【作者】 马保华；

【导师】 史志诚； 王建华；

【作者基本信息】 西北农林科技大学 ， 临床兽医学， 2003， 博士

【摘要】 以小鼠为动物模型，研究了类二噁英多氯联苯的典型代表物质——Aroclor 1254对母鼠卵子发生、受精和附植前胚胎体内发育毒性，公鼠精子发生毒性，以及对精子受精能力和受精卵体内发育的毒性。结合卵巢和子宫、以及睾丸和附睾的组织病理学研究分析可能的毒性机理。研究采用Aroclor 1254标准品，用灭菌花生油稀释后腹腔注射染毒，染毒剂量为1／10、1／50、1／250和1／1250 LD₅₀，对照组注射花生油。给性成熟期、断奶期母鼠及公鼠染毒使其直接接触Aroclor 1254；给哺乳母鼠和妊娠母鼠染毒，使哺乳仔鼠和胎儿间接接触Aroclor 1254。 随着染毒剂量的增加，各时期接触Aroclor 1254的母鼠排卵数呈现下降的趋势，其中性成熟期和胎儿期开始接触1／10 LD₅₀ Aroclor 1254母鼠排卵数显著下降，其他各染毒组小鼠受精率与对照组无统计学差异。卵巢的组织病理学观察认为，母鼠的排卵数减少是由于卵泡发育过程中出现闭锁退化的结果。卵母细胞如能完成受精过程，大部分受精卵都能完成第一次卵裂，发育到2-细胞胚。但性成熟期和胎儿期开始接触1／10 LD₅₀ Aroclor 1254母鼠卵母细胞受精率显著下降，其他各染毒组母鼠受精率与对照组无统计学差异。Aroclor 1254毒性作用主要表现在2-细胞胚胎的进一步发育过程中，随染毒剂量的增加，胚胎发育为桑椹胚和囊胚的比率显著下降，而发育延迟胚和退化变性胚比率显著升高。其主要原因在于Aroclor 1254的直接毒性作用和生殖器官的结构异常、炎性反应及细胞的病理学变化，不能支持胚胎正常发育，使已经卵裂的2-细胞胚发育为桑椹胚和囊胚的过程中受到影响，导致发育停止或退化变性。另外，受影响母鼠胚胎发育过程中卵巢上出现卵泡发育和黄体发育受阻，可能构成胚胎发育受阻和发育中退化的部分原因。 由于Aroclor 1254的毒性作用，导致性成熟期公鼠的睾丸结构和细胞的病变，对精子发生的影响主要集中在球形精子细胞发育和精子的最后成熟过程。随着染毒剂量的增加，精子活力显著降低，畸形精子和顶体异常精子比率显著升高，而对精子密度受影响程度较小。断奶期开始接触Aroclor 1254的直接毒性作用及其导致的性腺病变，影响精母细胞的物质贮存和成熟分裂，以及球形精子细胞发育和精子最后成熟过程，使1／10 LD₅₀染毒组公鼠精子密度显著降低，而且随着染毒剂量的增加精子活力显著降低，畸形精子和顶体异常精子比率显著增加。哺乳期和胎儿期开始接触Aroclor 1254的公鼠，生殖细胞的分裂增殖和精母细胞的物质贮存障碍使进入成熟期的生殖细胞数量减少，精子密度随着染毒剂量的增加明显下降。由于经胎盘及乳汁转运到胎儿和仔鼠的Aroclor 1254的量相对较低，未造成性腺的明显病理变化，使精子形态质量受影响程度明显减小。 用性成熟期接触Aroclor 1254的公鼠与未染毒正常母鼠进行配种的研究结果表明，Aroc lor 1254对小鼠生殖毒理的研究随着公鼠染毒剂量的增加受精率和受精卵第一次卵裂率下降并延迟。在2一细胞胚的进一步发育中，仍出现发育延迟及发育退化现象，使桑堪胚和囊胚发育率显著降低。 主要结论: （1）首次系统地从性成熟期、断奶期、哺乳期和胎儿期等个体发育的不同时期开始，以不同染毒剂量使小鼠接触AroClor 1254，研究了Aroc1oI’ 1254对母鼠卵子发生、受精和附植前胚胎体内发育、以及公鼠的精子发生毒理。 （2）首次以排卵数、受精率、受精卵的第一次卵裂率、桑堪胚发育率、囊胚^孵化胚发育率、以及发育延迟胚和退化变性胚的比率，对个体发育的不同时期接触不同剂量AroClor 1254对小鼠卵子发生、受精和附植前胚胎体内发育毒性进行系统定量。证明受影响母鼠卵子发生、受精及胚胎发育毒性存在剂量一效应关系及与个体发育阶段相关的效应特点。 （3）首次以个体发育不同时期接触Aroclor 1254母鼠的卵巢、子宫的组织病理学研究结果对卵子发生、受精和附植前胚胎体内发育毒性机理进行定性。证明毒性作用与Aroclor 1254对卵泡发育和黄体成熟的干扰和对子宫组织的侵害有关。 （4）首次以输精管精子相对密度、精子活力、畸形精子比率和顶体异常精子比率，对个体发育的不同时期开始接触不同剂量Aroclor 1254对小鼠精子发生毒性进行定量。证明Aroclor 1254对精子发生的毒性存在明显的的剂量一效应关系及与个体发育阶段相关的效应特点。 （5）首次以个体发育不同时期接触AroCI叮1254公鼠的翠丸、附翠的组织病理学研究结果对对精子发生毒性机理进行定性。证明精子密度、活力及形态异常与所处性腺器官的相应病理变化有关。 （6）首次证明用接触Arodor 1254的公鼠与正常母鼠进行配种后，受精率和受精卵第一次卵裂率显著下降，胚胎正常发育率显著下降。（7）证明不同发育阶段接触AroClor1254的小鼠，在内脏器官出现组织病理学变化，并存在剂量一效应变化规律和发育时期-效应变化特点。更多还原

【Abstract】 The reproductive toxicity of Aroclor 1254 on the oogenesis, the fertilization and preimplantion embryonic in vivo in female mice, the spermatogenesis toxicity, the sperma fertilizing ability and the zygote developmental toxicity in vivo in male mice were studied, and the toxicity mechanism were discussed by histopathological examination of the ovary, the uterus, the testis and epididymides. Aroclor 1254 was diluted by sterilized peanut oil, then injected into mouse abdominal cavity, with dosages of 1/10,1/50,l/250,and 1/1250 LD50 .Mice injected the peanut oil only were used as control. The females and males in puberty and weaning period were exposure directly to Aroclor 1254; The females in lactation and pregnancy period were exposure directly to Aroclor 1254 so that the infants and the fetus were exposure indirectly to Aroclor 1254.With the increasingly of the dosages, the ovulations of the females exposure to Aroclor 1254 in every period showed a decreasing trend, the ovulation number of the females exposure to Aroclor 1254 were decreased significantly in puberty and the fetal period, between other groups and control group was no statistics difference. Histopathology observation of ovaries revealed that the ovulations decreased in females may be due to the follicular tresia. If the fertilization could be finished, a majority of the zygote can finish the first cleavage and develop into 2-cell embryo. But the fertility rate of the females exposure to Aroclor 1254 shown a marked decreased in puberty and the fetal period, between other groups and control group was no statistics difference. The toxicity effect of Aroclor 1254 behaved principally in farther development process of 2-cell embryo, the ratio of embryo development into morale and blastocysts was significantly decreased with the increasing of the dosages, but the ratio ofdevelopment relayed and degeneration embryo was significantly increased. The main reason was that the toxicity effect of Aroclor 1254 directly, and resulted in the structure anomaly,inflammation reaction and pathology transformation of the reproductive organ, so that did not enable to normal development embryo, and made development stopping or degeneration. In addition, an appearance of follicular development in ovarian and corpus luteum development relayed in influenced females, this also might made embryo development relayed and degeneration.The males in puberty were exposure to Aroclor 1254, the toxicity effect of Aroclor 1254 resulted in the structure damage and cell pathological changes of the test’s, and the toxicity effect of Aroclor 1254 on spermatogenesis focused mainly on the sphere sperm cell development and sperm maturity. With the increasing of the dosages, the sperm motility was decreased significantly. The ratio of abnormity sperm and abnormal acrosome sperm were increased significantly, and the effect on the sperm density was lower. In the mice that in the suckling period were exposure to Aroclor 1254,. the toxicity effect of Aroclor 1254 directly and resulted in the pathological changes of the sexual gland, influenced the nutrient accumulation and maturity division of the spermatocyte , the sphere sperm cell development and sperm maturity. The sperm density of the males in 1/10 LDso dosages group was decreased significantly, and with the increasing of the dosages, the sperm motility was decreased significantly, the ratio of the deformation sperm and the acrosome abnormal sperm was increased significantly. The males in the suckling and fetal period were exposure to Aroclor 1254, Aroclor 1254 disturbed the division proliferation of reproductive cell and the nutrient accumulation of the spermatocyte, so that the number of the reproductive cell in the maturation period was decreased. The sperm density was decreased significantly with the increasingly of the dosages. Owing to placenta and milk transshipping effect, the content of Aroclor 1254 in fetal and infant vivo was very low, so there were not significantly pathological changes in sexual gland, the effect of Aroclor更多还原