【摘要】 <正> 绪言哺乳类动物雌性生殖细胞的来源和它的演变情形,曾经有许多学者从各方面来进行研究,因为这个问题是一个需要解决的、而且是富有兴趣的生物学的基本问题。在这方面学者们的实验结果与见解都很不一致(Everett,1944),近来关于这个问题还有许多新的研究工作陆续登表,可综合成为三类:更多还原

【Abstract】 A great number of contributions have been presented within recent years dealing with the problems of the origin of the definitive germ cells in mammalian ovary.Many investigators believe that most of those sex cells which are present at the time of parturition degenerate,and the definitive ova are derived from cells of the germinal epithelium of the ovary.Others maintain that those germ cells which are found previous to the time of birth,are the progenitors of the definitive ova in adult.Thus conflicting opinions are held by different workers concerning whether the germinal epithelium is active in oogenesis during the prepubertal and postpubertal life.Further investigations are needed in order to shed more light on these problems.This paper presents some experimental observations on the relation of germinal epithelium to the number of oocytes in the ovaries of mice subsequent the chemical destrution of the germinal epithelium.47 female mice were used and were divided into two groups. Ⅰ.Control group:Ten mice served as controls.The number of oocytes in 16 ovaries of these mice was counted according to the nucleoli which were taken as markers.The average number of oocytes in the ovaries of this group was 1429.88. Ⅱ.Experimental group:The left ovaries of 37 immature and 10 mature mice were exposed through an incision in the dorsal body wall on the surface,the ovarian bursa was open,then a jell of 40% salicylic acid dissolved in 12% colloidin was spread evenly over the entire ovarian surface.The treatment of this corrosive chemical substance destroyed the germinal epithelium,while the inner portion of the cortex remained in normal condition (Fig.1).Right ovaries of these animals were removed in the same operation. Both untreated and treated ovaries together with other organs were fixed in Bouin’s fluid,and the ovaries were cut in serial sections,6—8 micra in thick- ness,and stained with hematoxylin and eosin. Histological examinations of the celloidin-salicylic acid treated ovaries revealed that the results were varied with the degree of the destruction of germinal epithelium. A).The immature mice were killed in 55—328 days following the operation and three conditions were observed in these ovaries: (1) No germinal epithelium-covered surface was noted in 14 ovaries,and in the place the ovarian tissue was firmly encapsulated by a thick connective tissues mass.In the ovarian stroma neither oocytes nor corpora lutea was present (Fig. 2).The luteinized stroma cells contained vacuoles of varying sizes and most of the stroma cells were arranged in glandular structure (Fig.3).The stroma cells were physiologically inactive as indicated by the atrophic condition of the uterine endometrium (Fig.4). (2) 11 ovaries retained a small amount of inactive squamous germinal epithelium on the surface,and the rest part of the ovary was covered by the connective tissue.Some follicles,antrum-bearing follicles,blood follicles and old corpora lutea were present in these ovaries,but all these structures showed degenerative changes.Besides,no recent corpora lutea were encountered and the stroma cells were also lutinized and vacuolated (Fig.7),some of which showed glandular arrangement. (3) A part of active germinal epithelium remained on the surface of 12 ovaries.The germinal epithelium separated into two layers in several cases (Fig. 8).Just beneath the germinal epithelium some degenerative follicles were present.The stroma cells of these oyaries did not arrange in glandular form. B).Ten ovaries from 20 mature mice were treated with the celloidin-salicylic acid,and were examined in 58—155 days subsequent to the operation.The ger- minal epithelium was present in some areas on the surface of the ovaries.Since the germinal epithelium of the postpubertal ovary was Usually invaginated (Fig.9), complete removal of the germinal epithelium was difficult to achieve.These ovaries contained ova of all stages of follicular development,and neither corpora lutea nor glandular arrangements was present.However the number of the follicles was much fewer than in the normal ovary (Fig.10).The experimental results showed that the number of the oocytes in the overies of mice was dependent upon the amount of germinal epithelium present.The presence of germinal epithe- lium was essential for oogenesis and the process of oogenesis was continued from, the prepubertal to postpubertal stage.更多还原