【作者】 周鼎伦；

【导师】 王治明；

【作者基本信息】 四川大学 ， 劳动卫生与环境卫生学， 2007， 博士

【摘要】 钒是化石燃料的主要元素之一，在石油、煤中含量较为丰富。随着近年来我国经济快速增长，能源产品消耗量也迅速增加，钒随着大量石油、煤燃烧产生的气体进入大气，由此带来的后果是人群接触机会增加以及接触人群的范围扩大，并且演化成了环境问题。同时钒作为一种重要元素广泛用于石油化工、钢铁冶炼、焊接、催化剂等领域，因此钒化合物的职业接触人群也数量巨大。神经系统对有毒有害因素最为敏感，在受到侵袭时往往首先受累，早期仅引起机体行为的变化。已有的关于钒化合物毒性的研究较少涉及这方面，尤其是缺乏人群流行病学的调查研究。本研究目的是评价钒化合物是否具有神经行为毒性及阐述其效应。论文分为三个部分，分别为人群神经行为功能测试、大鼠神经行为功能评价、病理学诊断。以下是这三个部分的结果。1．钒化合物对接触工人神经行为功能的影响采用世界卫生组织推荐的NCTB测试组合测试了193名接钒工人(接钒组)和273名非接钒工人(对照组)。接钒组和对照组调查对象性别构成没有差异，对照组文化程度高于接钒组(P＜0.05)，年龄分别为35.0±6.7岁和34.5±5.6岁、工龄分别为16.6±6.8年和14.3±6.2年。接钒组工人生产车间钒烟尘浓度总体上超过国家标准近20倍，各车间有不同，对照组工人生产车间没有检测到钒烟尘。血钒浓度测定结果显示接钒工人血钒浓度几乎都超过正常值范围，平均超标倍数在10～20倍之间。在调整了混杂因素后，NCTB情感测试结果发现接钒工人的“紧张-焦虑”、“抑郁-沮丧”、“愤怒-敌意”、“疲劳-惰性”、“困惑-迷茫”得分均高于对照组，“有力-好动”得分低于对照组，差异都具有统计学意义(P＜0.05)。说明钒化合物能增加接钒工人的消极情绪(包括紧张、抑郁、愤怒、疲劳、困惑)，降低积极情绪(有力)。以性别分类，发现钒化合物增加男性接钒工人的消极情绪，降低积极情绪；对女性只表现为降低积极情绪。以工龄分类，发现工龄＜10年，差异没有统计学意义(P＞0.05)；10年～工龄段，接钒组积极情感状态得分低于对照组，消极情感状态得分高于对照组，差异均有统计学意义(P＜0.05)；20年～工龄段，接钒组积极情感状态得分低于对照组，差异有统计学意义(P＜0.05)，消极情感状态得分差异没有统计学意义。神经行为方面，接钒组和对照组最快反应时和平均反应时差异没有统计学意义(P＞0.05)；数字广度上，顺序得分要高于对照组，差异有显著性(P＜0.05)，倒序低于对照组，差异没有显著性(P＞0.05)；圣地安娜提转敏捷度方面，无论是习惯手或非习惯手，接钒组的得分均低于对照组，且差异有统计学意义(P＜0.05)；接钒组数字译码和视觉保留得分均低于对照组，差异有统计学意义(P＜0.05)；目标追踪方面，接钒组正确点数低于对照组，错误点数高于对照组，准确率也低于对照组，差异均具有统计学意义(P＜0.05)。分性别比较，男性较女性敏感，表现在圣地安娜提转敏捷度、数字译码、视觉保留、目标追踪等指标，均是男性接钒组和对照组比较，差异有统计学意义，而女性没有统计学意义。分工龄比较，多数指标在10～年工龄段表现出差异。说明不同的神经行为功能效应对钒化合物的敏感程度不一样，而且，受调查对象的年龄影响。对钒化合物越敏感的指标，出现时间越早，而随着年龄的增长，钒化合物的损伤效应受年龄增长的退化效应干扰而变得不明显。采用因子分析方法，提取了7个公因子。其分析结果与神经行为功能的多元分析结果是一致的。2．偏钒酸钠对大鼠神经行为功能的影响将受试大鼠分为偏钒酸钠高、中、低剂量组，同时设阳性对照组(氯化锰)和空白对照组(蒸馏水)，采用灌胃染毒的方式染毒30天。所有大鼠均做开阔场实验、转棒实验和水迷宫实验，主要反应大鼠认知能力、运动活力和运动协调能力。一共测试4次，分别为第0天(灌胃前)、第30天(灌胃结束)、第40天(灌胃停止后10天)、第50天(灌胃停止后20天)。实验表明偏钒酸钠具有胃肠道毒性和呼吸道毒性，表现为：①灌胃结束时只存活65只大鼠，另外25只大鼠死亡，其原因主要为上述两种毒性反应；②偏钒酸钠染毒组(尤其是高剂量组)大鼠体重较空白对照组低。神经行为功能评价结果发现：①偏钒酸钠染毒致使大鼠行走格子数下降，有随偏钒酸钠浓度升高而格子数减少的趋势，但直立次数变化不显著；②在棒上的停留时间，低剂量组与空白对照组时间差异不大，中剂量组与阳性对照组时间接近，说明偏钒酸钠可导致大鼠运动协调能力下降；③记忆力方面，偏钒酸钠各剂量组到达终点的时间与对照组比较没有表现出显著差异，错误次数方面，偏钒酸钠各剂量组次数较对照组高，而且中剂量组的大鼠错误次数与氯化锰组较接近。3．偏钒酸钠染毒大鼠脑组织病理学检查在灌胃结束后的第30天，分别从中剂量组、低剂量组、阳性对照组、空白对照组随机抽取10只大鼠做病理切片，高剂量组只剩下4只，全部处死做病理切片。切片位置为大鼠脑组织正中矢状面，包括脑干、小脑和海马，重点观察这三个部位有无病理学改变。病理切片结果显示，所有大鼠的脑干、小脑及脑干均未见明显病变。尽管切片中可见脑膜灶性或小片状出血、脑膜增厚、室管膜下胶质细胞增生、大脑皮质星形胶质细胞增生、胶质囊肿等病变类型，但病变周围均无炎性反应，且不同剂量组之间没有表现出明显差异，故认为偏钒酸钠灌胃30天还不能引起海马、小脑及脑干部位出现病理性改变。综上，在日常生活环境中钒负荷越来越高，以及接触钒化合物的职业人群数量庞大的背景下，评价钒化合物是否具有神经行为功能及其效应有较强的实际意义。本文全面系统地研究了钒化合物的神经毒性，探讨了职业人群神经行为的变化，积累了人群流行病学调查资料。通过对钒化合物的神经行为毒性进行了综合性评价(即人群神经行为功能变化、大鼠行为改变和大鼠脑组织病理学诊断)，认为钒化合物具有神经行为毒性，损害神经系统后表现出的效应跟接触者的性别和接触时间有关。具体的效应为：①钒化合物可增加接钒工人的消极情绪(包括紧张、抑郁、愤怒、疲劳和困惑)，降低接钒工人的积极情绪(有力)；②动物实验和人群流行病学调查均表明钒化合物可降低运动协调性：③钒化合物对短期记忆能力的影响还不明确，需做进一步的研究。更多还原

【Abstract】 Vanadium is one of the main chemical elements of fossil fuel and is abundant in petroleum and coal. In recent years along with China’s fast growing economy, consumption of energy products increases quickly. Vanadium enters into the atmosphere with gas produced by the burning of much petroleum and coal, thus renders all people exposed in increasing vanadium burden. At the same time, vanadium is widely used in petroleum chemical engineering, steel smelting, welding and catalyst...etc. as an important chemical element. Therefore the number of occupational people who are exposed to vanadium compound is quite huge.The nervous system is the most sensitive to poisonous or hazardous factors and usually is the first organ to be injured when one is exposed to those factors, causing the body’s behavior change in early days. Many researches concerning the toxicity of vanadium compound have no involved this aspect, and there is especially lack of epidemiological study. This research aims to evaluate whether vanadium compound has toxicity to neurobehavioral effect and elaborate its effect characteristic. The thesis is divided into three parts: test on neurobehavioral function among people; evaluation on neurobehavioral function among rats; pathological diagnosis. The following is the results of these three parts. 1. Vanadium compound’s influence on neurobehavioral function among workers exposed to vanadiumWe adopted the NCTB (Neurobehavioral Core Test Battery) recommended by the World Health Organization and tested 193 workers exposed to vanadium (exposed group) and 273 workers unexposed (control group). There was no statistically significant difference between two groups in gender distribution. Educational background in the control group was higher than that in the exposed group (P<0.05). For the average age, there is no significant differences between two groups, respectively 35.9 + 6.7 in exposed group and 34.5 + 5.6 in control group. Also there is no significant differences for work duation, respectively 16.6 + 6.8 in exposed group and 14.3 + 6.2 in control group. Vanadium dust density in the exposed group’s workshops exceeded the occupational exposure limit for nearly 20 times in general, with some differences among each workshop. There was no vanadium dust tested in the control group’s workshops. Blood vanadium density test showed that almost all blood vanadium densities of exposed workers exceeded occupational exposure limit about 10-20 times averagely.After adjusting mixing factors, the NCTB emotion test results showed that workers exposed to vanadium got higher scores than control group workers in "Tension-anxiety", "Depress-dejection", "Anger-hostility", "Fatigue-inertia", "Confusion-bewilderment", while they got lower scores in "Vigor-activity", with all differences statistically significant (P<0.05). The results indicated that the vanadium compound increased the negative motion (including anxiety, depression, anger, fatigue, confusion) in workers exposed to vanadium, and decreased the positive motion (activity). After splitting the data according to gender, the results displayed that vanadium compound increased negative motion and decreased positive motion in male workers exposed to vanadium, while in female it only decreased positive motion. After splitting the data according to work duration, the results displayed that among workers less than 10 years, there was no statistically significant difference; among those between 10 and 20 years, vanadium compound increased negative motion and decreased positive motion in exposed group and the differences were statistically significant (P<0.05); among those over 20 years, vanadium compound increased negative motion in exposed group and the difference was statistically significant (P<0.05) while there was no statistically significant difference in scores of negative emotion between two groups.As to neurobehavioral, there were no statistically significant differences in simple reaction time between two groups (P>0.05); As to digit span, the exposed group got a higher scores in forward and a lower scores in backword with no statistically significant differences (P>0.05); As to Santa Ana, the exposed group got a lower scores either with habitual or non-habitual hand and the difference was statistically significant (P<0.05); as for digit symbol and Benton visual retention, the exposed group got lower scores and the differences were statistically significant (P<0.05); as to pursuit aiming, the exposed group got less right points , more wrong points as well as a lower exactness rate than the control group and the differences were statistically significant (P<0.05). After splitting the data according to gender, we found that male workers were more sensitive than females, as the differences were statistically significant (P<0.05) in indexes of Santa Ana, digit symbol, Benton visual retention, pursuit aiming etc. in male workers from two groups, while there was no statistically significant differences in female workers. After splitting the data according to work duration, we found that most indexes had statistically significant differences in workers between 10 and 19 years. The results indicated that the sensitivity of different nerve behavior functions to vanadium compound varied, and was influenced by workers’ age. The more sensitive indexes were, the earlier these functions change appeared. Yet along with the growth of age, the harm effect of vanadium compound decreased because of the aging effect interference.We extracted 7 main compositions using the Main Composition Analysis method. Its analytical results were in accordance with the multivariate analysis results of nerve behavior function.2. Sodium metavanadate’s influence upon the neurobehavioral function of ratsThe exposed rats were divided into three dose groups: high dose, medium dose and low dose. At the same time we adopted a positive control group (manganese chloride) and blank control group (distilled water). All rats were made by intragastric administration for 30 days. Then all rats finished three tests, including Open Field Test, Rotarod and Maze experiment, mainly reflecting cognition ability, sport vitality and sport coordinate ability. Totally we did tests for 4 times, respectively on the 0 days (before stomach infusion), 30 days (just after stomach infusion), 40 days (10 days after stomach infusion) and 50 days (0 days after stomach infusion).Experiments indicated that sodium metavanadate showed a toxicity to gastrointestinal and respiratory, which was reflected as follows:①Only 65 rats survived, and 25 rats died. The main reasons for death might the two kinds of toxicity mentioned above;②Rats in sodium metavanadate group (especially in the high dose group) had lower weight than those in blank control group.Results of the neurobehavioral function evaluation showed:①As to the rats exposed to sodium metavanadate, the higher dose they were exposed to, the less lattices they could walk through. But there were not so much differences in the times for straighten;②There were not too many differences between results of rats in the low dose group and that of rats in the blank control group, while results of rats in the high dose group was similar to that of rats in the positive control group. This results indicted that sodium metavanadate could decrease the rats’s coordinate ability ?When it came to memory, there was not much difference in the time it took rats to arrive at the end between each exposed group and their corresponding control group. As to times of mistakes, it was higher in each exposed group than that in their corresponding control group. The times of mistakes in medium and high dose groups were close to that in manganese chloride groups.3. Pathology test to rat brain tissue exposed to sodium metavanadateOn the 30th days after intragastric administration, 30 rats were chosed randomly with each 10 from medium dose group, low dose group, positive control group and blank control group respectively as samples for pathologic section. All the 4 rats survived in the high dose group were killed for pathologic section. The position is median sagittal plane of brain, including cerebrum, cerebellum and hippocampus. We mainly concerned whether there were any pathologic changes in these three parts.The pathologic section results showed that there were no significant pathological changes in the cerebrum, cerebellum, hippocampus and brain stem in all rats. Though there are some changes found in section, such as hemorrhage and thickening in meninges, proliferation of gliocyte cell in hypoependyma, proliferation of horizontal cell in brain mantle, cyst, etc. No inflammation was found nearby pathologic parts, and the difference wasn’t statistically significant in groups. As a result, we thought sodium metavanadate wouldn’t cause pathological changes in the brain, cerebellums and brain stems.In general, as the vanadium burden keeps rising in our daily environment and the number of occupational workers exposed to vanadium is quite huge, it is practically meaningful to evaluate whether vanadium compound has toxicity to neurobehavioral function and its effect characteristics. This thesis studied the nerve toxicity comprehensively and systematically. It explored the neurobehavioral changes in occupational group and accumulated epidemiological data. After a comprehensive evaluation on vanadium compound’s neurobehavioral toxicity (including neurobehavioral changes among people, behavior changes of rats and brain pathology test of rat), we concluded that vanadium compound had neurobehavioral toxicity, and the effect characteristics were relative with gender and time of exposure. The specific effect characteristics included:①vanadium compound can increase the negative motion (including anxiety, depression, anger, fatigue, confusion) and decrease the positive motion (activity) in workers exposed to vanadium.②both animal experiment and epidemiological investigation indicated that vanadium compound can lower the coordination ability;③it is not sure that vanadium compound might decrease short-term memory and further research is needed.更多还原