【作者】 侯旭剑；

【导师】 于素芳；

【作者基本信息】 山东大学 ， 劳动卫生与环境卫生学， 2008， 硕士

【摘要】 二甲基甲酰胺(Dimethylformamide,DMF)是一种重要的有机化工原料、农药和医药中间体,也是性能优良的溶剂和多种气体的吸附剂,广泛应用于化学纤维、皮革、染料及制药等工业生产中。随着现代工业的发展,DMF的需求量在逐年增加,职业接触DMF的工人也越来越多,DMF对工人健康的影响逐渐引起人们的重视。1948年Smyth等首先报道了DMF的毒性和职业危害,引起各国科学家对DMF毒性的关注。80年代以来我国已有数百例DMF职业中毒发生。DMF属中等毒性物质,人群对DMF的暴露是多途径的,职业环境中DMF主要经呼吸道,也可经皮肤、消化道进入体内。DMF可对全身多个器官及系统产生毒性。以往研究中,国内外大多数学者都将对DMF的研究重点放在其肝毒性上,而对生殖系统尤其是雄性生殖系统的毒作用研究较少。因此,我们就DMF对雄性生殖系统的影响进行研究,并进一步探讨其作用机制。目的:通过对雄性昆明小鼠亚慢性染毒,对小鼠的睾丸组织结构,睾丸及附睾脏器系数,精子的计数、活动度、畸形率以及睾丸酶活性、性激素的变化进行观察,探讨DMF对雄性生殖系统的影响及其作用机制,为DMF卫生标准的制定和其生殖危害的防治提供科学依据。方法:昆明小鼠40只,体重为(25±2)g,饲养条件为每天光照12h,普通饲料喂养,温度为(23±2)℃,相对湿度为(50±10)%。适应性喂养一周后,随机分为空白对照组和低、中、高三个剂量组,每组10只。染毒剂量分别为0、0.5、1和2g/kg(body weight)。每天灌胃染毒一次,连续灌胃30天。于染毒前1天对小鼠称重,以后每3天称重1次。30天后摘除眼球取血并颈椎脱臼处死。所取血液在室温下静置一小时后,置离心机中离心20分(3000pm/min),吸取上清液,-20℃保存用于测定血清睾酮(T)、黄体生成素(LH)、卵泡刺激素(FSH)水平。分离双侧睾丸和附睾,称重并计算脏器系数。每组随机抽取两个动物的一侧睾丸,放入预先配制好的中性福尔马林溶液(4%甲醛)中进行固定,用于制作病理切片,其余睾丸-80℃保存,用作睾丸琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)、酸性磷酸酶(ACP)、超氧化物歧化酶(SOD)活力及丙二醛(MDA)和睾酮(T)水平的测定。取右侧附睾用作精子活动度的测定,左侧附睾置-20℃保存,用作精子计数和精子畸形率的测定。结果:1.DMF对雄性小鼠体重、脏器重量及脏器系数的影响与对照组相比,各染毒组小鼠实验后体重显著降低(P＜0.05)。小鼠睾丸、附睾重量及睾丸脏器系数随染毒剂量增高有下降趋势。与对照组相比,2g/kg剂量组睾丸重量(P＜0.01)、附睾重量(P＜0.05)及睾丸脏器系数显著降低(P＜0.01)。2.DMF对雄性小鼠精子计数、精子活动度及精子畸形率的影响随染毒剂量的增高,精子计数及精子活动度有下降的趋势,呈剂量-效应关系,且1g/kg和2g/kg剂量组精子计数与对照组相比显著降低(P＜0.05)。精子活动度与对照组相比显著降低(P＜0.01)。各剂量组精子畸形率与对照组相比均无明显变化(P＞0.05)。3.DMF对雄性小鼠睾丸酶活力及MDA含量的影响随染毒剂量增高睾丸组织中ACP、SOD活力及MDA含量均有增高趋势,LDH、SDH活力有下降趋势。各剂量组ACP活力显著高于对照组(P＜0.01),1g/kg和2g/kg剂量组SOD活力显著高于对照组(P＜0.01),SDH活力显著低于对照组(P＜0.01),2g/kg剂量组睾丸MDA含量显著高于对照组(P＜0.01),各剂量组LDH活力显著低于对照组(P＜0.01)。4.DMF对雄性小鼠血清及睾丸组织中性激素的影响各剂量组血清LH水平与对照组相比无明显变化(P＞0.05);各剂量组血清FSH水平均高于对照组,1g/kg和2g/kg剂量组血清FSH水平显著高于对照组,(P＜0.05);各剂量组血清T和睾丸T均低于对照组,2g/kg剂量组血清T和睾丸T水平显著低于对照组(P＜0.01)。5.DMF对雄性小鼠睾丸组织结构的影响睾丸组织的病理切片显示,染毒组小鼠睾丸曲细精管明显萎缩,曲细精管中各级精母细胞减少,细胞间有中毒空泡,个别曲细精管管腔中可见脱落的生精细胞,管腔内成熟精子变少或消失。间质疏松,血管扩张。结论:1.DMF亚慢性染毒可以使小鼠睾丸及附睾重量下降,睾丸脏器系数降低。2.DMF亚慢性染毒可以引起小鼠精子计数及精子活动度下降。3.DMF亚慢性染毒能引起小鼠睾丸组织的形态改变。4.DMF亚慢性染毒会对小鼠睾丸T、血清T和血清FSH产生显著影响。5.DMF亚慢性染毒可以影响小鼠睾丸ACP、LDH、SDH、SOD的活性及MDA的含量。6.各染毒组小鼠LDH、SDH、ACP活性变化,提示DMF可能影响到睾丸的能量代谢;各染毒组小鼠SOD活性及MDA含量变化,提示DMF可能对小鼠睾丸组织产生脂质过氧化损伤;各染毒组小鼠性激素水平变化,提示DMF可能干扰小鼠的生殖内分泌功能。更多还原

【Abstract】 Dimethylformamide (DMF) is an important industrial organic material, an intermediate of pesticide and medicine as well as an excellent dissolvent and absorbent of many kinds of gases. It is widely used in fiber-making, leather-making, dye-making, medicine-making and other industrial production. With the development of modern industry, the requirement for DMF increases year by year, so are the workers who have access to DMF. More and more attention has been paid to the effects of DMF on workers’ health. The first report of toxicity and occupational hazard of DMF was from Smyth in 1984, which drew the attention of scientists all over the world. There have been hundreds of accidents of occupational hazard of DMF happened in China since 80’s. DMF is a moderate toxicant, people can be exposed to it in many ways, one of which is respiratory tract, a main path in occupational enviroment. Other paths like skin and alimentary tract are also possible for DMF to enter human body. Toxicity of DMF is multiorganic and multisystematic. Studies in the past mostly focused on hepatotoxicity of DMF, few paid attention to its reproductive toxicity, especially the male reproducitve toxicity. The present study is aiming to explore the possible effects of DMF on male reproductive system, and to further discover the possible mechanisms.ObjectiveIn order to discover the effects of DMF on male reproductive system and the possible mechanisms, as well as to provide some scientific evidences for making hygienic standards of DMF and for prevention and treatment of reproductive hazards of DMF, KM male mice were administrated subchronically. Changes of testicle tissue structure were observed, sperm counts were counted, sperm motility, abnormal sperm rate and testicle and epididymis viscera coefficient were calculated, changes of activities of testis enzymes and gonadal hormone levels were detected.Methods40 KM mice, weighted about (25±2)g. were raised. Raising conditions were sunlight 12 hours a day, temperature being (23±2)℃and relative humidity being (50±10)%. After one week raising for adaptation, all were distributed to four groups randomly, with 10 mice each group. Three out of four groups were administrated intragastricly with the dosage of 0, 0.5, 1 and 2g/kg (body weight) DMF every day separately for 30 days in a row. The rest one is as control group. All the mice were weighted at the first day of administration, and then once every three days until being sacrificed at the 30th day of administration. Before their being sacrificed, blood was obtained by pulling out their eyes. The obtained blood was kept for one hour at 20℃, and then centrifuged for 20 minutes at 3000pm/min. The upper layer of the centrifuged blood was separated and stored at -20℃for measuring serum T, LH, FSH levels. Both sides of testicles and epididymises were detached from the bodies and weighted and calculated to get viscera coefficient. Two testicles selected randomly from each group were fixed in neutral formalin solution for pathological exam. Other testicles were stored at -80℃for later measurement of enzyme activities including SDH, LDH, ACP, SOD, and contents of MDA and levels of testis T. The left side epididymises were stored at -20℃for sperm counting and determination of abnormal sperm rate, the right side epididymises were used for determination of sperm motility.Results1. Effects of DMF on body weight, viscera weight and viscera coefficient of male miceCompared with control group, mice in all trial groups show significant decrease in body weight statistically (P<0.05) after the treatment. Weights of testicles and epididymises as well as viscera coefficients of testis decrease correspondingly with the increase of administrating dosage. Compared with control group , 2g/kg group shows statistically significant decrease in testicle weight (P<0.01), epididymis weight (P<0.05) and viscera coefficient of testis (P<0.01).2. Effects of DMF on sperm counting, sperm motility and abnormal sperm rate of male miceWith the increase of administrating dosage, sperm counting and sperm motility show decreasing tendencies, which are dose-effect related. Moreover, compared with control group, sperm counts in 1g/kg group and 2g/kg group decrease statistically at 0.05 level, and sperm motilities of the two decrease statistically at 0.01 level, abnormal sperm rates among all trial groups are of no statistically significant difference (P>0.05).3. Effects of DMF on activity of testis enzyme and content of MDA of male miceWith the increase of administrating dosage, activities of ACP, SOD and contents of MDA in testes show increasing tendencies, while LDH and SDH activities are of the opposite. Compared with control group, ACP activities in all trial groups are significantly higher (P<0.01), so are SOD activities in 1g/kg and 2g/kg groups and MDA contents in 2g/kg group; SDH activities in 1g/kg and 2g/kg groups are significantly lower (P<0.01), the same as LDH activities in all trial groups.4. Effects of DMF on gonadal hormone level in serum and testis of male miceCompared with control group, serum LH levels in all trial groups show no statistical difference (P>0.05). Serum FSH levels in all trial groups are higher than control group, with Ig/kg group and 2g/kg group being statistically significant (P<0.05). T levels of both serum and testis in all trial groups are lower than control group, with 2g/kg group statistically significant (P<0.01).5. Effects of DMF on testicular tissue structure of male micePathological sections of testicular tissue show that convoluted seminiferous tubules of trial groups mice become thin, all kinds of spermatocytes in convoluted seminiferous tubules decrease in number, vacuolus can be observed in cells, some spermatogenic cells are even observed fallen into the lumens. Mature sperms in the tubules decrease in number or even completely disappear. Dilated blood capillaries and pultaceous stroma can be observed.Conclusions 1. Subchronical toxication of DMF causes decrease of testicle and epididymis weight, and viscera coefficient of male mice.2. Subchronical toxication of DMF leads to decrease of sperm count and sperm motility of male mice.3. Subchronical toxication of DMF causes morphological change in testis tissue of male mice.4. Subchronical toxication of DMF affects testis T, serum T and FSH level of male mice significantly.5. Subchronical toxication of DMF affects activity of testis enzymes including ACP, LDH, SDH, SOD, and content of MDA of male mice.6. Changes of LDH, SDH and ACP activities in all trial groups suggest that DMF might affect energy metabolism in testis tissue. Changes of SOD activity and MDA content in all trial groups suggest that DMF might cause lipid peroxidative damage to testis tissue. Changes of gonadal hormones in all trial groups suggest that DMF might interfere with reproductive endocrine system of male mice.更多还原