【摘要】 选取6 ind健康的雄性俄罗斯鲟(Acipenser gueldenstaedti),经人工催产后获得成熟的精子,运用扫描电镜和透射电镜,观察了超低温冷冻前后精子的形态结构。结果显示,经过超低温冷冻后精子形态结构发生了较大变化,其中冻精顶体长度、头中部宽度及中段宽度与鲜精相比显著增加(P<0.05);中段长度及后外侧延伸物与鲜精相比显著减少(P<0.05)。冻后有38.6%的精子在形态结构上受到不同程度的损伤。精子的结构损伤主要表现在精子顶体不明显或与核发生糅合,后外侧延伸物消失,甚至顶体脱落;精子核膜皱褶,泡状化,膜与核之间空隙加大,有的部分甚至出现膜断裂,核内内切沟模糊;精子中段发生膨大和变形,线粒体外膜破损,线粒体条状嵴结构弥散,线粒体脱落;鞭毛外鳍褶与鞭毛脱离,鞭毛与中段脱离,少数鞭毛在中段断开。结果表明,超低温冷冻对精子的损伤主要集中在膜系统,中心粒等微管系统基本完好。更多还原

【Abstract】 To deeply understand the effects of cryopreservation on the configuration of spermatozoa,we chose Acipenser gueldenstaedti as the object,and observed the exterior shapes and interior structure of spermatozoa by means of scanning electron microscope and transmission electron microscope.The adults of Acipenser gueldenstaedti were collected from Qiandao Lake,Zhejiang Province,China,the males were aged 7.The average length was 91.5-112.6 cm and average weight was 4.52-6.34 kg.Six mature males were selected to extract uncontaminated spermatozoa from abdomen.Sperm motility was estimated using a microscope,samples with above 90% of motile spermatozoa were used to study.Native semens were diluted 1∶1 with 23.4 mM sucrose+0.25 mM KCl+30 mM Tris(p H 8.0) and addition 10% glycol as cryoprotectants,the samples were plunged in 250 μL plastic centrifuge tube,samples were equilibrated for 20 min at 4 ℃,then equilibrated for 1 min at -20℃,and preserved in liquid nitrogen,the samples were thawed in 38℃ bath before determination.Fresh and frozen spermatozoa were fixed with 2.5% glutaraldehyde,then the samples were observed by electron microscope.The sperm morphology and ultrastructure changed greatly after cryopreservation.The length of acrosome,the width of middle head and midpiece increased significantly(P<0.05),the length of midpiece and posterolateral projections became shorter,there were significant differences between fresh and thawed sperm(P<0.05).About 38.6% of the sperms were damaged after cryopreservation.The ultrastructure exhibition of cryodamage focused on the following aspects:the acrosome was not obvious or the acrosome mixed with nuclear,the posterolateral projections disappeared even the acrosome lost.The nuclear membrane of sperm folded and vacuolated,the gap between the membrane and the nucleus increased,membranes broke in some parts and interweaving endonuclear canals was unclear.The midpiece of sperm enlarged and deformed,mitochondrial outer membrane broke,mitochondrial stripe ridge structure dispersed and even mitochondria dropped,posterolateral fin of flagellum released from flagellum,the flagellum detached from midpiece,a few flagellas were disconnected in the middle.更多还原