摘要
目的探讨氟、砷及其联合染毒对大鼠海马和大脑皮质组织Bcl-2和Bax凋亡蛋白表达的影响。方法将初断乳SPF级雄性SD大鼠按体质量随机分为对照组、氟处理组、砷处理组和氟砷联合组，每组10只。氟处理组大鼠饮用120mg／L氟化钠（NaF）水溶液，砷处理组大鼠饮用70mg／L亚砷酸钠（NaAsO2）水溶液，氟砷联合组大鼠饮用含120mg／LNaF和70mg／LNaAsO：的水溶液，对照组大鼠饮用蒸馏水。3个月后采用免疫组织化学和Westernblot法检测大鼠海马和大脑皮质组织Bcl-2和Bax凋亡蛋白的表达。结果①免疫组织化学法检测结果：大鼠海马和大脑皮质组织细胞质中Bcl-2和Bax凋亡蛋白呈现为棕黄色颗粒物；与对照组和氟、砷处理组比较，氟砷联合组大鼠海马和大脑皮质Bcl-2阳性神经元细胞数较少；与对照组比较，氟、砷处理组和氟砷联合组大鼠海马和大脑皮质Bax阳性神经元细胞数较多，尤其以氟砷联合组的阳性细胞数最多。②Westernblot法检测结果：对照组、氟处理组、砷处理组、氟砷联合组大鼠海马组织Bcl-2、Bax蛋白表达分别为0．84±O．22、0．76±0．10、0．75±0．24、0．28±0．05和0．44±0．19、0．81±0．14、1．22±0．45、1．45±0．26，其中氟砷联合组Bcl-2表达明显低于其他3组（P均〈0．05），而氟、砷处理组和氟砷联合组Bax表达均明显高于对照组（P均〈0．05），且砷处理组和氟砷联合组Bax表达高于氟处理组；上述4组大鼠大脑皮质Bcl-2、Bax蛋白表达分另U为0．51±0．18、0．50±0．12、0．49±0．19、0．33±0．19和0．39±0．18、0．79±0．30、0．79±0．35、0．80±0．18，其中氟、砷处理组和氟砷联合组大鼠Bax蛋白表达明显高于对照组（P均〈0．05）。氟、砷处理组和氟砷联合组大鼠海马和大脑皮质组织Bcl-2／Bax表达比值（0．96±0．28、0．72±0．45、0．334-0．05和O．69±0．37、0．57±0．10、0．37±0．18）均明显低于对照组（1．91±1．32、1．44±0．29，P均〈0．05），尤以氟砷联合组最明显。结论在一定染毒剂量下，氟和砷均促进大鼠海马及大脑皮质组织Bax蛋白的表达，降低海马及大脑皮质组织的Bcl-2／Bax表达比值。氟和砷对大鼠海马组织Bcl-2蛋白表达和大脑皮质组织Bcl-2／Bax蛋白表达比值的影响存在协同作用。
Objective The study was designed to explore the effects of fluoride, arsenic and co-exposure on protein expression of Bel-2 and Bax in hippocampus and cerebral cortex tissues of rats. Methods According to body weight, forty male SPF SD rats at the beginning of weaning were randomly divided into four groups. Each group was composed of 10 rats. Rats were exposed toeither 120 mg/L sodium fluoride（NaF） in fluoride treated group, 70 mg/L sodium arsenite （NaAsO2） in arsenite treated group, or 120 mg/L NaF and 70 mg/L NaAsO2 combined solution in arsenic-fluoride treated group by drinking water for 3 months, respectively. The control rats drank distilled water for 3 months. The protein expressions of Bcl-2 and Bax in hippocampus and cerebral cortex of rats were detected with immunohistochemistry and Western blotting. Results （1）The results of immunohistochemistry assay were as follows： The Bcl-2 and Bax protein in cytoplasm of hippocampus and cerebral cortex neurons appeared as brown particles. Compared with control, NaF-exposed and NaAsO2-exposed rats, the number of Bcl-2 positive neurons of hippocampus and cerebral cortex in co-exposed rats decreased. Compared with control rats, the number of Bax positive neurons of hippocampus and cerebral cortex in NaF-exposed, NaAsO2-exposed and co- exposed rats increased, especially in co-exposed rats. （~）The results of Western blotting assay were as follows： the protein expression levels of Bcl-2 and Bax in hippocampus of control, NaF-exposed, NaAsO2-exposed and co- exposed rats were 0.84 ± 0.22, 0.76 ± 0.10, 0.75 ± 0.24, 0.28 _± 0.05 and 0.44 ± 0.19, 0.81 ± 0.14, 1.22 ± 0.45, 1.45 ± 0.26, respectively. The level of Bcl-2 protein expression in hippocampus of co-exposed rats was lower than that of other three groups （all P 〈 0.05）. The levels of Bax protein expression in hippocampus in the three exposure groups were all higher than that of control rats （all P 〈 0.05）, and the levels of Bax protein expression in hippocampus of NaAsO2-exposed and co-exposed rats were higher than that of NaF-exposed rats. The protein expression levels of Bcl-2 and Bax in cerebral cortex in control, NaF-exposed, NaAsO2-exposed and co- exposed rats were 0.51 ± 0.18, 0.50 ± 0.12, 0.49 ± 0.19, 0.33 ± 0.19 and 0.39 ± 0.18, 0.79 ± 0.30, 0.79 ± 0.35, 0.80 -± 0.18, resptively. Compared with control rats, the Bax protein expressions in cerebral cortex of rats exposed to NaF, NaAsO2 and their combined solution were all higher（all P 〈 0.05）. We also found that the ratios of Bcl-2 and Bax expression in hippocampus and cerebral cortex of NaF-exposed（0.96 ± 0.28, 0.69± 0.37）, NaAsOz- exposed（0.72 ± 0.45, 0.57 ± 0.10） and co-exposed rats（0.33 ± 0.05, 0.37± 0.18） all markedly decreased than that of control rats（1.91± 1.32, 1.44 ± 0.29, all P 〈 0.05）, especially in co-exposed rats. Conclusions Under certain exposure doses, fluoride and arsenic have increased Bax protein expression, decreased Bcl-2/Bax expression ratio in hippocampus and cerebral cortex of rats. Fluoride and arsenic might have synergistic effect on Bcl-2 protein expression in hippocampus and Bcl-2/Bax expression ratio in cerebral cortex of rats.
出处
《中华地方病学杂志》
CAS
CSCD
北大核心
2013年第4期365-369,共5页
Chinese Journal of Endemiology
基金
国家自然科学基金（81102083）
