中缅树鼩精子形态特征及冷冻损伤

Morphological characteristics and cryodamage of Chinese tree shrew(Tupaia belangeri chinensis) sperm

树鼩作为一种新型的、接近灵长类的实验动物,在医学生物学上的应用受到越来越多的重视。精子的结构特性研究及冷冻后结构的完整性分析是精子生物学的主要内容,也有助于树鼩的实验室快速繁殖。该研究采用人工饲养的中缅树鼩(Tupaia belangeri chinensis),结果显示其睾丸占总体重的(1.05±0.07)%,总体积为(1.12±0.10)mL。附睾尾及输精管精子总量估计在2.2×107～8.8×107,其运动度和顶体完整率分别为(68.8±3.9)%和(90.0±2.1)%。利用扫描电子显微镜和透射电子显微镜对树鼩附睾精子的超微结构进行的观察和分析显示精子头部呈圆形或卵圆形;头部长度、宽度平均分别为6.65和5.82μm;精子尾部中段、主段、尾段和精子总长度平均分别为13.39、52.35、65.74和73.05μm;尾部中段的线粒体螺旋数量为48个,其轴丝结构为典型的"9+9+2"结构。冷冻解冻后的精子主要表现在顶体与质膜不完整、精子断裂、尾部扭曲和膨大。上述结果提示树鼩精子与其他哺乳动物精子的结构特征相似,但是精子大小和线粒体螺旋数目有明显的差别,且超微结构改变仍是冷冻精子运动和受精能力下降的主要原因。

The tree shrew（Tupaia belangeri chinensis） is a small non-rodent mammal,which is a relatively new experimental animal in medicine due to its close evolutionary relationship to primates and its rapid propagation.Sperm characteristics and cryopreservation in the tree shrew were the main contents of our spermatological research.Epididymal sperm were surgically harvested from male tree shrews captured from the Kunming area.The rate of testis weight to body weight was（1.05±0.07）%,volume of both testis was（1.12±0.10） mL,total sperm from epididymis and vas deferens were 2.2？8.8×107,and sperm motility and acrosome integrity were（68.8±3.9）% and（90.0±2.1）%,respectively.Sperm ultrastructure of the tree shrew was examined by scanning electron microscopy and transmission electron microscopy.Tree shrew sperm had a round or oval shaped head of approximately 6.65×5.82 μm,and midpiece,principal piece,tail,and total sperm lengths were 13.39,52.35,65.74,and 73.05 μm,respectively.The mitochondria in the midpiece consisted of approximately 48 gyres and had a 9＋9＋2 axonemal pattern.After freezing and thawing,sperm showed partly intact acrosomes and plasma membrane defects,and sperm breakages,twists,and swellings were found.The tree shrew had similar ultrastructure with other mammalians except for the mitochondria number and the sperm size.Ultrastructural alteration is still the main cause resulting in poor sperm after cryopreservation.