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1.
This study was conducted to examine whether cat spermatozoa stored in ethanol for 1 month was capable of developing into pronuclei and of supporting normal embryonic development. In vitro matured oocytes were injected with frozen-thawed spermatozoa and ethanol-stored spermatozoa. The status of oocytes and sperm nuclei was examined at 4 and 18 h after injection of spermatozoa, and the presumptive zygotes were cultured for 7 days to assess the development of oocytes injected with each storage sperm. The percentage of enlarged sperm head at 4 h after injection was higher in ethanol-stored spermatozoa than in frozen-thawed spermatozoa, but there was no significant difference in the development of oocytes and sperm nuclei at 18 h after injection between the two groups. The development of oocytes to the blastocyst stage after injection of spermatozoa was observed only in oocytes with frozen-thawed spermatozoa. Of oocytes injected with ethanol-stored spermatozoa, two (2.8%) oocytes developed to the 16-cell stage. These results indicate that cat spermatozoa stored in ethanol can decondense and form male pronuclei after intracytoplasmic injection. However, the oocytes injected with ethanol-stored spermatozoa did not have the ability to develop to the blastocyst stage.  相似文献   
2.
The chemical toxicity of cryoprotectants to porcine embryos was examined by the evaluation of survival and DNA damage after exposure to cryoprotectants. Porcine blastocysts were exposed to 10% of ethylene glycol (EG), 1,2-propanediol (PD) or glycerol (GLY) for 1 h at room temperature (23-25 degrees C) and then cultured in vitro for 24 h. The survival rates of blastocysts exposed to PD and GLY were significantly lower than those of control blastocysts in which the embryos were exposed to carrier solution without cryoprotectants. Significantly more DNA-fragmented nuclei occurred in the cryoprotectant-exposed blastocysts, compared with the control blastocysts. Moreover, the indices of DNA-fragmented nuclei in the blastocysts without blastocoele re-formation after culture were significantly higher than those with blastocoele re-formation, irrespective of the exposure treatment. These results indicate that the exposure of porcine blastocysts to cryoprotectant decreases the survival rates and increases the DNA-fragmented nuclei in embryos.  相似文献   
3.
We conducted two experiments to investigate the effects of storage temperature and period for cat ovaries on the meiotic and developmental competence of oocytes collected from the ovaries. In Experiment 1, ovaries were stored in physiological saline for 24 h at 4 C, 23-25 C, or 38 C (cold, room, and incubator temperature groups, respectively), and then oocytes were collected from the ovaries in each group. Morphologically intact oocytes were then selected and cultured in maturation medium for 24 h. Significantly more oocytes reached metaphase II (MII) in the cold temperature group (53.4%) than in the room and incubator temperature groups (20.0 and 2.4%, respectively). In Experiment 2, ovaries were stored in physiological saline at room temperature for 0, 6, 12 or 18 h, and then they were stored at 4 C (cold storage) until reaching a total storage period of 24 h. After storage of the ovaries, morphologically intact oocytes were matured, fertilized with frozen-thawed spermatozoa, and cultured in vitro. The rates of morphologically intact oocytes obtained from the ovaries stored at room temperature for 0, 6, 12 or 18 h were 35.3, 30.0, 26.4 and 14.7%, respectively, and the rates of intact oocytes that reached MII were 63.2, 36.4, 26.5 and 11.9%, respectively. The results suggested that the numbers of morphologically intact oocytes and intact oocytes that reached MII after in vitro maturation decrease gradually as the period of storage at room temperature before cold storage increases. Only oocytes from ovaries stored for 6 h developed to the blastocyst stage after in vitro maturation and fertilization when ovaries were stored at room temperature before cold storage. These results indicate that 24 h storage of ovaries at high temperatures (>23 C) decreases the meiotic competence of oocytes. The quality and developmental competence of oocytes are influenced by the length of storage at room temperature before cold storage.  相似文献   
4.
The ultimate goal of this study was to establish an in vitro system to produce sperms. To pursue this goal, immature porcine testicular cells were cultured in stereostructural form and cultured testicular cord was investigated morphologically. At 4 weeks of age, the seminiferous tubules of the porcine testes consisted of undifferentiated germ cells (gonocytes and undifferentiated spermatogonia) and immature Sertoli cells. The interstitial tissue was largely occupied by Leydig cells. The testes were enzymatically digested, and the dispersed cells were encapsulated with alginate either immediately or after freeze-thawing. The resulting testicular cell cords were cultured for up to 10 weeks. After 2 weeks of culture, Sertoli cells, which were identified by their inhibin-positive reaction in immunohistochemistry, and Leydig cells, which were identified by their morphological characteristics, were observed in the cords. Neither undifferentiated nor differentiated types of germ cells were detected. The number of cells in the cords progressively decreased during the culture period. In order to discover the fate of the Sertoli cells, the level of inhibin in the spent media was determined. Inhibin in the media was at a detectable level after 2 days of culture. The levels increased and peaked at 2 weeks. When frozen-thawed testicular cells were applied to the culture, the peak level was maintained for over 8 weeks, in contrast to the gradual decrease of inhibin level when fresh cells were cultured. These results indicate that the culture conditions can sustain the survival of Sertoli cells. Further improvement is required for proliferation and differentiation of germ cells.  相似文献   
5.
This study was conducted to determine the adequate medium for a serum‐free culture system of domestic cat embryos produced by in vitro maturation (IVM) and fertilization (IVF). Cumulusoocyte complexes recovered from cat ovaries were matured in vitro for 24 h, and then inseminated in vitro for 12 h. After insemination, the oocytes were cultured in five media [Ham's F10, Waymouth 752/1 (Waymouth), TCM199, modified Earle's balanced salt solution (MK‐1) and CR1aa], each of which contained 0.4% bovine serum albumin. There were no significant differences among the rates of fertilization of oocytes cultured in five media following IVF. The rate of oocytes/embryos developed to at least the morula stage was significantly lower (p < 0.05) in Waymouth than in MK‐1, TCM199 and CR1aa. Moreover, none of the embryos cultured in Ham's F10 and Waymouth developed to the blastocyst stage. There were no differences among the rates of development to the blastocyst stage of oocytes/embryos cultured in MK‐1, TCM199 and CR1aa. These results indicate that the type of serum‐free medium has a major impact on in vitro development of domestic cat embryos derived from IVM/IVF, and MK‐1, TCM199 and CR1aa media are suitable for in vitro culture of cat embryos in a serum‐free culture system.  相似文献   
6.
The effect of glucose supplementation at different times in in vitro culture on the developmental competence of in vitro produced (IVP) porcine embryos was examined. In Experiment 1, when IVP embryos were cultured in modified NCSU-37 supplemented with pyruvate and lactate (IVC-pyr/lac) for 0 h, 24 h, 48 h, 72 h, 96 h, or 118 h and subsequently in modified NCSU-37 supplemented with glucose (IVC-glu) until Day 6 (Day 0=day of in vitro fertilization), the rates of blastocyst formation were significantly higher in embryos cultured in IVC-pyr/lac for 24 or 48 h (24.4% and 23.0%, respectively) than in embryos cultured in IVC-pyr/lac for the whole culture period (14.5%). However, there were no significant differences between embryos obtained after the energy source replacement and embryos cultured in IVC-glu for the whole culture period on the rates (15.2%-24.4%, and 16.8% respectively). Replacement of pyruvate/lactate with glucose at 58 h of culture in Experiment 2 significantly enhanced the rate (31.3%) compared to those after replacement at 48 h, 53 h and 63 h of culture (20.6%, 20.8%, and 21.1%, respectively). In conclusion, replacement of pyruvate/lactate with glucose as the energy substrate was optimal at 58 h of culture for the development of porcine embryos to the blastocyst stage.  相似文献   
7.
The present study was conducted to investigate the effects of storage time and temperature of porcine ovaries on the quality and nuclear maturation in vitro of oocytes obtained from stored ovaries and their subsequent development after in vitro fertilization. The ovaries were stored in physiological saline for 0, 3, 6, 9 and 12 h at various temperatures (4, 15, 25 and 35 C). The pH of follicular fluid obtained from the ovaries, DNA fragmentation of the oocyte nucleus and meiotic competence of oocytes were examined. Some oocytes from ovaries stored at 15, 25 and 35 C for 6 h were fertilized in vitro, and then cultured for 7 days to examine the ability of embryos to develop to the blastocyst stage. When the ovaries were stored at 35 C, the pH of follicular fluid decreased and the proportions of oocytes with DNA fragmented nuclei increased as the storage time was prolonged, and the storage of ovaries for 6, 9 and 12 h resulted in lower maturation rates of oocytes. When the ovaries were stored at 4, 15, 25 and 35 C for 6 h, the storage at higher temperatures (> or =15 C) decreased the pH of follicular fluid and induced nucleic DNA fragmentation in higher proportions of oocytes. None of the oocytes from ovaries stored at 4 C reached metaphase II. The storage of ovaries at 15 C reduced the rates of in vitro fertilized oocytes and subsequent embryo development, but there were no significant differences in the rates of fertilization and blastocyst formation between oocytes from ovaries stored at 25 C and 35 C. Our findings indicate that the storage of ovaries at 25-35 C for 6 h is effective for maintaining the developmental competence of porcine oocytes even though the development rates were lower than those of ovaries stored at 35 C for 3 h.  相似文献   
8.
The crude testicular cells (CTCs) contain many cell types, such as Sertoli cells, leydig cells, spermatogonial stem cells (SSCs), spermatocytes, and other somatic testicular cells, that secrete various growth factors needed in spermatogenesis. The objective of this study was to characterize development of 5‐day‐old mice testicular cells cultured. Crude testicular cells prepared from the testes of 5‐day‐old male mice were cultured in Dulbecco's Modified Eagle Medium and incubated at 37°C in a 5% CO2 atmosphere for 6 days. The results demonstrated that the testicular cells developed rapidly with a population doubling time (PDT) of 0.63 days and more than 90% of cells were viable after being cultured for 3 days. The number of Sertoli‐like cells increased significantly over days 1, 3, and 6 to 22.1%, 34.6%, and 50.1%, respectively. A significant increase was also observed in fibroblast‐like cells (15.5% on day 1 to 28.8% on day 3 and to 26.6% on day 6). In contrast, the number of spermatogonia‐like cells decreased significantly (54.3%, 30.4%, and 18.7%, on days 1, 3, and 6, respectively). These data indicated that the developmental pattern of the testicular cell in this study might be affected by the niche provided by the cultured testicular cells.  相似文献   
9.
This study was conducted to improve parthenogenetic development in vitro of feline oocytes following a combined activation treatment of electrical stimulation and cycloheximide. In vitro matured (IVM) oocytes were stimulated electrically by a DC electrical pulse of 2 kV/cm for 50 micros. The stimulated oocytes were then incubated in MK-1 medium with or without cycloheximide and subsequently cultured in vitro for 6 days. No significant differences were observed between the two groups with respect to the proportions of cleavage, development to the morula stage, and the cell number of blastocysts. However, exposure of electrically stimulated oocytes to cycloheximide significantly increased the rate of development of the stimulated oocytes into the blastocyst stage compared with oocytes stimulated by electrical stimulation alone (31.0% vs 6.7%). The results from the present study suggested that a single electrical stimulation was insufficient to activate the IVM cat oocytes at 24 h of maturation and that exposure to cycloheximide following electrical stimulation improved the efficacy of the parthenogenetic development of domestic cat oocytes.  相似文献   
10.
This study was conducted to examine the effects of the reproductive cycle of donor cat on the quality of oocytes at recovery and developmental competence of oocytes after in vitro fertilization (IVF) and somatic cell nuclear transfer (NT). Based on the presence or absence of follicles and corpora lutea, the ovarian pairs collected were classified into inactive, follicular or luteal stages. After collection of oocytes, the oocytes were classified into four grades according to the morphological condition of oocyte cytoplasm and cumulus cells. A total of 16 558 oocytes were obtained from 198 ovarian pairs. The total mean numbers of oocytes and the mean numbers of oocytes with high quality (grade I) were significantly higher in ovarian pairs at the inactive stage (111.1 and 19.0 oocytes, respectively) than in ovarian pairs at the follicular stage (67.1 and 11.4 oocytes, respectively). A significant difference in the proportions of oocytes with grade I out of the total examined oocytes was observed between the follicular and luteal stages of ovaries (14.9% vs 20.2%, p < 0.05). The proportions of IVF embryos cleaved and developed to blastocysts significantly decreased with decreased quality of oocytes at recovery, irrespective of the reproductive status of ovaries. Moreover, there were no significant differences in the proportions of cleavage and development to the blastocyst stage of IVF and NT embryos among three oestrous stages of ovaries. These results indicate that the reproductive cycle stage of donor cat ovaries has no apparent effects on the in vitro development of oocytes after IVF and NT, but the quality of oocytes at recovery influences the development of IVF embryos.  相似文献   
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