不同季节牛体外受精胚的发育能力和细胞遗传学分析

本实验对不同季节的荷斯坦奶牛体外受精 48h后的卵裂率、受精卵的发育能力及细胞遗传学进行了分析研究。结果表明 ,在夏季 ( 7- 9月 ) ,牛体外受精后的卵裂率及囊胚的发生率均低于其它季节。将这些囊胚制作染色体标本 ,通过细胞遗传学分析 ,夏季体外受精后发育的囊胚的卵裂细胞数明显少于其它月份的卵裂细胞数(P <0 .0 5)。

Effects of MEK inhibitor U0126 on meiotic progression in mouse oocytes: microtuble organization, asymmetric division and metaphase Ⅱ arrest

In this study we used U0126, a potent and specific inhibitor of MEK, to study the roles of MEK/ERK/p90rsk signaling pathway in the meiotic cell cycle of mouse oocytes. The phosphorylation of MAP kinase and p90rsk in the oocytes treated with 1.5 μMU0126 was the same as that in oocytes cultured in drug-free medium. With 1.5 μM U0126 treatment, the spindles appeared normal as they formed in oocytes, but failed to maintain its structure.Instead, the spindle lost one pole or elongated extraordinarily. After further culture, some oocytes extruded gigantic polar bodies (＞30 μm) that later divided into two small ones. Some oocytes underwent symmetric division and produced two equal-size daughter cells in which normal spindles formed. In oocytes with different division patterns,MAP kinase was normally phosphorylated. When the concentration of U0126 was increased to 15 mM, the phosphorylation of both MAPK and p90rsk were inhibited, while symmetric division was decreased. When incubating in medium containing 15 μM U0126 for 14 h, oocytes were activated, but part of them failed to emit polar bodies. MII oocytes were also activated by 15 μM U0126, at the same time the dephosphorylation of MAP kinase and p90rsk was observed. Our results indicate that 1) MEK plays important but not indispensable roles in microtubule organization;2) MEK keeps normal meiotic spindle morphology, targets peripheral spindle positioning and regulates asymmetric division by activating some unknown substrates other than MAP kinase/p90rsk; and 3) activation of MEK/ERK/p90rsk cascade maintains MII arrest in mouse oocytes.

Pins homolog LGN regulates meiotic spindle organization in mouse oocytes

Mouse oocytes undergo polarization during meiotic maturation, and this polarization is essential for asymmetric cell divisions that maximize retention of maternal components required for early development. Without conventional centrosomes, the meiotic spindle has less focused poles and is barrel-shaped. The migration of meiotic spindles to the cortex is accompanied by a local reorganization and polarization of the cortex. LGN is a conserved protein involved in cell polarity and regulation of spindle organization. In the present study, we characterized the localization dynamics of LGN during mouse oocyte maturation and analyzed the effects of LGN upregulation and downregulation on meiotic spindle organization. At the germinal vesicle stage, LGN is distributed both cytoplasmically and at the cortex. During maturation, LGN localizes to the meiotic spindle apparatus and cortical LGN becomes less concentrated at the actin cap region. Excessive LGN induces meiotic spindle organization defects by elongating the spindle and enhancing pole focusing, whereas depletion of LGN by RNA interference results in meiotic spindle deformation and chromosome misalignment. Furthermore, the N-terminus of LGN has the ability of full-length LGN to regulate spindle organization, whereas the C-terminus of LGN controls cortical localization and polarization. Our results reveal that LGN is cortically polarized in mouse oocytes and is critical for meiotic spindle organization.

Role of animal pole protuberance and microtubules during meiosis in sea cucumber Apostichopus japonicus oocytes

Fully grown oocytes of Apostichopus japonicus have a cytoplasmic protuberance where the oocyte attaches to the follicle. The protuberance and the oolamina located on the opposite side of the oocyte indicate the animal-vegetal axis. Two pre-meiotic centrosomes are anchored to the protuberance by microtubules between centrosomes and protuberance. After meiosis reinitiation induced by DTT solution, the germinal vesicle (GV) migrates towards the protuberance. The GV breaks down after it migrates to the oocyte membrane on the protuberance side. The protuberance then contracts back into the oocyte and the first polar body extrudes from the site of the former protuberance. The second polar body forms beneath the first. Thus the oocyte protuberance indicates the presumptive animal pole well before maturation of the oocyte.

Experimental study of gemcitabine combination with radiation in vitro on a highly metastatic human ovarian cancer cell line HO-8910PM

Objective： The aim of the study was to investigate the mechanism of gemcitabine （GEM） combination with radiation on the high metastasis human ovarian cancer cell line （HO-8910PM）. Methods： Human ovarian cancer cell line HO- 8910PM was treated with different concentrations of gemcitabine for 24 h, then the cells were counted. In the study of GEM combination with radiation, an efficiency of colony formation was observed; the cell cycle and apoptosis were analyzed by flow cytometry; the experiment of depend on the time and its radio sensitivity were observed by using mitotic index with the cells for each 24, 48, 72 and 96 h after experiment. Results： It suggested that the GEM had an inhibition effect on the human ovarian cancer cell line. The alive cell numbers were decreased by following a height of GEM concentration. When GEM in combina- tion with a radiation, the suppression was significantly increased than that of single GEM therapy. The efficiency of colony formation was significantly lower, under this condition the cell could be arrested at G0-G1 phase and could be decreased to enter into the S phase; the apoptosis percentage could be significantly increased; especially, under the 4 Gy and 6 Gy doses the cell apoptosis was more obvious. GEM combination with radiation had depended on the time to the cells; mitotic index of the calls in combination group was observed significantly lower than that of single GEM therapy or single radiation, and this showed that it had an effect of radiosensitivity. Conclusion： The GEM has a significant growth inhibition on the human ovarian cancer cells, GEM combination with radiation could induce HO-8910PM cell occurred arrested and apoptosis. It has depended on the time and has a radiosensitivity effect. The result shows that it is a better method to treat the human ovarian cancer by using radiotherapy combined with gemcitabine.

胚胎碎片对囊胚形成结局的影响

目的 探讨胚胎碎片率对囊胚培养结局的影响.方法 回顾性分析行D3优质胚胎移植、剩余胚胎行囊胚培养的7935个胚胎的相关信息,根据D3胚胎碎片率分为3组：碎片率≤5 %为A组,碎片率6 % ~20 %为B组,碎片率〉20 %为C组;再根据卵裂期胚胎数将胚胎分为〉8细胞、8细胞、7细胞、6细胞、5细胞、4细胞组,比较各亚组不同碎片率胚胎的囊胚形成结局.结果 A组、B组囊胚形成率、优质囊胚率均优于C组,且B组优于A组;在各个卵裂球细胞亚组中,A组与B组囊胚形成结局没有显著差异,除〉8细胞组胚胎外,其余各亚组中,A、B组的囊胚形成率及优质囊胚率均显著高于C组;当碎片率〈5 %时,〉8细胞胚胎与8细胞胚胎的囊胚形成率及优质囊胚率均显著高于〈8细胞数胚胎;当碎片率为6 % ~20 %时,〉8细胞胚胎囊胚形成率显著高于〈8细胞胚胎,优质囊胚率显著高于〈6细胞胚胎,8细胞胚胎囊胚形成率及优质囊胚率均显著高于〈7细胞胚胎;当碎片率〉20 %时,〉8细胞胚胎囊胚形成率显著高于〈6细胞胚胎,优质囊胚率显著高于〈7细胞胚胎,8细胞胚胎囊胚形成率及优质囊胚率均显著高于〈7细胞胚胎.Logistic回归结果表明,碎片率、卵裂球细胞数均对囊胚培养结局有显著影响.结论 碎片率、卵裂球细胞数与囊胚培养的结局密切相关.在影响囊胚形成的作用上,当碎片率〈20 %时,卵裂球细胞数效应相对较大,而当碎片率〉20 %时,碎片的影响效应可能更大.