通道Cav1.2蛋白、细胞内Ca^2+信号转导通路分子和下游凋亡调节相关蛋白表达异常是其分子机制之一,而L-型钙通道拮抗剂NIF可能是一种新型有效的抗氟药物.

The study aimed to investigate the hippocampal injury induced by chronic fluoride exposure and the intervention effects of L-type calcium inhibitor in mice.140 ICR male mice were randomly divided into 7 groups:control(C group),high-fluoride group(HF group,drink 30 mg·L^-1 NaF solution),low-fluoride group(LF group,drink 5 mg·L^-1 NaF solution),HF/LF+L-type calcium channel(LTCC)agonist(FPL64176)group(HF/LF+FPL group),HF/LF+LTCC inhibitor(Nifedipine)group(HF/LF+NIF group).The fluoride exposure continued for 6 months,one week before the end of fluoride exposure,each mice in HF/LF+FPL and HF/LF+NIF group was injected FPL or NIF(5 mg·kg^-1·d^-1).The apoptosis of hippocampal CA1 region cell was observed by TUNEL,and the protein expression levels of cell membrane L-calcium channel Cav1.2 and Ca^2+signaling pathway molecules,and downstream apoptosis-regulating protein related proteins were detected by Western blot.Compared with the C group,the anti-oxidation ability of hippocampus was significantly decreased(p<0.05 or p<0.01),the level of apoptosis was significantly increased(p<0.01),the protein expression level of Cav1.2,and Bcl-2 significantly decreased(p<0.05 or p<0.01),and CaM,CaMKII,Bax and Bax/Bcl-2 significantly increased(p<0.05 or p<0.01)in LF and HF group.Compared with the fluoride exposure group,FPL and NIF could aggravate or reversed the damage of hippocampal and the above-mentioned molecular proteins.In conclusion,LTCC may mediate the hippocampal injury induced by fluoride exposure in mice.The abnormal expression of the Cav1.2 protein,Ca^2+signal transduction pathway,and apoptosis-regulated proteins may be the molecular mechanisms of the fluoride induced hippocampal injury.NIF may be a new and effective anti-fluoride drug.