1.8mT不同频率正弦交变电磁场对青年大鼠峰值骨量的影响

目的 研究1.8 mT不同频率正弦交变电磁场对青年大鼠峰值骨量的影响.方法 将40只SD雌性大鼠随机分成对照组、15 Hz组、30 Hz组、50 Hz组和75 Hz组,每组8只.对照组不进行磁场处理,其余4组每天用相应频率的1.8 mT正弦交变电磁场处理90 min,于第4、6、8周进行骨密度(BMD)检测,大鼠处死后进行股骨生物力学、血清骨钙素(Osteocalcin,OC)和抗酒石酸酸性磷酸酶-5b(tartrate resistant acid phosphatase,TRAP-5b)的测定,并行双荧光间距量化分析.结果 磁场处理4周5组BMD比较差异无统计学意义(P＞0.05);处理6周15、50、75 Hz组BMD高于对照组,处理8周后50、75 Hz组BMD高于对照组(P＜0.05).处理8周后,15、50、75 Hz组大鼠股骨最大载荷和屈服强度、OC含量高于对照组,胫骨骨骺线上端两侧平均双荧光间距均大于对照组(P ＜0.05,P＜0.01).结论 50、75 Hz的1.8 mT正弦交变电磁场可有效提高青年大鼠的峰值骨量.     

不同强度三角波电磁场对大鼠骨密度和生物力学性能的影响

目的 研究不同强度三角波电磁场(TEMF)对大鼠骨密度(BMD)和生物力学性能的影响.方法 雌性SD大鼠54只随机分为6组,分别为对照组(0 mT)、0.1 mT、0.6 mT、1.2 mT、1.8 mT和2.4 mT组,每组9只.实验组每天使用TMEF干预90 min,对照组除不进行磁场干预外其他条件与实验组相同.在磁场干预第1、2、3月末腹腔麻醉测量BMD,并心脏取血处死,取离体的股骨和第4腰椎进行离体BMD检查、股骨三点弯曲和第4腰椎压缩实验.结果 电磁场干预3个月0.1 mT组全身BMD值高于对照组(P＜0.05);0.1 mT组离体股骨BMD、股骨弹性模量、最大载荷、屈服强度均高于对照组(P＜0.05);6组第4腰椎弹性模量和最大载荷比较差异无统计学意义(P＞0.05).结论 0.1 mT TMEF能够提高大鼠全身BMD和股骨BMD,但在改善生物力学性能方面的效果不明显.     

极低频电磁场对小鼠血细胞影响的实验研究

目的:观察不同照度极低频电磁场对小鼠血细胞成分的影响及淋巴细胞微核发生的关系.方法:将100只小鼠随机分为对照组和曝磁组.曝磁组小鼠分1、2、3和4四组,分别置于微机产生的极低频电磁场中,每天照射分别为20min、40min、60min、6h,对照组不接触极低频电磁场,4个月后检测各组小鼠外周血血细胞计数和淋巴细胞微核率.结果:随小鼠每天曝磁时间的增加,其血液中的RBC、WBC、PLT数量及Hb含量呈逐渐下降、淋巴细胞微核率呈逐渐增高的趋势, 中性粒细胞、嗜酸性粒细胞、单核细胞比值逐渐增高,淋巴细胞比值逐渐下降,以曝磁4组表现最为显著.RBC、Hb数量和淋巴细胞微核率与对照组结果之间存在显著性差异(P＜0.05或P＜0.01).结论:长时间接触极低频电磁场对小鼠血细胞数量和不同WBC比值存在明显的影响, 同时可诱发淋巴细胞微核的发生.     

重复测试和不同性别对小鼠旷场行为的影响

目的研究重复测试和不同性别两个因素对小鼠在旷场试验中自主行为活动和焦虑行为的影响。方法通过动物视频行为分析系统,分别记录和分析雌雄小鼠5min内在旷场中的总路程、总体平均速度、总体平行指数、中央区的路程占总路程的比例、中央区的平均速度、中央区进入次数、中央区停留时间占整体测试时间的比例和中央区平行指数,每天测试1次,共测试3d。结果在旷场试验中,小鼠的总路程、总的平均速度、总的平行指数、中央区路程占总路程的比例、中央区的平均速度、进入中央区次数、中央区停留时间和中央区的平行指数,随测试次数的增加呈下降趋势（均为P〈0．001）;整体而言,以上指标在雌雄小鼠之间无显著性差异（均为P〉0．05）,但随测试次数增加,雄性小鼠的下降趋势似乎比雌性小鼠明显,尤其在第三次测试中,雄性小鼠在中央区的平均速度（P〈0．05）和平行指数（P〈0．01）比雌性小鼠更低。结论重复测试旷场试验会影响小鼠的自主行为活动,同时也会干扰焦虑状态的评价;不同性别对小鼠的初次旷场试验测试无影响,但重复测试对雄性小鼠的自主行为活动的影响似乎比雌性小鼠更大。     

基于影像学评价正弦电磁场对大鼠股骨骨折的影响

目的 基于影像学客观评价正弦电磁场对大鼠股骨骨折愈合的影响.方法 选取SPF级Wistar雄性大鼠40只,股骨骨折模型建立成功后随机分为模型对照组和正弦电磁场治疗组,模型对照组不采取任何治疗手段,正弦电磁场治疗组每天给予50 Hz、1.8 mT电磁场治疗1.5 h,每2周对所有大鼠行X线检查观察骨折愈合情况.开始实验4...     

钙对母鼠氟暴露致仔鼠自主性活动和学习记忆的影响

目的探讨饲料钙对母鼠氟暴露致仔鼠自主性活动和学习记忆的影响。方法选用健康初断乳SD雌性大鼠75只,雄性25只,雌鼠随机分为对照组、高氟组、低钙组、低钙高氟组和高钙高氟组,饲养3个月后,雌雄鼠合笼交配产仔鼠,取14及28日龄仔鼠进行开场行为和Morris水迷宫实验。结果开场行为观测结果表明,与对比组相比,各日龄高氟组与高氟低钙组焦虑感增强,兴奋性或自发性活动能力下降,差异有统计学意义(P0.05或P0.01);水迷宫学习记忆观测结果显示,与对照组相比,各日龄高氟组与高氟低钙组学习记忆下降,差异有统计学意义(P0.05或P0.01);低钙组与高氟高钙组学习记忆改善有所改善。结论高钙饲料能明显改善母鼠氟暴露致仔鼠学习记忆的损伤,母鼠氟暴露致子代学习记忆损伤有性别差异,雌性仔鼠的损伤大于雄性仔鼠。     

极低频电磁场治疗肿瘤研究进展

极低频电磁场（Extremely low frequency electromagnetic fields，ELF—EMF）指频率为0～300Hz的交变电磁场。电场强度随电压或电势的升高而增强，磁场强度随电流的升高而增强，两者都随距离发生源的远近而迅速变化。电场很容易被建筑物遮挡，其穿透能力很弱。相比而言，磁场的穿透能力很强，即使被建筑物遮挡也不容易减弱，因此人们更关心磁场对健康的影响。     

七氟烷对小鼠学习记忆的影响

目的:观察腹腔注射七氟烷对小鼠学习记忆的影响.方法:小鼠随机分为4组(n=10):生理盐水组(NS组,ip)、七氟烷0.5 mL/kg、1.0 mL/kg、2.0 mL/kg剂量组分别用跳台法、避暗法的跳台潜伏期、步入潜伏期及错误次数,以及Y迷宫法10次测试中一次性正确次数作为评估小鼠学习记忆成绩的指标.结果:3种方法观察各组间小鼠的学习记忆成绩均无明显差异(P>0.05).结论:在本实验条件下,七氟烷对小鼠的学习记忆无明显影响.     

青风藤对吗啡成瘾小鼠学习与记忆能力的影响

目的：研究青风藤对吗啡成瘾小鼠学习与记忆能力的影响及可能机制。方法：通过Y-迷宫观察青风藤对吗啡成瘾小鼠学习与记忆能力的影响,观察海马形态研究青风藤对海马CA1区神经元的影响。结果：青风藤治疗组与吗啡戒断组小鼠的分辨学习及记忆保持能力有显著差异．小鼠海马CA1区神经元细胞数差异显著。结论：青风藤对吗啡戒断小鼠的分辨学习及记忆保持能力有极大提高．对吗啡戒断致小鼠海马CA1区神经元的损伤有一定的治疗作用。     

发育期铅染毒对大鼠学习和记忆的持续性效应

目的研究不同发育期铅染毒对大鼠学习和记忆的持续性效应。方法大鼠分别在断乳前和断乳后进行铅染毒，分别测试20、40和60天龄大鼠Y迷宫学习、短时记忆和长时记忆能力。结果(1)断乳前铅染毒组大鼠20天龄时，0、10min和24h逃避达标率显著低于对照组；停止染毒40d后，10min逃避达标率与对照组相比，差异无显著性；但0min和24h逃避达标率显著低于对照组。(2)断乳后，铅染毒组大鼠0min和24h逃避达标率显著低于对照组，24h逃避达标率显著高于断乳前铅染毒组。结论(1)断乳前铅染毒可损伤大鼠的空间学习、短时和长时记忆能力；停止染毒后短时记忆可得到恢复，而学习和长时记忆的损伤仍持续存在。(2)断乳后铅染毒可损伤大鼠的空间学习和长时记忆能力，但损伤较断乳前铅染毒轻。     

Long-term exposure to extremely low-frequency magnetic fields impairs spatial recognition memory in mice

1. In the present study, we investigated the short- and long-term effects of extremely low-frequency (ELF) magnetic fields on spatial recognition memory in mice by using a two-trial recognition Y-maze that is based on the innate tendency of rodents to explore novel environments. 2. Mice were exposed to 25 or 50 Hz electromagnetic fields for either 7 (short term) or 25 days (long term) and then tested in the Y-maze. 3. The results indicated that neither short- nor long-term exposure to magnetic fields affected the locomotor activity of mice in the Y-maze. However, long-term exposure to 50 Hz fields reduced recognition of the novel arm. 4. Our findings suggest that ELF magnetic fields impair spatial recognition memory in the Y-maze depending on the field strength and/or duration of exposure.     

Subchronic effects on leukocyte-endothelial interactions in mice by whole body exposure to extremely low frequency electromagnetic fields

Abstract. In the present study, we measured and quantified changes in leukocyte behavior in the subcutaneous microcirculation in vivo and examined serum cytokine levels in vitro while mice were exposed to continuous 50 Hz electromagnetic fields for 17 days. Mice were exposed to 50 Hz sinusoidal electromagnetic fields at magnetic densities of 0.3, 1.0 and 3.0 mT. The intramicrovascular behavior of leukocytes was evaluated by fluorescence microscopy using a dorsal skinfold chamber technique. Significantly increased endothelial-adhering leukocytes were observed only in the 3.0 mT exposure group, but no changes were detected in serum TNF-alpha and IL-1beta levels. Subsequently, long-term continuous whole body exposure to 50 Hz electromagnetic fields elicited leukocyte-endothelium interactions, however, this effect does not appear to be controlled by cytokine levels.     

The effect of extremely low frequency electromagnetic fields (ELF-EMF) on the frequency of micronuclei and sister chromatid exchange in human lymphocytes induced by benzo(a)pyrene

The interaction of extremely low frequency electromagnetic fields (ELF-EMF) on the frequency of micronuclei (MN) and sister chromatid exchange (SCE) induced by benzo(a)pyrene (BP) in human lymphocytes was examined. A 60 Hz ELF-EMF of 0.8 mT field strength was applied either alone or with the tumor initiator, BP for 24 h. The frequencies of MN and SCE induced by BP increased in a dose-dependent manner. The co-exposure of cells to BP and 0.8 mT ELF-EMF for 24 h, followed by BP exposure for 48 h led to significant increases in the frequencies of MN and SCE compared to BP treatment for 72 h alone (P<0.05), but no significant difference was observed between field exposed and sham exposed control cells. The obtained results suggest that low density ELF-EMF could act as an enhancer of the initiation process of BP rather than as an initiator of mutagenic effects in human lymphocytes.     

Acute effects of low-frequency electromagnetic fields on leukocyte-endothelial interactions in vivo

BACKGROUND: To clarify the effect of extremely low frequency electromagnetic field (ELF-EMF) on the microcirculatory system, acute effects on leukocyte-endothelium interactions resulting from ELF-EMF exposure were examined with conscious BALB/c mice by means of a dorsal skinfold chamber. MATERIALS AND METHODS: The fluorescent dye, rhodamine 6G, was injected into the caudal vein to visualize leukocytes in vivo and to analyze leukocyte-endothelium interactions. Mice were exposed in vivo to 50 Hz linear sinusoidal wave EMF at magnetic flux densities of 3, 10 or 30 mT, for 30 minutes. RESULTS: The mean velocity of free flowing leukocytes in the center stream of venules revealed no distinct changes following exposure. However, at a flux density of 30 mT, the number of adherent leukocytes, defined as the total number of rolling and endothelium-adhering leukocytes, increased significantly following ELF-EMF exposure (p<0.05); no significant differences in adherent cell numbers were found in the 3 mT and 10 mT exposure groups or sham controls comparing pre- and post-exposure periods. CONCLUSION: These results demonstrated that high magnetic flux densities of ELF-EMF had an effect on leukocyte-endothelium interactions and indicated that a threshold level for this phenomenon exists in the range of 10-30 mT under these experimental conditions.     

A comparative study on influences of static electric field and power frequency electric field on cognition in mice

Recently, electromagnetic fields around ultra-high voltage transmission lines have received considerable attentions for their potential biological effects. This study aimed to investigate the effects of static electric field (SEF) and power frequency electric field (PFEF) on cognition. Mice were exposed to SEF and PFEF with the same strength (35 kV/m) for 49 days, respectively. Behaviors in Morris water maze test and amino acid neurotransmitter levels in hippocampus were examined during exposure. Results indicated that the exposure of 35 kV/m SEF would not cause significant influences on learning and memory ability in mice, while the exposure of 35 kV/m PFEF would cause significant positive effects on learning and memory ability in mice on day 33. This difference in effects from SEF and PFEF on cognition was possibly induced by the difference in the degree of molecular polarization and ion migration in organisms under exposure of two kinds of electric fields with different frequency.     

Effect of ELF pulsed magnetic fields on survival of leukaemia-prone AKR mice

In a previous experiment an increase in the survival time of leukaemia-prone AKR mice was observed by exposure to a 600 mT or 800 mT static magnetic field when the mice were at least 200 days old. In this experiment 200-day-old-mice were exposed to a 6 mT pulsed magnetic field (PMF) for 30 minutes a day, twice a week until death. The frequency of the field was 12 Hz or 460 Hz. The exposed mice died from leukaemia but had an increased survival time; the average increase was 14.25% compared to the controls. Both the frequencies gave similar results.     

用水迷宫实验检测甲醛和乙苯联合染毒的神经毒性

目的探讨不同浓度甲醛和乙苯单独及联合染毒对小鼠神经行为的影响,分析其联合作用的类型。方法采用4×4析因设计,利用Morris水迷宫,研究甲醛(0、0.2、2.0、20.0mg/kg)、乙苯(0、50、250、500mg/kg),以及二者联合染毒对小鼠学习和记忆能力的影响。结果随着训练次数的增多,各组小鼠的逃避潜伏期呈下降趋势(P<0.05);逃避潜伏期随染毒剂量的增大而延长;染毒组的逃避潜伏期均长于阴性对照组(P<0.05),联合高剂量组的逃避潜伏期长于其他各组(P<0.05)。甲醛和乙苯单独及联合染毒均可导致小鼠第一次跨越原平台位置的时间延长(P<0.05),目标象限(Ⅳ象限)停留时间缩短(P<0.05),以及原平台象限游泳距离占总距离百分比下降(P<0.05);以上变化以联合高剂量染毒组小鼠最为突出。联合染毒对小鼠第一次跨越原平台位置的时间和原平台象限游泳距离占总距离百分比的影响存在交互作用(P<0.05)。结论甲醛和乙苯均可危害小鼠的学习和记忆能力,联合染毒组的危害程度大于单独染毒组,二者的联合效应表现为协同作用。     

参芪益元颗粒对戊巴比妥钠所致小鼠学习记忆障碍的影响

目的:研究参芪益元颗粒对戊巴比妥钠所致小鼠学习记忆障碍的影响。方法:腹腔注射戊巴比妥钠(15 mg/kg)以复制小鼠学习记忆障碍模型。50只KM小鼠随机均分为正常对照(等容生理盐水)组、模型(等容生理盐水)组、健脑补肾丸(2.00 g/kg)组与参芪益元颗粒高、低剂量(1.76、0.88 g/kg)组。采用Y型迷宫法测定小鼠正确反应次数;测定小鼠血清超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量。结果:与正常对照组比较,模型组小鼠正确反应次数减少,SOD活性减弱,MDA含量增加,差异有统计学意义(P<0.01);与模型组比较,参芪益元颗粒高、低剂量组小鼠正确反应次数增加,SOD活性增强,MDA含量减少,差异有统计学意义(P<0.01)。结论:参芪益元颗粒对戊巴比妥钠所致小鼠学习记忆障碍具有改善作用。     

督脉配穴对染铅幼年大鼠海马一氧化氮合酶阳性细胞的保护作用

目的探讨督脉配穴对染铅幼年大鼠海马不同亚区一氧化氮合酶（NOS）变化的拮抗作用。方法将40只SD大鼠随机分为3组,即对照组、染铅组、督脉配穴组。采用反映学习记忆功能的Y迷宫法测试大鼠神经行为的改变,用NADPH-黄递酶（NADPH．d）组织化学法研究大鼠海马不同亚区NOS的活性神经元变化。结果染铅组大鼠的学习记忆能力比督脉配穴组和对照组明显下降（P〈0．05）,但督脉配穴组与对照组之间差异无统计意义（P〉0．05）;组织化学实验结果显示,染铅组大鼠海马CA1区和齿状回的NOS阳性神经元明显少于督脉配穴组和对照组（P〈0．05）,在CA3区无差别,督脉配穴组与对照组各亚区之间差异无统计意义（P〉0．05）。结论铅可损伤幼年大鼠学习记忆能力,其机制可能与染铅后海马各区NOS活性的不同变化有关,督脉配穴针灸治疗对铅引起的学习记忆损伤和NOS活性的变化有拮抗作用。     

Effects of co-exposure to extremely low frequency (ELF) magnetic fields and benzene or benzene metabolites determined in vitro by the alkaline comet assay

In the present study, we investigated in vitro the possible genotoxic and/or co-genotoxic activity of 50 Hz (power frequency) magnetic fields (MF) by using the alkaline single-cell microgel-electrophoresis (comet) assay. Sets of experiments were performed to evaluate the possible interaction between 50 Hz MF and the known leukemogen benzene. Three benzene hydroxylated metabolites were also evaluated: 1,2-benzenediol (1,2-BD, catechol), 1,4-benzenediol (1,4-BD, hydroquinone), and 1,2,4-benzenetriol (1,2,4-BT). MF (1 mT) were generated by a system consisting of a pair of parallel coils in a Helmholtz configuration. To evaluate the genotoxic potential of 50 Hz MF, Jurkat cell cultures were exposed to 1 mT MF or sham-exposed for 1h. To evaluate the co-genotoxic activity of MF, the xenobiotics (benzene, catechol, hydroquinone, and 1,2,4-benzenetriol) were added to Jurkat cells subcultures at the beginning of the exposure time. In cell cultures co-exposed to 1 mT (50 Hz) MF, benzene and catechol did not show any genotoxic activity. However, co-exposure of cell cultures to 1 mT MF and hydroquinone led to the appearance of a clear genotoxic effect. Moreover, co-exposure of cell cultures to 1 mT MF and 1,2,4-benzenetriol led to a marked increase in the genotoxicity of the ultimate metabolite of benzene. The possibility that 50 Hz (power frequency) MF might interfere with the genotoxic activity of xenobiotics has important implications, since human populations are likely to be exposed to a variety of genotoxic agents concomitantly with exposure to this type of physical agent.