燃煤污染型氟中毒大鼠脑组织NOS活性及NO含量改变

Changes of brain tissue NOS activity and NO content in rats with coalburning fluorosis

目的探讨燃煤型氟中毒对大鼠脑组织一氧化氮合酶(NOS)活性及一氧化氮(NO)含量影响。方法24只SD大鼠随机分为3组,对照组、低、高氟组。染氟组以地氟病区燃煤烘烤的玉米为主要饲料,复制氟中毒动物模型,6个月后用氟离子选择电极法检测动物尿及脑氟含量,比色法测定脑组织NOS活性,硝酸还原酶法测定脑组织NO含量。结果染氟6个月时,低、高氟组大鼠尿氟为(2.87±0.12)、(5.27±0.15)mg/L,脑氟为(1.14±0.04)、(1.79±0.04)mg/kg,明显高于对照组[尿氟(1.68±0.02)mg/L,脑氟(0.52±0.05)mg/kg],差异有统计学意义(P<0.05);低氟组大鼠脑组织白细胞/巨噬细胞性NOS(iNOS)活性[(8.04±3.90)k U/g]与低、高氟组大鼠脑组织中NO含量[分别为(3.13±0.63)、(4.25±0.66)μmol/L]明显高于对照组[iNOS活性(4.02±0.20)k U/g、NO含量(2.29±0.46)μmol/L],差异有统计学意义(P<0.05)。结论饲喂燃煤型氟中毒病区燃煤烘烤的饲料可致大鼠氟中毒,导致大鼠脑组织中iNOS活性及NO含量升高。

Objective To observe the influence of coal-burning fiuorosis on activity of nitric oxide synthase （NOS） and content of nitric oxide （NO） in rat brain tissue. Methods Twenty-four Sprague-Dawley （SD） rats were randomly divided into a control group and low- and high-fluoride exposure groups. The rats in low- and nigh-fluoride exposure groups were fed for 6 months continuously with the corn polluted during drying process due to the burning of high fluoride coal from endemic fluorosis areas to establish an animal fluorosis model. By the end of the treatment, fluoride contents in urine and brain tissue of the rats were detected with fluorine ion selective electrode;NOS activities were determined with photometric method and NO contents were measured with nitrate reductase method. Results Compared with the control rats, the rats exposed to low- and high-fluoride exhibited significantly higher fluoride content in urine （2. 87 ± 0. 12 and 5.27 ±0. 15 vs. 1.68 ±0.02 mg/L） and brain tissues （ 1.14 ±0. 04 and 1.79 ±0. 04 vs. 0. 52 ±0. 05 mg/kg） and significantly nigher NO content in brain tissues （3. 13 ±03 and 4. 25 ±0. 66 vs. 2. 29 ±0. 46 μmol/L） （P 〈0. 05 for all）. The activity of inducible NOS （iNOS） in brain tissues of the rats with low-fluoride exposure was significantly nigher than that of the control rats （ 8. 04 ± 3.90 vs. 4.02 ± 0. 20 kU/g） （ P 〈 0.05 ）. Conclusion Chronic fluorosis could be induced in rats fed with the corn polluted during drying process by burning of high fluoride coal from endemic fluorosis areas and iNOS activity and NO content in brain tissues could increase in the rats with coal-burning fluorosis.