【摘要】 对兔核移植胚胎起始发育的超微结构变化进行电镜观察，并与供体桑椹胚细胞、受体卵母细胞 及同期正常受精胚胎的超微结构进行比较．“原核”期兔核移植胚胎的超微结构明显不同于供体桑 椹胚细胞及受体卵母细胞的超微结构；而与同期正常受精胚胎相似．但有些核移植胚胎中皮质反 应，及核仁和线粒体中出现电子致密的网眼结构，与正常受精卵存在差别．分裂至２－细胞期时，与 正常２－细胞胚超微结构更相似．结果提示：兔胚胎细胞核移植后，供体核和受体胞质间发生了相互 作用．移植的核被重新定型，且有些延迟。有些胚胎出现不正常分裂或异常结构，如染色质碎片。 这些会影响核移植胚胎以后的发育能力。更多还原

【Abstract】 The ultrastructural changes during initial development of rabbit nuclear transplant (NT) embryos were observed and compared with the ultrastructures of donor embryonic cells, recipent oocytes, and fertilized embryos at the similar stages. Changes in fine structures of the following selected cellular components were examined in serially ultrathin sectioned embryos: (1) nuclear envelope and nucleon, (2) conical granules, mitochondria, ribosomes and polysomes, endoplasmic reticulum, and related membrane system including membrane-granule complexes and annulate lamellae, (3) microvilli and intercellar junction, and (4) other structures. The results showed that the ultrastrucures of the rabbit NT embryos at the pronuclear stage were evidently different from the structures of donor morulae cells and recipient oocytes. Except for a few differences such as the conical reactron and the appearance of election densed meshwork structure (EDMS) in the nucleolus and mitochondia in some rabbit NT embryonic cells as compared with the zygotes, no any other abnormalities were found. The ultrastructures of NT embryos were more similar to the fertilized embryos when they cleaved to the 2-cell stage. The observations suggest that interactions between transferred nucleus and recipient cytoplasm occurred following nuclear transplantation in rabbit embryos. Extensive remodeling can be induced in the nuclei that are transferred to oocyte cytoplasm. But some minor differences or abnormal cleavage (2 nuclei) and the appearance of dispersed chromatin fragments in some rabbit NT embryos, compared with fertilized embryos, may affect subsequent developmental competence.更多还原