Skutelsky E, Maymon B B, Maymon R, Shalgi R
Department of Pathology, Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel.
Histochemistry. 1992 Dec;98(5):299-304. doi: 10.1007/BF00270013.
Fertilization is a process that involves the recognition and adhesion of negatively charged spermatozoa to the oocyte investments. It is not known, however, if charge properties of the interacting gametes play a role in fertilization. The present study evaluates the content and distribution of anionic constituents in the oocyte-cumulus complex of rats. Polycationic colloidal gold (PCG), ruthenium red (RR) and wheat germ agglutinin (WGA) were used as cytochemical markers of anionic sites at the light (LM) and electron microscopical (EM) levels. Isolated oocyte-cumulus complexes were fixed with glutaraldehyde (GA) and OsO4 containing RR, or with GA without RR, and embedded in araldite or LR-gold. For LM, deresined, semi-thin, araldite-embedded sections were labelled with PCG intensified by silver, or with biotinylated lectins visualized by avidin-peroxidase. For EM, thin LR-gold sections were labelled with PCG, whereas RR labelling was examined in araldite sections. The zona pellucida (ZP) failed to bind any of the polycationic markers used, but intensely bound neutralized WGA. In contrast, cumulus cell membranes bound PCG but not RR, whereas the oolemma bound RR but not PCG. The results indicate that the ZP is practically devoid of negatively charged constituents, and tends to repel positively charged ligands possibly due to the presence of cationic determinants. The binding of PCG to cumulus cells probably reflects a high content of membrane-bound heparan sulphate, whereas the binding of RR to the oolema indicates the presence of membrane sialoglycoconjugates.(ABSTRACT TRUNCATED AT 250 WORDS)
受精是一个涉及带负电荷的精子与卵母细胞外层识别和黏附的过程。然而，相互作用的配子的电荷特性是否在受精中起作用尚不清楚。本研究评估了大鼠卵母细胞-卵丘复合体中阴离子成分的含量和分布。聚阳离子胶体金（PCG）、钌红（RR）和小麦胚凝集素（WGA）被用作光镜（LM）和电镜（EM）水平下阴离子位点的细胞化学标记物。分离的卵母细胞-卵丘复合体用含RR的戊二醛（GA）和四氧化锇固定，或用不含RR的GA固定，然后包埋在环氧树脂或低粘度LR-金中。对于光镜观察，脱树脂的半薄环氧树脂包埋切片用经银增强的PCG标记，或用抗生物素蛋白-过氧化物酶可视化的生物素化凝集素标记。对于电镜观察，薄的LR-金切片用PCG标记，而RR标记则在环氧树脂切片中检查。透明带（ZP）未能结合所使用的任何一种聚阳离子标记物，但能强烈结合经中和的WGA。相反，卵丘细胞膜结合PCG但不结合RR，而卵细胞膜结合RR但不结合PCG。结果表明，透明带实际上缺乏带负电荷的成分，并且可能由于阳离子决定簇的存在而倾向于排斥带正电荷的配体。PCG与卵丘细胞的结合可能反映了膜结合硫酸乙酰肝素的高含量，而RR与卵细胞膜的结合表明存在膜唾液酸糖缀合物。（摘要截断于250字）
