5-Bromo-2'-deoxyuridine labeling:historical perspectives,factors infiuencing the detection,toxicity,and its implications in the neurogenesis

The halopyrimidine 5-bromo-2′-deoxyuridine(BrdU)is an exogenous marker of DNA synthesis.Since the introduction of monoclonal antibodies against BrdU,an increasing number of methodologies have been used for the immunodetection of this synthesized bromine-tagged base analogue into replicating DNA.BrdU labeling is widely used for identifying neuron precursors and following their fate during the embryonic,perinatal,and adult neurogenesis in a variety of vertebrate species including birds,reptiles,and mammals.Due to BrdU toxicity,its incorporation into replicating DNA presents adverse consequences on the generation,survival,and settled patterns of cells.This may lead to false results and misinterpretation in the identification of proliferative neuroblasts.In this review,I will indicate the detrimental effects of this nucleoside during the development of the central nervous system,as well as the reliability of BrdU labeling to detect proliferating neuroblasts.Moreover,it will show factors influencing BrdU immunodetection and the contribution of this nucleoside to the study of prenatal,perinatal,and adult neurogenesis.Human adult neurogenesis will also be discussed.It is my hope that this review serves as a reference for those researchers who focused on detecting cells that are in the synthetic phase of the cell cycle.

Fe^(2+)/Mn^(2+)活化亚硫酸盐降解盐酸土霉素的机理研究

盐酸土霉素常被用于治疗畜禽疾病,但是它不能被畜禽完全代谢,残留的盐酸土霉素进入水体危害水环境的健康。铁锰作为常见的过渡金属,通常以二价态活化亚硫酸盐来降解有机污染物,反应条件温和、操作简单,但是单独的二价铁与二价锰氧化还原电势低,活化亚硫酸盐效果较差。本研究采用Fe^(2+)/Mn^(2+)共活化Na_(2)SO_(3)降解水中的盐酸土霉素,考察药剂用量、pH、溶解氧、氯离子、碳酸根及腐殖酸对Fe^(2+)/Mn^(2+)/Na_(2)SO_(3)体系降解盐酸土霉素的影响;通过焦磷酸盐实验、自由基淬灭实验和EPR实验分析Fe^(2+)/Mn^(2+)/Na_(2)SO_(3)体系中的活性物种;利用紫外可见光谱、傅里叶红外光谱、气相色谱-质谱联用仪识别盐酸土霉素的官能团及其降解中间产物的变化,推断盐酸土霉素的降解途径。结果表明:当Fe^(2+)/Mn^(2+)/Na_(2)SO_(3)浓度比为1∶4∶20(浓度分别为0.1、0.4和2 mmol/L)时,在反应45 min、pH为9.0条件下,盐酸土霉素的去除率和矿化率最高,分别达到94%和49%。随着溶解氧从9 mg/L下降至1.89 mg/L,盐酸土霉素去除率从94%下降至17%;氯离子、腐殖酸和碳酸根均对盐酸土霉素的降解产生抑制作用。Mn(Ⅲ)和SO_(4)·^(-)是降解盐酸土霉素的主要活性氧化剂,盐酸土霉素的降解经过电子转移、开环与酰基化等过程。

电协同Fe^(2+)活化过硫酸盐处理偶氮染料废水的研究

偶氮染料废水会对自然环境和人类健康产生巨大危害。文章研究电协同Fe^(2+)活化过硫酸盐体系高效处理偶氮染料废水,以金橙G废水为处理对象,考察不同反应条件例如pH、Fe^(2+)投加量、过二硫酸盐(PDS)投加量、电流密度等因素对处理效果的影响,采用响应曲面法优化反应条件并确定最佳反应条件下的处理效果。结果表明,在pH为3、极板间距为9 cm、电流密度为15 mA/cm^(2)、PDS投加量为6.66 mmol/L、Fe^(2+)投加量为2 mmol/L、Na_(2)SO_(4)投加量为89.39 mmol/L的条件下,金橙G废水色度平均去除率为93.03%,COD平均去除率为85.80%。分析电协同Fe^(2+)活化过硫酸盐体系起主要作用的自由基及降解机理,证实了电和Fe^(2+)的协同作用。该研究可为电协同Fe^(2+)活化过硫酸盐体系在偶氮染料废水处理领域的应用提供技术支撑。

Toxicity Effect of Hg^(2+) and Cr(VI) on Alga Growth in Eutrophic Water

[ Objective] The toxicity effect of Hg^2＋ and Cr（Ⅵ） on alga growth in eutrophic water was studied to provide reference for biomonitoring and bioremediation of eutrophic water. [ Method ] The mother liquid of alga, which was separated from the eutrophic water, were put into the solutions of Hg^2＋ and Cr（Ⅵ） with different concentrations and their mixture solution, respectively. And the toxicity effect of Hg^2＋ and Cr（Ⅵ） on the growth and propagation of alga in eutrophic water was observed. [ Result] The alga in eutrophic water performed rather sensitive to Cr（Ⅵ） and when its concentration was over 1 mg/L, threre was obvious effect on alga growth. The alga was not very sensitive to Hg^2＋ when its concentration was lower, but its toxicity became stronger and stronger when its concentration increased to some extent and the toxicity effect of Cr（Ⅵ） on alga growth was just on the contrary. When the ion concentration was lower than 10 mg/L, the toxicity of Hg^2＋ on alga was lower than that of Cr（Ⅵ）. When the concentration was over 10 mg/L, the toxicity of Hg^2＋ exceeded that of Cr（Ⅵ）. The toxicity of ion mixture solution of Hg^2＋ and Cr（Ⅵ） had synergism inhibition on alga, which could be performed only when the concentration was over 4 mg/L. [ Conclusion] The toxicity of heavy metal on alga not only related to the alga cell, but also related to the concentration of heavy metal ion.

Fe^(2+)、Cu^(2+)诱导工艺对柞木表板颜色变化规律的影响

木材中的木质素、抽提物等物质具有能与金属盐溶液产生颜色反应的特性。利用这一特性以硫酸亚铁、硫酸铜溶液作为诱导剂,通过正交试验得到色差最大时的工艺参数,探究金属Fe^(2+)、Cu^(2+)的诱导剂质量分数、诱导时间、干燥时间、干燥温度对实木复合地板柞木表板颜色变化的影响。结果表明:Fe^(2+)、Cu^(2+)的诱导剂质量分数对柞木表板色彩色调的影响极为显著(F值分别为20.4453、8.8442);柞木表板的明度色品指数(L^(*))、红绿轴色品指数(a^(*))、黄蓝轴色品指数(b^(*))均随着Fe^(2+)、Cu^(2+)的诱导剂质量分数、诱导时间、干燥时间的增加而逐渐减少,总色差(ΔE^(*))逐渐增大,最大为31.53、9.90,表板色调逐渐偏暗、偏绿、偏蓝;随着干燥温度的增加,Fe^(2+)、Cu^(2+)诱导时的柞木表板总色差都逐渐减小。

外源Fe^(2+)浓度和矿物粒径对生物浸铀的影响

为改善以往生物浸铀效率不高的缺陷,通过添加外源Fe^(2+)及改变矿物粒径来提高生物对铀的浸出率。研究结果表明:外源Fe^(2+)浓度分别为0、0.5、1.0和2.0 g/L时,铀浸出率分别为87.34%、88.27%、91.23%、89.13%,当浸出体系中Fe^(2+)浓度为1.0 g/L时,铀矿石会产生部分溶解且表面粗糙孔隙明显,有利于铀的浸出,溶浸液中存在适量的Fe^(2+)对生物浸铀的能力具有提升效果。另外,外源Fe^(2+)对铀矿生物浸出符合固体产物层控制模型,浸出过程主要受扩散控制。当粒径<-2 mm和-5 mm时铀浸出率分别为91.23%和83.70%,矿物粒径适当减小可增大颗粒比表面积,同样利于铀的浸出。

Fe^(2+)螯合剂对羟脯氨酸发酵的影响

为解决反式-4-羟基脯氨酸发酵过程中Fe^(2+)供应不足、产酸效率低等问题。该研究以大肠杆菌HYP-08为供试菌株,首先通过单因素实验探究Fe^(2+)螯合剂种类及添加量对羟脯氨酸发酵生产的影响,并通过5 L发酵放大验证,以羟脯氨酸产量、生物量,糖酸转化率为指标,进一步探究其在放大过程中的影响,结果表明葡萄糖酸亚铁对羟脯氨酸发酵效果最好,流加发酵生产中,最终确定了10 h开始持连续流加的补料方式,反式-4-羟基脯氨酸生物量及产量达到最高,分别为146.2、118.6 g/L,较优化前提高了12.1%和4.2%,副产物乙酸减少到1.05 g/L,葡萄糖酸亚铁的添加有效增强了菌体活力,提高了羟脯氨酸的产量和糖酸转化率,为微生物发酵生产羟脯氨酸提供了依据。

Ferrostatin-1 protects HT-22 cells from oxidative toxicity

Ferroptosis is a type of programmed cell death dependent on iron.It is different from other forms of cell death such as apoptosis,classic necrosis and autophagy.Ferroptosis is involved in many neurodegenerative diseases.The role of ferroptosis in glutamate-induced neuronal toxicity is not fully understood.To test its toxicity,glutamate(1.25–20 mM)was applied to HT-22 cells for 12 to 48 hours.The optimal experimental conditions occurred at 12 hours after incubation with 5 mM glutamate.Cells were cultured with 3–12μM ferrostatin-1,an inhibitor of ferroptosis,for 12 hours before exposure to glutamate.The cell viability was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Autophagy was determined by monodansylcadaverine staining and apoptosis by caspase 3 activity.Damage to cell structures was observed under light and by transmission electron microscopy.The release of lactate dehydrogenase was detected by the commercial kit.Reactive oxygen species were measured by flow cytometry.Glutathione peroxidase activity,superoxide dismutase activity and malondialdehyde level were detected by the appropriate commercial kit.Prostaglandin peroxidase synthase 2 and glutathione peroxidase 4 gene expression was detected by real-time quantitative polymerase chain reaction.Glutathione peroxidase 4 and nuclear factor erythroid-derived-like 2 protein expression was detected by western blot analysis.Results showed that ferrostatin-1 can significantly counter the effects of glutamate on HT-22 cells,improving the survival rate,reducing the release of lactate dehydrogenase and reducing the damage to mitochondrial ultrastructure.However,it did not affect the caspase-3 expression and monodansylcadaverine-positive staining in glutamate-injured HT-22 cells.Ferrostatin-1 reduced the levels of reactive oxygen species and malondialdehyde and enhanced superoxide dismutase activity.It decreased gene expression of prostaglandin peroxidase synthase 2 and increased gene expression of glutathione peroxidase 4 and protein expressions of glutathione peroxidase 4 and nuclear factor(erythroid-derived)-like 2 in glutamate-injured HT-22 cells.Treatment of cultured cells with the apoptosis inhibitor Z-Val-Ala-Asp(OMe)-fluoromethyl ketone(2–8μM),autophagy inhibitor 3-methyladenine(100–400μM)or necrosis inhibitor necrostatin-1(10–40μM)had no effect on glutamate induced cell damage.However,the iron chelator deferoxamine mesylate salt inhibited glutamate induced cell death.Thus,the results suggested that ferroptosis is caused by glutamate-induced toxicity and that ferrostatin-1 protects HT-22 cells from glutamate-induced oxidative toxicity by inhibiting the oxidative stress.

以研促教:利用荧光探针检测Fe^(2+)的实验设计

本文以荧光探针的设计合成和监测亚铁离子(Fe^(2+))应用于分析化学拓展实验教学为主题,介绍了一种新型的荧光探针DCM-Fe,其通过引入N-氧化物基团有效抑制了分子内电荷转移的发生,实现了对Fe^(2+)荧光“turn on”型检测。本文还阐述了在实验教学中,通过本实验的设计和实施,学生可以深入理解荧光探针的设计合成原理和荧光检测技术的应用,在实践中掌握荧光探针的合成、分析和应用,并培养了学生的实验技能和创新意识。本实验教学可为分析化学实验教学的拓展提供一种新思路和方法。

Acute Toxicity of Clethodim, Cypermethrin and 2,4-D-butylate to the Larva of Chironomus sinicus

[Objective] The aim of this study was to detect the acute toxicity of clethodim, cypermethrin and 2,4-D-butylate. [Method] Chironomus sinicus larvae were exposed to different concentrations of clethodim, cypermethrin and 2,4-D-butylate. Survival rate, lethal concentration 50 （LC50） and superoxide dismutase （SOD） activity in the homogenate of the larvae were monitored to detect the toxicity of the pesti- cides. [Result] The survival rates of C. sinicus larvae exposed to cypermethrin and 2,4-D-butylate for 12 h were almost unchanged at different concentrations, but de- creased with concentration increasing 48 h later. For each pesticide, the differences in survival rates of C. sinicus larvae at 48 h were significant. The 48 h LC50 of clethodim, cypermethrin and 2,4-D-butylate to C. sinicus larvae were 1.842, 0.150 and 1.999 mg/L, respectively. The acute toxicity of cypermethrin was the highest a- mong the three pesticides and that of 2,4-D-butylate was the lowest. Clethodim sig- nificantly reduced the SOD content in a dose-dependent manner. 2,4-D-butylate also reduced SOD content in C. sinicus larvae, but the reduction was not significantly re- lated to its dosage. However, cypermethrin showed no significant effect on SOD ac- tivity in C. sinicus larvae.

Comparison of T-2 Toxin and HT-2 Toxin Distributed in the Skeletal System with That in Other Tissues of Rats by Acute Toxicity Test

Twelve healthy rats were divided into the T-2 toxin group receiving gavage of 1 mg/kg T-2 toxin and the control group receiving gavage of normal saline. Total relative concentrations of T-2 toxin and HT-2 toxin in the skeletal system（thighbone, knee joints, and costal cartilage） were significantly higher than those in the heart, liver, and kidneys（P 〈 0.05）. The relative concentrations of T-2 toxin and HT-2 toxin in the skeletal system（thighbone and costal cartilage） were also significantly higher than those in the heart, liver, and kidneys. The rats administered T-2 toxin showed rapid metabolism compared with that in rats administered HT-2 toxin, and the metabolic conversion rates in the different tissues were 68.20%-90.70%.

Glycerin Monostearate Aggravates Male Reproductive Toxicity Caused by Di(2-ethylhexyl)Phthalate in Rats

Human beings are increasingly exposed to phthalates,which are a group of chemicals used to make plastics more flexible and harder to break,and simultaneously ingesting abundant food emulsifiers via daily diet.The purpose of this study was to investigate the effect of the food emulsifier glycerin monostearate(GMS)on male reproductive toxicity caused by di(2-ethylhexyl)phthalate(DEHP,one of the phthalates)and explore the underlying mechanism.Thirty male Sprague-Dawley rats were randomly divided into control group,DEHP group and DEHP+GMS group.Rats in the DEHP group and DEHP+GMS group were orally administered with 200 mg/kg/d DEHP with or without 20 mg/kg/d GMS.After 30 days of continuous intervention,it was found that the serum testosterone level was significantly lowered in DEHP group and DEHP+GMS group than that in control group(P<0.01).The serum testosterone level and the relative testis weight were significantly decreased in the DEHP+GMS group as compared with those in the DEHP group and control group(P<0.05).More spermatids were observed to be shed off in DEHP+GMS group than in DEHP group.The expression levels of cell cycle checkpoint kinase 1(Chkl),cell division cycle gene 2(Cdc2),and cyclin-dependent kinase 2(CDK2)were down-regulated in DEHP group,and this tendency was more significant in DEHP+GMS group(P<0.05 or P<0.01).There was no significant difference in the P-glycoprotein(P-gp)expression between DEHP group and control group.However,P-gp was markedly down-regulated in DEHP+GMS group(P<O.Ol).The results indicated that the food emulsifier GMS aggravated the toxicity of DEHP on male reproduction by inhibiting the cell cycle of testicular cells and the expression of P-gp in testis tissues.

营养液不同浓度Fe^(2+)对水培小白菜生长发育及品质的影响

为筛选适宜水培小白菜生长的Fe^(2+)浓度,该文以苏州青为试验材料,开展了不同浓度Fe^(2+)对小白菜生长发育及品质的影响试验。试验结果表明,水培营养液Fe^(2+)浓度为0.03 mmol/L处理,水培小白菜株高、茎粗均显著高于其他处理,地上部鲜质量、地上部干质量、地下部鲜质量、地下部干质量最大,较对照分别提高92.5%、266.7%、115.5%、357.9%,叶绿素含量(57.12 mg/g)、维生素C含量[92.15 mg/(100 g)]、可溶性糖含量(0.43%)最高,较对照分别提高77.67%、50.44%、30.30%,小白菜丙二醛含量最低(11.06 nmol/g),较对照降低39.33%。综上,营养液Fe2+浓度为0.03 mmol/L时,水培小白菜生长势最旺、品质最佳、抗逆性最强。

Melanophore Indexing:A New Bio-assay Technique for the Analysis of Acute Heavy Metal (HgCl_2) Toxicity

Toxicity of 0.3 ppm (96 h LC50 value) and 0.03 ppm of mercuric chloride on the melanophores of the skin at different time intervals has been studied. Mercury treatment causes immediate increase in the number and size of the pigment cells. Subsequently these pigment cells form a dense matting of melanophore network with their cell processes intellacing with those of their neighbours. These cells later show degeneration and lysis releasing large quantity of pigment granules into the intercellular spaces in the dermis.Later the pigment cells regenerate several times each followed by degeneration in a cyclic manner. Prolonged treatment with subletha. concentration of mercuric chloride does not show significant alteration in the melanophore density and size. Statistical analysis and wide spread destruction of melanophores observed during 4-6 days of exPosure might help in testing water samples contaminated with lethal concentration of heavy metal salts

甲基磺酸盐电镀液中Fe^(2+)质量浓度对镀锡板的影响

采用扫描电镜(SEM)、X射线衍射(XRD)、塔费尔曲线及循环伏安曲线等测试方法,研究了在甲基磺酸盐体系镀锡工艺中,Fe^(2+)质量浓度对镀锡板的耐蚀性、电镀过程中Sn^(2+)扩散系数及电流效率的影响.结果表明:Fe^(2+)质量浓度增加会导致镀锡板表面孔隙数量增多,抑制镀层中的锡粒向(200)晶面生长,致使镀锡板耐蚀性下降,当Fe^(2+)质量浓度超过8.0 g/L时,镀锡板耐蚀性明显降低;同时,Fe^(2+)质量浓度增加会导致电镀锡过程中Sn^(2+)扩散系数减小、电流效率降低.

不同因素对Fe^(3+)-TiO_(2)/ACF降解NH_(3)的影响

为了探究不同因素对Fe^(3+)-TiO_(2)/活性炭纤维(ACF)降解氨气(NH_(3))的影响规律,采用Fe^(3+)-TiO_(2)/ACF复合材料,以NH_(3)为目标降解物,研究初始浓度、流速、光催化剂负载量以及光照强度对Fe^(3+)-TiO_(2)/ACF降解NH_(3)的影响,并进行了相应的反应动力学分析。结果表明:随着初始浓度的增加,NH_(3)降解率呈现略微降低的趋势,光催化过程基本符合L-H一级反应动力学模型;随着流速的增加,NH_(3)降解率表现为先升高后降低,其光催化过程也基本符合L-H一级反应动力学模型;随着光催化剂负载量以及光照强度的增加,NH_(3)降解率表现为略微增加的趋势。

Studies on the testicular toxicity of 2-bromopropane,an environmental endocrine disrupter

Aim: 2-bromopropane (2-BP) is known as an environmentalendocrine disrupter. Recently its reproductive and hematopoitic tox-icity has aroused the attention of the toxicologists. The presentstudy was designed to study its testicular toxicity in male rats.Methods; Forty male SD rats were divided into four groups of10 rats each. 2-BP was administered intraperitoneally at doses of1800 mg, 600 mg or 200 mg per kg body weight per day for 5days. The control rats were given a similar volume of the vehicle.The animals were sacrificed two days after the last dose. Results: With increasing doses, the seminiferous tubular damage wasgradually increased and the percentage of spermatogonia in the totalgerm cells gradually decreased ( P < 0. 05). The seminiferoustubular area of rats taking 1800 mg/kg was also reduced significant-ly . The body weight, testicular weight and relative testicular weightof rats taking the highest dose level were all significantly decreasedas compared with the controls. (Reprod Contracep 2001; 21; 157-60)

Acute Toxicity and Cardio-Respiratory Effects of 2-Deoxy-D-Glucose: A Promising Radio Sensitiser

Objective To evaluate the acute toxicity of 2-deoxy-D-glucose （2DG） by oral （p.o.） and intravenous （i.v.） routes, and also the cardio-respiratory effects following high doses of 2DG in animal models. Methods The LD50 of 2DG （in water） was determined in rats and mice by p.o. route and in mice by i.v. route. The effect of 2-DG （250 mg/kg, 500 mg/kg, and 1000 mg/kg, i.v.） was studied on various cardio-respiratory parameters viz., mean arterial blood pressure, heart rate and respiratory rate in anaesthetised rats. The effect of 2DG （500 mg/kg, 1000 mg/kg, and 2000 mg/kg, p.o.） was also studied on various respiratory parameters viz., respiratory rate and tidal volume in conscious rats and mice using a computer program. Results The p.o. LD50 of 2DG was found to be 〉8000 mg/kg in mice and rats, and at this dose no death was observed. The LD50 in mice by i.v. route was found to be 8000 mg/kg. At this dose 2 out of 4 mice died and the death occurred within 6 h. A significant increase in the body weight was observed after p.o. administration of 2DG in rats at 500 mg/kg, 1000 mg/kg, and 2000 mg/kg doses. There was no significant change in the body weight at 4000 mg/kg and 8000 mg/kg by the p.o. route in rats and up to 8000 mg/kg by p.o. as well as i.v. routes in mice. Intravenous administration of 2DG （250 mg/kg, 500 mg/kg, and 1000 mg/kg） in anaesthetised rats showed a time-dependent decrease in the mean arterial blood pressure. There was no change in the heart rate in any of the treatment groups. The tidal volume was not changed significantly by p.o administration in conscious rats, but a significant decrease in the respiratory frequency at 500 mg/kg and 1000 mg/kg doses was observed. In the mice also there was no change in the tidal volume after p.o, administration, but the respiratory frequency decreased significantly at 2000 mg/kg dose. Conclusion 2DG is a safe compound but can cause a fall in the blood pressure and a decrease in respiratory frequency at high doses.

Aquatic toxicity of di (2-eihylhexyl) phthalate to duckweeds

This study is concerned with the effects of di （2-ethylhexyl） phthalate （DEHP） on two kinds of duckweeds （Spirodela polyrhiza and Lemna minor）.The results indicate that DEHP has aquatic toxicity to Spirodela polyrhiza at 0.4 mg/L and to Lemna minor at over 0.1 mg/L by changing their physiologic-biochemical characteristics.The contents of duckweed chlorophyll and soluble protein decrease with increasing DEHP concentration after 7 d of exposure.DEHP shows the stimulating role in catalase （CAT） and superoxide dismutase （SOD） systems at relative low levels.At 0.01 mg/L and 0.005 mg/L,SOD activities of Spirodela polyrhiza and Lemna minor reach their peak values respectively,while CAT activity reaches its maximum value at 0.05 mg/L and 0.01 mg/L.When DEHP levels are too high,the protection enzyme system would be destroyed and plant growth is inhibited.The analysis of malondialdehyde （MDA） and Fourier transform infrared spectroscopy manifest that DEHP could affect the tested duckweeds by destroying its cell membranes,and Spirodela polyrhiza is more resistant to DEHP exposure than Lemna minor.

Study on Testicular Toxicity of 2-Bromopropane, an Environmental Endocrine Disrupter

2-Bromopropane (2-BP) is considered as a kind of environmental endocrine disrupters (EDs). Its reproductive and hematopoietic toxicity has aroused the attention of international toxicologists during the past five years.In the present study, we aimed to determine experimentally the testicular toxicity of 2-BP in male rats. Materials & Methods Forty SD male rats were divided into four groups of 10 rats each. The rats were intra-abdominally administered 2-BP once per day for 5 days continuously at the doses of 1800 mg/kg, 600 mg/kg, 200 mg/kg and normal saline, respectively. The rats were dissected one week after the first administration. Results The body weight, absolute testes weight and relative testes weight of the rats in 1 800 mg/kg dose group decreased significantly with comparison to those of the con- trol group,while the weight of accessory gonads showed no significant change. With the increase of dosage, the seminiferous tubules damage rate aggravated while the ratio of spermatogonia in total germ cells fell with P<0. 05. The seminiferous tubule area of rats in 1800 mg/kg group also reduced significantly. Under light microscopic examination, the spermatogonia of administered rats showed degeneration and chro- matin condensation. The nucleus of spermatocytes appeared hyperchromatic and py- knotic.Obvious testicular damage could be found in rats of high dose group, including large amount of spermatogonia necrosis or loss and reduced spermatocyte number. The electron microscopic findings were similar to those of the light microscopy, except that typical morphological change was found in the middle dose group: the structure of spermatogonia was destroyed, mitochondrion and endoplasmic reticulum scattered outside, nucleus disintegrated; some of the spermatocytes' membrane became nuclear, chromatin condensed and cogulation necrosis appeared; the nuclear membrane of round spermatids also showed slight damage. Conclusion The results indicated that testis was the target organ of 2-BP's reproduc- tive toxicity. The testicular toxicity of 2-BP started from damaging spermatogonia and its damage on spermatogonia was most obvious among all germ cells.