人类精子的超微结构——冷冻复型法电子显微镜观察

FINE STRUCTURE OBSERVATIONS OF HUMAN SPERMATO-ZOA BY MEANS OF FREEZE-ETCH REPLICA TECHNIQUES

应用冷冻复型电子显微镜技术,研究了正常人类精子的超微结构,通过观察分析,作者发现如下现象并提出了相应的推论。一、按照结构特点,精子头可分为前、中、后三头区,形态结构的这种区域性,反映了生理功能的区域性。二、质膜内外片的膜内颗粒,具有不同的区域性;在前头区内片膜内颗粒丰富;中头区内片从断裂面看膜面平滑、颗粒少,从胞质面看有成群散在的表在性膜蛋白粒;后头区质膜内外片贴附紧密,并与核膜相贴,结构坚韧,可提供精子尾保持牢固附着的部位;精子尾质膜PF面颗粒丰富,但未见任何特异的排列方式。三、顶体极大,分前后两部,遮盖核表面十分之八九;前顶体位于前头区范围,膜内颗粒丰富,外形肥厚,充满内容物,内膜层有孔状结构;后顶体则位于中头区范围,膜内颗粒少,内外膜相贴,外形干瘪。四、细胞核极性明显,在前头区核孔无规律,中头区核孔不明显,后头区核孔大而密,排列成规律的六角式;作者推论:核的前头区可能发出控制顶体囊蛋白水解酶活性及细胞识别的化学信息,经核孔传出,后头区大概也发出化学信息,经核孔输向尾侧,以协调统筹轴丝微丝运动的绝对同步及线粒体的能量释放。

Ultrastructural observations on human spermatozoa preserved by 3%glutaraldehyde and prepared by freeze-etch replica techniques were carried out.The results were as follows:1.According to the structural features,the head of human sperm may be divided into three distinct different regions,namely,fore-head,mid-head and hind-head.This regional distinction may represent the functional differences.2.Regional difference of the intramembranous particles of the inner-and outer-leaflets of the plasma membrane was also revealed.The intramembranous particle is very rich in the fore-head region of inner-leaflet.However,the mid-bead region is very smooth and there are only a few particles attached on its fractured face,but groups of extrinsic membrane particles can be seen on its inner plasma-face.As for the hind-head region the inner-and outer-leaflets of the unit membrane contact closely with each other and attach tightly to the nuclear membrane.It is suggested that this structure is prerequisite for attaching the tail to the head firmly.The PF-face of sperm tail pla-sma membrane is rich in particles but without special pattern in arrangement.3.The acrosome is extremely large,almost 8/10~9/10 of the nuclear surface is covered by it,its posterior margin sometimes is described as“posterior ring”.Two distinc-tive parts may be seen on the acrosome:The fore-acrosome,which corresponds to the fore-head region,is rich in membrane particles.It looks plump in appearance and is filled up with content.There is also pore-like structure at the internal membrane of the acrosomal cap.The hind-acrosome part,corresponds to the mid-head region.There are less particles than the fore-acrosome part.Its external and internal membranes contact with each other and it looks lean in features.4.The polarity of the nucleus is very obvious.On the anterior part of the nucleus the nuclear pores are distributed irreglarly,and in the middle part there is no pore,but in the posterior part the nuclear pores are large and arranged closely as regular hexagonal arrays.A hypothesis is proposed that the anterior part of the nucleus may regulate the activity of acrosomal hydrolase by chemical message which is presumably produced by the chromosome and transfered from the nuclear pore through the pore of the acrosomal membrane into the cavity of the acrosome.The posterior part of the nucleus is thought to be the place where the chemical message,which may be the pro-duct of a particular gene,is transfered through the nuclear pores to the tail,and it can adiust the absolutely synchronous movement of the axial microfilarnents and modulate the oxidation phosphorylation and energy-release of the mitochondria.