燃煤型氟中毒大鼠海马区组织病理学分析

目的 复制燃煤型氟中毒大鼠模型并观察其对海马CA1区形态学影响.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、骨及脑氟含量,观察大鼠海马CA1区神经元病理变化,用Biornias2000图象分析系统测试大鼠海马CA1区神经元胞体平均面积、周长及平均灰度值.结果 低、高氟组大鼠尿氟为(2.87 ±0.12)、(5.27±0.15)mg/L,骨氟(2 912±140)、(4 624±20) mg/kg,脑氟(1.14±0.04)、( 1.79 ±0.04) mg/kg;与对照组尿氟(1.68±0.02)mg/L、骨氟(1479±127) mg/kg、脑氟(0.52±0.05) mg/kg比较,差异有统计学意义(P＜0.05或P＜0.01);尼氏染色显示,与对照组大鼠神经元平均灰度值( 115±4)比较,染氟组大鼠均明显增加[低氟(157±7),高氟(164±8)].结论 长期食用燃煤型氟中毒病区燃煤烘烤的粮食可以引起氟中毒;并导致动物尿、骨、脑氟含量增高,使大鼠海马CA1区神经元蛋白合成功能下降.     

燃煤型氟中毒大鼠脑组织神经型尼古丁受体mRNA及蛋白表达水平改变

目的 观察燃煤型氟中毒大鼠学习记忆能力变化,测定大鼠脑组织神经型尼古丁受体(nAChR)mRNA和蛋白表达水平,探讨大鼠学习记忆能力改变的发生机制.方法 健康SD大鼠24只,体质量100～120 g,按体质量随机分为3组,每组8只.对照组饲以常规饲料,低氟组和高氟组以燃煤型氟中毒重病区燃煤烘烤的当地玉米为主要饲料(含氟量分别为11.30、104.20 mg/kg)来复制慢性氟中毒大鼠模型,染氟时间为6个月.染氟结束后,用Morris水迷宫方法检测大鼠行为学变化,处死动物取脑,用匀浆-氟离子选择电极法测定脑组织含氟量,实时荧光定量PCR法检测nAChR mRNA水平,蛋白印迹法测定nAChR蛋白表达水平.结果 低氟组和高氟组大鼠逃避潜伏期时间[(12.42±8.03)、(17.48±8.05)s]较对照组[(7.04±3.29)s]显著延长(P均<0.05),高氟组第7天穿过平台次数[(1.62±0.87)次]和逗留平台象限时间[(16.70±5.02)s]较对照组[(3.53±1.67)次、(23.33±5.35)s]降低(P均<0.05).低氟组和高氟组大鼠脑组织含氟量[(1.14±0.04)、(1.79±0.04)mg/kg]显著高于对照组[(0.52±0.05)mg/kg,P均<0.05],且高氟组大鼠脑组织含氟量高于低氟组(P<0.05).高氟组大鼠脑组织nAChR α3、α4、α7亚单位mRNA水平(1.51±0.20、1.45±0.06、1.63±0.08)较对照组(1.79±0.11、1.66±0.14、1.83±0.06)显著降低(P均<0.05),而低氟组(1.65±0.17、1.59±0.09、1.71±0.03)与对照组比较无明显改变(P均>0.05).低氟组和高氟组大鼠脑组织nAChR α3、α4、α7亚单位蛋白表达水平(0.58±0.13、0.16±0.03、1.41±0.38和0.56±0.23、0.08±0.02、0.51±0.16)较对照组(1.48±0.42、0.57±0.21、2.56±0.26)显著降低(P<0.05或<0.01).结论 燃煤型氟中毒大鼠学习记忆能力降低可能与脑组织nAChR蛋白表达及mRNA水平降低有关,nAChR表达改变可能是引起动物学习记忆能力降低的主要机制.

Abstract：

Objective To observe the learning and memory changes in coal-burning type of fluorosis rats, detect the expressions of neuronal nicotinic acetylcholine receptor(nAChR) at mRNA and protein levels in rat brains and to reveal the mechanism of changed learning and memory ability. Methods Twenty-four healthy SD rats, weighting 100 - 120 g, were randomly divided into three groups(8 in each). Control group was fed with normal diet, and low- and high-dose fluoride groups were fed with corn polluted with high fluoride (fluoride were 11.30,104.20 mg/kg, respectively) during drying processes with local burning-coal from the areas of endemic fluorosis to established rat model of chronic fluorosis. After exposed to fluoride for 6 months, behavioral changes were measured by Morris water maze. Animals were sacrificed, the brain was taken, after homogenizing the fluoride content of brain tissue was determined by fluoride ion selective electrode. The α3, α4 and α7 nAChR subunits at mRNA and protein levels were analyzed by real-time PCR and Western blotting, respectively. Results For rats in low- and high-fluoride groups, the escape latency time[(12.42 ± 8.03),(17.48 ± 8.05)s] was significantly longer than that in the control[(7.04 ± 3.29)s, all P< 0.05]. For rats in high-fluoride group, the numbers of crossing the platforms (1.62 ± 0.87) and the time of staying at the platforms[(16.70 ± 5.02)s] were significantly decreased as compared to that of control[3.53 ± 1.67, (23.33 ± 5.35)s, all P < 0.05]. The fluoride content in rat brain tissue in low- or high-fluoride groups [(1.14 ± 0.04), (1.79 ± 0.04)mg/kg] was significantly higher than that of control [ (0.52 ± 0.05) mg/kg, all P < 0.05]; in addition, the amount of fluoride in brain tissue of high-fluoride group was significantly higher than that of low-fluoride group(P < 0.05). In high-fluoride group, the mRNA expressions of α3, α4 and α7 nAChR subunits in rat brains(1.51 ± 0.20,1.45 ± 0.06,1.63 ± 0.08) were significantly lower as compared to controls (1.79 ± 0.11,1.66 ± 0.14,1.83 ± 0.06, all P< 0.05); whereas there were no significant changes in mRNA levels of these receptor subunits of the rat brains between low-fluoride group(1.65 ± 0.17,1.59 ± 0.09,1.71 ± 0.03) and controls (all P > 0.05). Furthermore, the protein levels of α3, α4 and α7 nAChR subunits in rat brains of highfluoride group(0.58 ± 0.13,0.16 ± 0.03,1.41 ± 0.38) and low-fluoride group(0.56 ± 0.23,0.08 ± 0.02,0.51 ± 0.16) were significantly lower than those of controls( 1.48 ± 0.42,0.57 ± 0.21,2.56 ± 0.26, P<0.05 or < 0.01). Conclusions Decreased ability of learning and memory in coal-burning type of fluorosis rats may be associated with declined expressions of nAChR at proteins and mRNA levels, which might be the main mechanism of the behavior change.     

燃煤型氟中毒对大鼠脑组织NO含量及NOS mRNA和蛋白表达的影响

目的观察燃煤型氟中毒对大鼠脑组织NO含量及NOS mRNA和蛋白表达的影响。方法健康SD大鼠24只,体质量100～120 g,按体质量随机分为3组,每组8只。对照组饲以常规饲料,低氟组和高氟组以氟病区燃煤烘烤的玉米为主要饲料(含氟量分别为11.30、104.20 mg/kg),来复制氟中毒大鼠模型,染氟时间为3个月。用氟离子选择电极法检测动物尿氟、骨氟、脑氟含量,观察大鼠海马CA1区神经元病理变化,用Biomias 2000图像分析系统测试大鼠海马CA1区神经元胞体平均面积、周长及平均灰度值,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,蛋白印迹方法测定NOS蛋白水平;实时荧光定量PCR方法测定NOS mRNA水平。结果低、高氟组大鼠尿氟为(2.61±0.11)(4.39±0.13) mg/L,骨氟(2 734±137)(4 323±203) mg/kg,脑氟(1.00±0.08)(1.14±0.02) mg/kg;与对照组尿氟(1.59±0.10) mg/L、骨氟(1 399±152) mg/kg、脑氟(0.41±0.06) mg/kg比较,差异有统计学意义(P0.05或P0.01);尼氏染色显示,与对照组大鼠神经元平均灰度值(119.0±9.7)比较,染氟组大鼠均明显增加[低氟(153.0±8.9),高氟(159.4±2.9)];低氟组、高氟组大鼠脑组织总NOS活性[(8.57±2.40)、(11.49±3.10) kU/g]较对照组(16.80±3.20) kU/g显著性下降(P0.05),高氟组大鼠脑组织NO含量(2.05±0.25)μmol/L较对照组(4.68±1.78)μmol/L显著性降低(P0.05)。低氟组、高氟组大鼠脑组织NOS蛋白表达水平[(0.53±0.24),(0.82±0.28)]较对照组(0.17±0.02)显著增加(P0.05/0.01),低氟组、高氟组大鼠脑组织NOS mRNA水平[(1.37±0.07),(1.38±0.08)]均较对照组(1.53±0.17)显著下降(P0.05)。结论低剂量氟具有一定神经毒性,表现为食用燃煤型氟中毒病区燃煤烘烤的粮食低剂量、早期可导致动物脑氟含量增高,使大鼠海马CA1区神经元蛋白合成功能下降,脑组织NOS活性、NO含量、NOS蛋白及mRNA表达改变。     

燃煤污染型氟中毒大鼠学习记忆能力及胆碱酯酶活性改变

目的 观察燃煤污染型氟中毒大鼠学习记忆能力的变化,探讨其发生机制.方法 健康SD大鼠48只,按染氟剂量分为对照、低氟、高氟3组.低氟组、高氟组大鼠以燃煤型地方病氟中毒重病区燃煤烘烤的当地玉米为主要饲料,复制氟中毒大鼠模型,实验期为3、6个月,各8只大鼠.实验结束时用Morris水迷宫方法检测大鼠行为学变化,并用比色法测定脑组织乙酰胆碱酯酶和丁酰胆碱酯酶活性.结果 染氟剂量对逃避潜伏期时间、第7天穿过平台次数、逗留平台象限时间有明显影响(F值分别为29.29、6.47、6.50,P均<0.01):染氟时间对第7天穿过平台次数和逗留平台象限时间有明显影响(F值分别为16.11、45.59,P均<0.01);染氟剂量和时间对第7天穿过平台次数和逗留平台象限时间有交互作用(F值分别为4.67、5.68,P<0.05或<0.01).3个月时,高氟组大鼠逃避潜伏期时间[(14.71±4.85)s]较对照组[(9.28±4.22)s]明显增加(P<0.05);6个月时,低氟组、高氟组大鼠逃避潜伏期时间[(12.42±8.03)、(17.48±8.05)s]较对照组[(7.04±3.29)s]延长(P均<0.05),高氟组第7天穿过平台次数[(1.62±0.87)次]和逗留平台象限时间[(16.70±5.02)s]较对照组[(3.53±1.67)次、(23.33±5.35)s]降低(P均<0.05).染氟剂量对乙酰胆碱酯酶与丁酰胆碱酯酶活性均有明显影响(F值分别为12.83、13.27,P均<0.01);染氟时间对丁酰胆碱酯酶活性有明显影响(F=16.26,P<0.01).3个月时,低氟组丁酰胆碱酯酶活性[(0.55±0.12)kU/g]明显低于对照组[(0.73±0.10)kU/g,P<0.05],高氟组乙酰胆碱酯酶[(0.62±0.42)kU/g]和丁酰胆碱酯酶活性[(0.58±0.10)kU/g]均明显低于对照组[(1.41±0.52)、(0.73±0.10)kU/g,P均<0.05].胆碱酯酶活性与逃避潜伏期时间呈负相关(r=-0.68,P<0.01),胆碱酯酶活性与逗留平台象限时间呈正相关(r=0.57,P<0.01).结论 燃煤污染型慢性氟中毒大鼠学习记忆能力减退,可能与脑组织胆碱酯酶活性下降有关,二者间有量效关系.     

氟中毒对仔鼠学习记忆及脑胆碱酯酶活性影响

目的探讨粮食污染造成的氟中毒对仔鼠学习记忆影响及其作用机制。方法SD大鼠随机分为对照组、高氟组。高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,饲养6个月后,取雌雄合笼后生产的30 d龄仔鼠,采用Morris水迷宫方法检测仔鼠行为学变化,应用生物化学方法测定脑组织胆碱酯酶活性。结果高氟组仔鼠逃避潜伏期时间为(9.242±5.852)s,与对照组仔鼠(4.948±2.698)s比较,明显延长(P0.01);高氟组仔鼠第7d穿过平台次数和逗留平台象限时间分别为(3.040±1.968)次,(23.070±5.427)s,与对照组仔鼠比较,均明显降低(P0.05,P0.01);高氟组仔鼠脑组织中胆碱酯酶活性明显低于对照组(P0.01);胆碱酯酶活性与逃避潜伏期呈负相关,与第7 d穿过平台次数和逗留平台象限时间呈正相关。结论过量氟可引起仔鼠空间学习记忆能力降低,其机制可能与脑组织胆碱酯酶活性下降有关。     

燃煤污染型氟中毒大鼠脑组织ERK/p-90RSK信号转导通路研究

目的复制燃煤污染型氟中毒大鼠模型,检测其细胞外信号调节激酶/90ku核小体S6激酶(ERK/p-90RSK)信号通路的变化,探讨燃煤污染型氟中毒中枢神经系统损害的发病机制。方法以贵州省地方性燃煤污染型氟中毒重病区燃煤烘烤的玉米为主要饲料,复制不同摄氟剂量的慢性氟中毒大鼠模型,实验期为6个月。Western-blotting法检测ERK/p-90RSK信号通路相关磷酸化蛋白的表达水平。结果成功建造燃煤污染型氟中毒大鼠模型。检测结果显示,染氟组中大鼠脑组织中p-ERK1/2和p-90RSK蛋白的表达均高于对照组,且高剂量染氟组高于低剂量染氟组,差异有统计学意义(P<0.05)。结论燃煤污染型氟中毒可引起大鼠脑组织中ERK信号转导通路的过度激活,而p-90RSK的激活可能是氟中毒大鼠的反馈性保护机制。     

燃煤污染型氟中毒大鼠学习记忆能力及胆碱酯酶活性改变

Objective To observe the influence of coal burning fluorosis on learning and memory ability in rats and reveal its possible mechanisms. Methods Healthy 48 SD rats were divided into control, low-fluoride and high-fluoride group. All rats in fluoride exposed groups were fed with the eom polluted by drying processes with burning coal containing high level of fluoride obtained from the endemic fluorosis area to produce the animal model of fluorosis. The experiment period were 3,6 mouths, respectively. The ability of leaning and memory was measured by Morris test and cholinesterase activity detected by photometric method at 3 or 6 month after experiment, respectively. Results Fluoride contents signifieantlly influenced the escape latency, the numbers of crossing the platforms and the time of staying the platforms(the value of F was 29.29,6.47,6.50, respectively, P<0.01).In addition, the numbers of crossing the platforms and the time of staying the platforms were influenced by the exposed time(the value of F was 16.11,45.59, P<0.01). Furthermore, the fluoride contents and the exposed time had an interaction between the numbers of crossing the platforms and the time of staying the platforms (the value of F was 4.67,5.68, P<0.05 or<0.01). Three months after the experiment, the mean values of escape latency [(14.71± 4.85)s] of rats in highly fluoride exposed group were significantly prolonged as compared with controls [(9.28±4.22)s]; 6 month after the experiment, the mean values of escape latency[(12.42±8.03)s, (17.48± 8.05)s] of rats in both groups exposed to fluoride were significantly prolonged as compared to controls [(7.04± 3.29)s, P<0.05]. The decreased numbers of crossing the platforms[(1.62±0.87)number] and the declined time of staying the platforms[(16.70±5.02)s] were found in the rats exposed to high fluoride as compared to controls [(3.53±1.67 )number, (23.33±5.35)s, P<0.05]. The fluoride contents obviously influenced the activities of acetylcholinesterase and butylcolinesterase (the value of F was 12.83,13.27, P<0.01). On the other hand, the times of breeding also influnced the activities of butylcolinesterase (the value of F was 16.26, P<0.01). In 3 months of the experiment, the activities of butylcolinesterase [(0.55±0.12)kU/g] in low fluoride exposed group were significantly decreased in comparison with controls[(0.73±0.10)kU/g, P<0.05]. The activities of acetylcholinesterase[(0.62±0.42)kU/g] and butylcolioesterase[(0.58±0.10)kU/g] in high fluoride group were significantly decreased as compared to eontrois[(1.41±0.52), (0.73±0.10)kU/g, P<0.05]. The correlation analysis showed that there was a negative correlation between the cholinesterase and the escape latency(r=-0.68, P< 0.01), and a positive correlation between the cholinesterase and the time of staying the platforms(r=0.57, P< 0.01). Conclusions The ability of learning and memory in rats with coal buring fluorosis was decreased, which might be connected to the decreased activity of cholinesterase in a dose-effect correlation.     

慢性氟中毒脑损伤机制探讨

慢性氟中毒是一种严重危害人类健康的地球化学性疾病,长期摄入过多的氟除了引起氟骨症和氟斑牙外,还可造成其他系统的损害[1].氟能透过血脑屏障蓄积在脑组织,影响大脑神经细胞的形态和功能[2-3].近年来,人们较为关注的是地方性氟中毒病区患者识认功能改变和病区儿童智力降低的情况,有关慢性氟中毒脑损伤的机制较为复杂,主要有以下几个方面的认识.     

P27^KIP1、P21^WAF1、Bax在胃肠道间质瘤中的表达及临床意义

目的：探讨P27^KIP1、P21^WAF1和Bax在胃肠道间质瘤中的表达及其与临床生物学行为的相关性。方法采用免疫组化法检测P27^KIP1、P21^WAF1和Bax在胃肠道间质瘤中的阳性表达情况,并在良性组、潜在恶性组、恶性病例组之间进行比较。结果55例胃肠道间质瘤中,P27^KIP1、P21^WAF1和Bax的阳性表达率分别为36.3%、54.5%、60%。P21WAF1、Bax在良性组的表达分别为21.4%、28.6%,而在潜在恶性组、恶性组明显增高。P27KIP1在良性组的表达率为64.3%,明显高于潜在恶性组、恶性组（21.4%、29.6%）。P27^KIP1、P21^WAF1和Bax三者在潜在恶性组、恶性组的表达与良性组比较差异有统计学意义,而潜在恶性组与恶性组之间差异无统计学意义。P27^KIP1、P21^WAF1和Bax的表达与胃肠道间质瘤患者的性别、年龄、部位、肿瘤大小、有无坏死、组织学分型无关,而与其恶性潜能分级相关。结论 P27KIP1的低表达、P21WAF1和Bax的高表达与胃肠道间质瘤临床恶性潜能密切相关。