猪卵子体外受精方法研究

本试验分析研究了：（1）猪卵子体外成熟所需要的培养时间；（2）促性腺激素和猪卵泡液对猪卵子体外成熟的作用；（3）不同体外受精次数对猪卵子体受精率的影响；（4）不同精子获能辅助剂对猪精子体外获能的作用；（5）不同种类猪精液的体外受精能力。研究结果表明，猪卵子体外成熟所需培养时间是32－36小时，在体外成熟培养液中加入0.25IU/ml PMSG（或FSH）和10％猪卵泡液可以促进猪卵子体外成熟，在精子体外获能培养液中加入0.05mg/ml肝素，在体外受精培养液中加入2mg/ml咖啡因可以促进猪精子体外获能并可提高体外受精率，体外成熟后的猪卵子进行2次受精可以获得较高的体外受精率，本试验用新鲜射出精子，冷冻射出精子，新附睾精子，冷冻附睾精子对体外成熟猪卵子进行体外受精，受精后卵裂率（2－4细胞期）分别是24.26％、23.40%,22.65%和24.24%。     

猪卵子体外成熟方法研究

本文根据猪卵子带卵丘细胞不同,将卵子分为 A—D4级。实验表明,使用不同成熟培养时间和多次受精法,可以使处于不同发情期的卵子获得较高的体外受精率。B、C、D 级卵子(完整、部分完整或无卵丘)培养32—36小时后受精,体外受精率(2细胞率)25.60％,17.61％和15.78％。A 级卵(放射状卵丘)培养4—15小时后受精,体外受精率62.50～66.67％。在m—KRB 和 m—TCM 199培养液中添加卵泡液和 FSH 或 PMSG 可以促进卵子体外成熟,卵丘扩散成放射状。特别是用即将排卵的猪的大卵泡液和发情黄牛卵泡液,其效果更优。使用这两种培养液的平均受精率分别是19.78％和29.58％,最高30.23％和43.48％。将猪卵子移入小鼠和大鼠子宫角以及兔输卵管中进行卵子成熟培养获得成功,体外受精率分别是10.42％、28.45％和36.36％。     

透明质酸对猪精子活率,获能,顶体反应及体外受精穿透率的影响

采用具有高繁殖力的种公猪的新鲜精液及冷冻精液，加入不同获能剂咖啡因及透明质酸，在３９．５℃、５％ＣＯ２培养箱中孵化培养。结果表明，透明质酸能够在体外条件下保持精子的活率，并维持在稳定的水平，鲜精为４２．６％～４７．８％，冻精为２０．４％～２５．６％。荧光剂Ｈｏｅｃｈｓｔ染色表明，透明质酸能够显著增加培养３６０ｍｉｎ后的活精子率。在无蛋白来源的ｍＢＯ培养液中，培养０～６０ｍｉｎ，精子发生自发的获能和顶体反应，而受获能剂影响，精子发生获能的时间带在各处理组之间显著不同：咖啡因处理组的获能时间带是６０～３６０ｍｉｎ，透明质酸处理组则是６０～１８０ｍｉｎ。体外受精试验表明，去除卵母细胞周围卵丘细胞时，透明质酸和咖啡因对精子穿透率的影响没有区别；而在卵丘细胞存在的前提下，咖啡因处理组的穿透率显著高于透明质酸处理组。     

肝素和钙离子载体诱导波尔山羊精子体外获能和体外受精

运用肝素、钙离子载体（IA）协同咖啡因诱导波尔山羊精子体外获能，利用去透明带金黄地鼠卵穿透试验检测了精子的获能效果。结果发现：精卵孵育4h和6h时的穿透率均高于2h时的穿透率；肝素和钙离子载体对精子获能有明显的促进作用，与未添加组相比差异极显著（P〈0．01）；20mg／L和50mg／L的肝素剂量组，去透明带金黄地鼠卵穿透率为64．7％、68．4％；钙离子载体的添加剂量在0．3μmol／L时，穿透率达到68．2％；咖啡因与肝素、钙离子载体具有明显的协同作用。将获能的精子与山羊卵母细胞进行体外受精孵育17h，也获得了60％以上的受精率。     

小鼠精子透明质酸酶SPAM1在受精过程中的功能研究

旨在研究小鼠精子透明质酸酶SPAM1(Sperm adhesion molecule 1)对受精过程中精子/卵丘互作的影响,并初步探讨其可能的作用机制。本研究抽提小鼠尾尖基因组,利用PCR法检测小鼠Spam基因型;筛选的野生型(WT)和Spam1敲除(KO)小鼠,提取附睾尾部精子蛋白进行Western blot和酶活性检测;经TYH培养液2h获能后,分别对精子的运动性、穿透和分散卵丘细胞能力及体外受精(IVF)进行统计分析。结果表明,KO小鼠精子中未检测到SPAM1蛋白,透明质酸酶活性也极显著低于WT小鼠(P0.01);而获能后精子运动性,在KO和WT小鼠之间差异不显著(P0.05);与WT相比,KO小鼠精子缺失Spam1后,极显著地影响卵丘细胞层基质中精子顶体反应的发生比率(P0.01),导致精子穿透卵丘细胞层的能力极显著降低(P0.01),仅有少数精子能够到达卵子透明带表面,大量精子极易黏附于卵丘细胞层表面或外部边缘(P0.01);此外,KO小鼠精子IVF 2h的卵丘细胞分散和受精率均呈现显著延迟(P0.05)。综上表明,小鼠精子透明质酸酶SPAM1与顶体反应相关联并影响精子/卵丘互作。揭示SPAM1在穿卵过程中除了具有降解透明质酸的作用外,还存在其他的非酶活性功能。     

高产奶牛连续活体采卵及卵母细胞体外受精

在超声波扫描仪的指导下,用双孔型采卵针以 １４．７ ｋ Ｐａ 抽吸压经阴道对 ５ 头高产奶牛分别连续实施 ７ 次活体采卵,每 ７ ｄ １ 次,共采集卵子 ２１４ 个,占可见卵泡数的 ５３．９％ ,每次头均采集卵子 ６．１ 个。卵子经过体外培养、体外受精、体外受精胚体外发育培养,于体外受精后 ４８ ｈ 、１６８ ｈ 统计的卵裂率、囊胚发育率分别为 ７５．２％ 和 ２９．７％ 。研究结果表明,在超声波扫描仪指导下对奶牛连续进行活体采卵是可行的,所得卵子应用体外成熟、体外受精、体外培养技术,可生产用于冷冻或移植的胚胎。     

家兔显微受精影响因素及显微受精胚胎超微结构

以家兔为实验动物，利用胞质内精子注射技术和透明带下精子注射技术，对卵龄、精子获能、注射针管口径、操作室温和操作方法等影响显微受精的因素以及显微受精胚胎的超微结构进行了研究。结果显示：（１）胞质内单精子注射，ｈＣＧ后１５－１７ｈ卵的存活率为６９．４％，显著（Ｐ〈０．０５）高于ｈＣＧ后１９－２１ｈ卵的存活率（４７．３％）；而受精率和卵裂率（分别为５２．９％和４１．２％）分别低于ｈＣＧ后１９－２１ｈ卵的     

海狸鼠卵母细胞体外成熟培养初探

实验用ＰＭＳＧ或ＰＭＳＧ＋ＨＣＧ处理或未经激素处理的海狸鼠８只，共获卵巢卵母细胞１３８枚。激素处理对获取卵巢卵母细胞的数量没有影响，而对体外成熟发育至卵丘扩展和半成熟阶段有促进作用。三种不同培养液（Ｗｈｉｔｅｎ＋ＦＣＳ；ＴＣＭ１９９＋ＰＭＳＧ＋ＦＣＳ；ＴＣＭ１９９＋ＨＣＧ＋ＦＣＳ）共培养１２５枚卵母细胞，培养后卵丘扩展率及半成熟率分别为５６．５％，４５．７％，４７．６％和２１．７％，１２．３％，９．５％，以Ｗｈｉｔｅｎ液较高（分别为５６．５％和２１．７％），但只有ＴＣＭ１９９＋ＰＭＳＧ＋ＦＣＳ组有２枚卵母细胞出现第一极体。结果表明海狸鼠卵母细胞与其它啮齿动物的卵母细胞一样，能够在体外培养成熟，完成第一次减数分裂，排出第一极体     

牛卵母细胞体外成熟和体外受精技术的研究进展

论述牛卵母细胞体外成熟和体外受精的最新研究进展，包括卵丘卵母细胞复合体、卵母细胞的体内、体外成熟，以及体内、体外的异常成熟和卵母细胞的体外成熟方法，无蛋白质、无血清系统的限定性培养液的研究进展，卵母细胞体外成熟状态与标志的某些理论上的突破；体外受精中精子供体的选择、精子活力和正常形态的选择、冷冻解冻精液的体外获能、精子的体外受精力，以及体外的异常受精；还论述了牛卵母细胞体外成熟和体外受精技术在家畜育种和胚胎克隆等方面的应用前景     

牛卵母细胞体外成熟和体外受精技术的研究进展

论述了牛卵母细胞体外成熟和体外受精的最新研究进展，包括卵丘母细胞复合体、卵母细胞的体内、体外成熟、以及体内、体外的异常成熟和卵母细胞的体外成熟方法，无蛋白质、无血清系统的限定性培养液的研究进展，卵母细胞全外成熟与标志的某些理论上的突破性；体外受精中精子供体的选择、精子活力和正常形态的选择冷冻解冻精液的体外获能、精了的体外受精力，以及体外的异常受精，还论述了牛卵母细胞体外成熟和体外受精技术在家畜育种     

Effect of capacitation of stallion sperm with polyvinylalcohol or bovine serum albumin on penetration of bovine zona-free or partially zona-removed equine oocytes

Experiments were conducted to study effects of macromolecules on stallion sperm capacitation and fertilization as determined by penetration of bovine zona-free and equine partially zona-removed oocytes. Stallion sperm were capacitated in TYH medium (modified Krebs-Ringer bicarbonate) supplemented with either 1 mg/mL of polyvinylalcohol (PVA) or 4 mg/mL of BSA. Capacitation was induced with 8 bromoadenosine cyclic monophosphate (8BrcAMP; 0.5 mM) alone or in combination with 0.1 microM of ionomycin. Intraspecies gametes were co-incubated in TYH/PVA or TYH/BSA for 18 to 20 h. For zona-free bovine oocytes, penetration rate (35%) with the combination of 8BrcAMP and ionomycin in PVA-containing medium was higher (P < 0.05) than any treatment in BSA-containing medium (5 to 6%). A similar study was conducted using equine oocytes with partially removed zonae. Sperm capacitated and used for in vitro fertilization (IVF) in PVA-containing medium had higher penetration rates (P < 0.01) than sperm in BSA-containing medium (54 vs. 11%). The effect of equine preovulatory follicular fluid on bovine oocyte penetration was assessed. Bovine oocytes were matured in tissue culture medium-199 with 0, 20, 50, or 100% equine preovulatory follicular fluid, and 1 IU/mL of equine chorionic gonadotropin. Stallion sperm were treated with 8BrcAMP + ionomycin in PVA- or BSA-containing media. The penetration rates of bovine zona-free oocytes by stallion sperm were again higher with PVA (47%) than BSA (18%; P < 0.01). Penetration rates of oocytes matured in 100% follicular fluid were higher (P < 0.05) than for oocytes matured with 0% follicular fluid. The effects of equine follicular fluid and PVA/BSA during sperm capacitation on standard bovine IVF were examined. Culture of bovine oocytes with equine follicular fluid did not affect oocyte maturation or penetration rates after IVF. Bovine sperm capacitated with heparin in PVA-containing medium yielded lower (P < 0.05) fertilization rates than those capacitated in BSA-containing medium when incubated with both zona-intact and zona-free bovine oocytes. In summary, PVA was superior to BSA for ionophore-induced capacitation of equine sperm for penetration of zona-free bovine oocytes or partially zona-removed equine oocytes, but not for standard bovine IVF with bovine sperm. Zona-free bovine oocytes may be useful for assaying in vitro capacitation and fertilization of stallion sperm.     

Improvement of cumulus-free oocyte maturation in vitro and its application to microinsemination with primary spermatocytes in mice

In micromanipulation experiments using immature oocytes, final ooplasmic maturation is often compromised because the oocytes are usually first freed from their nurturing cumulus cells. This study was undertaken to determine whether cumulus-free in vitro maturation (IVM) in mice could be improved by modifying IVM medium having defined components. Cumulus-free germinal vesicle (GV) stage oocytes were subjected to IVM in either alphaMEM medium, TYH medium, or a 1:1 mixture of the two (termed TaM). TYH medium produced a better maturation rate (181/196; 92.3%) than alphaMEM (184/257; 71.6%). However, alphaMEM supported better embryo development to the morula/blastocyst stage than TYH following in vitro fertilization (93.3% vs. 76.5%) or parthenogenetic activation (82.4% vs. 60.4%). Mitochondrial distribution in MII oocytes was diffuse following IVM in alphaMEM, but was aggregated with TYH. The maturation promoting factor (MPF) activity in MII oocytes was significantly higher in TYH than in alphaMEM (P<0.05). Oocytes cultured in TaM had intermediate characteristics and essentially resembled in vivo matured oocytes, with the mitochondrial distribution pattern being most typical of that condition. The highest rate of development from GV oocytes to full-term fetuses following in vitro fertilization and embryo transfer to foster mothers (23.8%) was obtained using TaM. When this IVM system was applied to MI oocytes injected with spermatocytes, offspring were first obtained without cytoplasmic replacement at MII. Thus, optimization of the culture medium can considerably improve the quality of cumulus-free oocyte IVM in mice.     

Microdroplet In Vitro Fertilization Can Reduce the Number of Spermatozoa Necessary for Fertilizing Oocytes

Successful in vitro fertilization (IVF) in mice has been achieved using spermatozoa at concentrations specifically optimized for the experimental conditions, such as species and source of spermatozoa. Although IVF in mice is mostly performed using about 80–500 µl drops, it is expected that the number of spermatozoa used for insemination can be reduced by decreasing the size of the IVF drops. The present study was undertaken to examine the extent to which the number of spermatozoa used for IVF could be reduced by using small droplets (1 µl). We devised the experimental parameters using frozen–thawed spermatozoa from C57BL/6 mice in anticipation of broader applications to other mouse facilities. We found that as few as 5 spermatozoa per droplet could fertilize oocytes (1 or 3 oocytes per droplet), although the fertilization rates were low (13–15%). Practical fertilization rates (> 40%) could be achieved with frozen-thawed C57BL/6J spermatozoa, which are sensitive to cryopreservation, when 20 sperm per droplet were used to inseminate 3 oocytes. Even with spermatozoa from a very poor quality suspension (10% motility), about 25% of oocytes were fertilized. Our calculations indicate that the number of inseminated spermatozoa per oocyte can be reduced to 1/96–1/240 by this method. In two separate embryo transfer experiments, 60% and 47%, respectively, of embryos developed to term. Our microdroplet IVF method may be particularly advantageous when only a limited number of motile spermatozoa are available because of inadequate freezing-thawing or genetic reasons.     

Effects of (−)‐Epigallocatechin Gallate on the Motility and Penetrability of Frozen–Thawed Boar Spermatozoa Incubated in the Fertilization Medium

Epigallocatechin gallate (EGCG) is the major polyphenol in green tea (Camellia sinensis) and is known for its antioxidant effects. The objective of the present study was to examine the effects of EGCG during in vitro fertilization (IVF) on the sperm quality and penetrability into oocytes. In the first experiment, the effects of concentration and incubation period of EGCG on the motility and penetrability of spermatozoa were examined. When frozen–thawed spermatozoa were incubated in IVF medium supplemented with 0 (control), 1, 50 and 100 μm EGCG for 1, 3 and 5 h, supplementation with 50 and 100 μm EGCG improved motility of the spermatozoa (p < 0.05), but not viability, as compared with the control group. When frozen–thawed spermatozoa were co‐incubated with in vitro‐matured (IVM) oocytes in IVF medium supplemented with 50 and 100 μm EGCG for 5 h, supplementation of EGCG had positive effects on sperm penetration rates. In the second experiment, the effects of supplementation of EGCG in IVF medium on penetrability of sperm from different boars and development of fertilized oocytes were evaluated. When frozen–thawed spermatozoa from six boars were co‐incubated with IVM oocytes in IVF medium supplemented with 50 μm EGCG, the effect of EGCG on sperm penetration and development of oocytes after fertilization was found to vary with individual boar. Our results indicate that motility and penetrability of boar spermatozoa are improved by co‐incubation with 50 μm EGCG, but the effects vary with individual boars.     

Generation of rats from vitrified oocytes with surrounding cumulus cells via in vitro fertilization with cryopreserved sperm

The objective of this study was to evaluate fertility and full‐term development of rat vitrified oocytes after in vitro fertilization (IVF) with cryopreserved sperm. Oocytes with or without surrounding cumulus cells were vitrified with 30% ethylene glycol + 0.5 mol/L sucrose + 20% fetal calf serum by using the Cryotop method. The warmed oocytes were co‐cultured with sperm. Although the denuded/vitrified oocytes were not fertilized, some of the oocytes vitrified with cumulus cells were fertilized (32.7%) after IVF with fresh sperm. When IVF was performed with cryopreserved sperm, vitrified or fresh oocytes with cumulus cells were fertilized (62.9% or 41.1%, respectively). In addition, to confirm the full‐term development of the vitrified oocytes with surrounding cumulus cells after IVF with cryopreserved sperm, 108 vitrified oocytes with two pronuclei (2PN) were transferred into eight pseudopregnant females, and eight pups were obtained from three recipients. The present work demonstrates that vitrified rat oocytes surrounded by cumulus cells can be fertilized in vitro with cryopreserved sperm, and that 2PN embryos derived from cryopreserved gametes can develop to term. To our knowledge, this is the first report of successful generation of rat offspring derived from vitrified oocytes that were fertilized in vitro with cryopreserved sperm.     

Piezo-assisted in vitro fertilization of mouse oocytes with spermatozoa retrieved from epididymides stored at 4 degree C

This study was performed to investigate the effect of partial zona pellucida incision by piezo micromanipulation (ZIP) on the in vitro fertilizing ability of stored mouse spermatozoa. The storage conditions were optimized by storing the mouse epididymides at 4 C in mineral oil or in the mouse body for up to 4 days after death, and the retrieved spermatozoa were used to fertilize fresh oocytes. No significant difference was observed in fertilization rates between the treatments when epididymides were stored for up to 2 days, but the fertilization rates in mineral oil were higher (P<0.05) than those in the mouse body at 3 (41.4 vs. 16.2%) and 4 days (26.0 vs. 15.8%). Spermatozoa retrieved from epididymides stored in mineral oil were then used to fertilize fresh and vitrified oocytes with or without ZIP treatment. The fertilization rates of the ZIP fresh oocytes were higher than those of the zona-intact oocytes at each time point (1 to 4 days). After ZIP, the fertilization rates of spermatozoa stored for 1 and 2 days (91.2 and 86.6%, respectively) were similar (P>0.05) to that of fresh spermatozoa (91.9%). In regard to vitrified oocytes, the fertilization rates of zona-intact and ZIP oocytes using fresh spermatozoa were 46.7 and 84.7%, while the fertilization rates of vitrified ZIP oocytes using spermatozoa stored for 1 to 4 days ranged from 49.3 to 79.6%. When 2-cell embryos derived from ZIP fresh and vitrified oocytes inseminated with 2 day-stored spermatozoa were transferred into recipient females, 47.9 and 15.0% of the embryos developed to term, respectively. These results indicate that storing mouse epididymides at 4 C in mineral oil is more suitable than storage in the mouse body and that the ZIP technique improves the in vitro fertilizing ability of stored mouse spermatozoa in fresh oocytes and significantly increases the fertilization rate of vitrified oocytes with fresh spermatozoa.     

Boar Sperm Encapsulation Reduces In Vitro Polyspermy

A boar sperm encapsulation technology in barium alginate has been developed to enhance reproductive performances and spermatozoa preservation time; aim of this work was to evaluate the effect of in vitro sperm encapsulation on polyspermy as a function of storage time at 18°C. A total number of 40 in vitro fertilization (IVF) tests were performed using encapsulated or diluted spermatozoa (20 IVF each treatment). Overall, 1288 in vitro matured oocytes were fertilized with spermatozoa stored at 24, 48 or 72 h at 18°C for both treatments polyspermy and normospermy, and the non‐penetration rates were assessed by optical microscopy. Results indicate a significant reduction in risk of polyspermic oocytes when spermatozoa are preserved in barium alginate membranes (incidence risk ratio: 0.766 with respect to diluted); such enhancement could be explained by lesser damage of sperm membranes achieved by encapsulation technology.     

Caffeine in fertilization medium is not essential for bovine IVF by fully capacitated spermatozoa

The purpose of this study was to examine: 1) whether caffeine in the fertilization medium under mineral oil is essential for bovine in vitro fertilization by fully capacitated spermatozoa, 2) the minimum concentration of caffeine that shows an adverse effect on the motility of preincubated spermatozoa. Cumulus-oocyte complexes with heterogeneous-appearing ooplasm were matured in in vitro culture for 24 h and used for insemination. The fertilization rates of the preincubated spermatozoa introduced into the fertilization medium containing 0 mM or 5 mM caffeine were examined. The fertilization rate of the spermatozoa introduced into the medium without caffeine (final concentration of caffeine at fertilization was 0.27-0.35 mM) was significantly higher than that in the medium with 5 mM caffeine (82.4% vs 55.2%, P<0.05). When the final concentration of caffeine at fertilization was reduced ten-fold (0.02-0.03 mM), the fertilization rate was not significantly improved (86.0%). The motility of the preincubated spermatozoa introduced into the fertilization medium containing 0-5 mM caffeine was examined. The sperm motility in the fertilization medium without caffeine was significantly higher than that in the fertilization medium with more than 2 mM caffeine. These results indicate that caffeine in the fertilization medium is not essential for bovine in vitro fertilization by fully capacitated spermatozoa, and that more than 2 mM caffeine has an adverse effect on preincubated (capacitated) sperm motility.     

Effects of Glucose Concentration on in vitro Fertilization in BALB/c Mice

BALB/c mice are widely used in genetic, tumour and immunological studies. However, the mice demonstrate a lower reproduction rate, low fertility and small litters, because of their highly genetic homozygoisty. Based on in vitro fertilization (IVF), a routine technique for biomedical studies, it is worth to evaluate the effects to BALB/c mice on IVF efficiency. In order to test the genetic factor affecting the IVF efficiency of BALB/c, four reciprocal IVF tests of BALB/cByJ and FVB/NCrl mice were performed. The results showed that the average fertility of IVF sponsored by FVB/NCrl spermatozoa was 69.6%, but only 12.1% was obtained from BALB/cByJ strain. Effect of glucose contained in the culture medium to the IVF efficiency of BALB/cByJ was also evaluated. The results showed that the fertility of BALB/cByJ spermatozoa incubated with 0, 2.7, 5.5, 11.1 and 22.2 mm of glucose in the TYH medium were 6.8, 9.9, 13.9, 32.7 and 22.2%, respectively. It is showed that IVF efficiency of BALB/cByJ spermatozoa could be improved depending on the concentration of glucose in the IVF medium. According to the results, it is beleived that lower IVF of BALB/cByJ mice might be due to the genetic defect in spermatozoa and increasing glucose in the IVF medium which significantly affect the IVF efficiency of BALB/cByl via activating the spermatozoa.     

In vitro fertilization and development of in vitro matured bovine follicular oocytes

Bovine follicular oocytes matured in vitro were fertilized in vitro using epididymal spermatozoa from five different bulls and then cultured to the blastocyst stage in vitro. The fertilization rate, based on one pair of pronuclei and presence of one sperm tail, ranged from 55.2 to 64.3%. Embryo development (cleavage to blastocyst stage) ranged from 21.4 to 31.0% of the cultured ova reaching 8 cells at 3 to 4 d after insemination to 1.3 to 3.7% reaching hatched blastocysts at 9 to 10 d. It is concluded that individual variation among bulls is not a significant factor in fertilization and development rates of bovine follicular oocytes when epididymal spermatozoa are used.