Effects of purple sweet potato anthocyanins on development and intracellular redox status of bovine preimplantation embryos exposed to heat shock

The development of cleavage stage preimplantation embryos is disrupted by exposure to heat shock, such as high temperatures in the summer season. In this study, we investigated whether addition of anthocyanins, which are strong scavengers of reactive oxygen species (ROS), improves development and intracellular redox status of heat-exposed bovine preimplantation embryos by reduction of heat shock-derived oxidative stress. After in vitro fertilization (IVF), embryos were cultured at 38.5 C through Day 8 (Day 0=day of IVF) with 0, 0.1, 1 and 10 microg/ml anthocyanins (non-heat-shocked group). On Day 2, embryos were cultured at 41.5 C for 6 h with 0, 0.1, 1 and 10 microg/ml anthocyanins followed by culture at 38.5 C until Day 8 (HS group). After exposure to heat shock, the intracellular ROS and glutathione (GSH) contents of individual embryos were measured in the non-heat-shocked and HS groups using fluorescent probes. On Day 8, the blastocysts formation rates of the embryos and total cell numbers of blastocysts were evaluated. Embryos exposed to heat shock without anthocyanins showed a significant decrease in blastocyst formation rate and GSH content (P<0.05) and an increase in intracellular ROS (P<0.05) compared with non-heat-shocked embryos. In contrast, addition of 0.1 microg/ml anthocyanins significantly (P<0.05) improved the blastocyst formation rate of the heat-shocked embryos. Addition of any dose of anthocyanins produced a significant decrease in the ROS levels (P<0.05) and tended to increase the GSH levels under heat-shock conditions. However, addition of higher concentrations (1 and 10 microg/ml) of anthocyanins to the culture media under heat shock did not improve the development of embryos. These results indicate that anthocyanins maintain the intracellular redox balance of heat-shocked bovine embryos by reducing intracellular oxidative stress and increasing the GSH levels. Thus, alterations of the redox state using natural antioxidative polyphenols is a useful approach for reducing heat shock-derived oxidative stress.     

Effects of supplementation of medium with different antioxidants during in vitro maturation of bovine oocytes on subsequent embryo production

The aim of this study was to assess the effects of different antioxidants on the levels of reactive oxygen species (ROS) and glutathione (GSH) in oocytes during in vitro maturation (IVM), as well as on the production of embryos. Oocyte of slaughterhouse‐derived cattle ovaries were placed in IVM with different antioxidants: quercetin (2 μM), cysteamine (100 μM), carnitine (0.5 mg/ml), vitamin C (50 μg/ml) or resveratrol (2 μM). Oocytes matured without any antioxidant supplementation were used as control. The oocytes were assessed for maturation rates and for ROS and GSH levels by fluorescence staining in 2′,7′‐dichlorodihydrofluorescein diacetate and Cell Tracker Blue, respectively. Embryo production was assessed in terms of cleavage, blastocysts and hatching rates and embryo cell numbers. The results expressed in arbitrary fluorescence units showed ROS reduction (p < .05) in the groups with quercetin (27.5 ± 3.4), vitamin C (27.1 ± 3.0) or resveratrol (28.1 ± 4.7), in comparison with those with cysteamine (34.9 ± 4.5), carnitine (34.6 ± 3.8) or to the control group (36.5 ± 5.2). GSH levels increased (p < .05) in cysteamine (63.5 ± 5.5) or carnitine (60.8 ± 4.4) groups in comparison with quercetin (52.7 ± 5.1), vitamin C (53.0 ± 3.8), resveratrol (53.1 ± 4.4) or to the control (49.6 ± 4.5). Nuclear maturation cleavage and hatched blastocysts rates did not differ (p > .05) between groups. However, blastocyst rates after in vitro fertilization in quercetin (53.5 ± 3.9%), vitamin C (52.1 ± 3.1%) resveratrol (54.2 ± 4.0%), cysteamine (52.4 ± 2.7%) or carnitine (54.2 ± 3.1%) groups were higher (p < .05) than in the control (47.2 ± 2.7%). Total cell numbers in embryos from the vitamin C, resveratrol, cysteamine or carnitine groups were higher than in quercetin and control groups, which were similar to each other. The results suggest that using antioxidants during IVM may reduce oxidative stress either by decreasing ROS levels directly or by increasing GSH levels in oocytes, depending on the type of antioxidant used. Overall, oxidative stress control during IVM with the antioxidants examined here improved blastocyst development with similar efficacy.     

Effect of Psammaplin A on in vitro Development of Bovine Aging Oocytes

To investigate the effect of histone deacetylation inhibitor Psammaplin A (PsA) on the development of bovine aging oocytes in vitro,oocytes were randomly divided into control group,aging group and 50 mmol/L PsA treated aging group (PsA group).Immunofluorescence staining and JC-1 were used to detect the blastocyst rate of bovine oocytes after parthenogenetic activation,the number of cells in blastocysts,apoptosis,reactive oxygen species (ROS),glutathione (GSH) and mitochondrial membrane potential intensity of embryos.The results showed that the blastocyst rate of the aging group was significantly lower than that of PsA and control groups (P<0.05).The blastocyst rate of PsA group was not significantly different from that of control group (P>0.05).The number of cells in the blastocysts of control group and PsA group were significantly higher than that of aging group (P<0.05).The number of cells in the blastocysts of PsA group was not significantly different from that of control group (P>0.05).The apoptosis rate in aging group was significantly higher than that of control and PsA groups (P<0.05),the apoptosis rate of PsA group was significantly higher than that of control group (P<0.05).The GSH level of MⅡ oocytes in aging group was significantly lower than that of control and PsA groups (P<0.05).There was no significant difference in GSH level between control and PsA groups (P>0.05).The ROS level of the embryos in aging group was significantly higher than that of control and PsA groups (P<0.05).The ROS level in PsA group was significantly higher than that of control group (P<0.05).The mitochondrial membrane potential of early embryos of aging group 4-8 cells was significantly lower than that of control and PsA groups (P<0.05).The mitochondrial membrane potential intensity of control group was significantly higher than that of PsA group (P<0.05).In summary,PsA could effectively delay the aging of bovine oocytes and improve the quality of oocytes.     

芝麻素对小鼠早期胚胎体外发育的影响

本试验旨研究在体外培养（in vitro culture，IVC）中添加芝麻素（sesamin，SES）对小鼠早期胚胎体外发育的影响。采集6周龄雌性昆明小鼠受精卵，随机分为对照组和不同浓度（10、50、100 μmol/L）SES组。采用Fluorescein-dUTP和Hoechst 33342免疫荧光染色分别检测囊胚内细胞凋亡率和总细胞数；采用DCFH-DA检测早期胚胎内活性氧（reactive oxygen species，ROS）水平；采用CMF₂HC检测早期胚胎内谷胱甘肽（glutathione，GSH）水平；采用JC-1检测早期胚胎线粒体膜电位强度。结果显示，不同浓度SES组分裂率和囊胚率较对照组均有提高，但无显著差异（P>0.05）；50 μmol/L SES组细胞数较对照组显著提高（P<0.05），细胞凋亡率较对照组显著降低（P<0.05）；与对照组相比，50 μmol/L SES组ROS水平显著降低（P<0.05），GSH水平和线粒体膜电位水平显著提高（P<0.05）。结果表明，在IVC中添加SES可提高囊胚内细胞数、减少细胞凋亡率，降低细胞内ROS水平，提高细胞内GSH水平，改善早期胚胎线粒体功能，减少胚胎氧化应激的损伤，提高小鼠早期胚胎发育质量。     

Oxidative stress and redox regulation on in vitro development of mammalian embryos

Many factors affect development of mammalian preimplantation embryos in vitro. It is well known that in vitro development of bovine embryos is highly affected by culture condition including energy source, growth factors, pH or gas environment. Many efforts have been made towards the suitable environments which can successfully support embryo development in vitro. For a rapid growth and differentiation, embryo requires energy by utilizing ATP, NADPH with oxygen molecules. These energy substrates are produced from the electron transport chain in the mitochondria. In addition to energy production, reactive oxygen species (ROS) are also generated as by-product of such energy production system. ROS production is sensitively controlled by the balance of oxidizing and reducing status and affected by several antioxidant enzymes such as superoxide dismutase (SOD), Catalase, glutathione peroxidase (GPx) or low molecular weight thiols such as glutathione (GSH). Imbalance of oxidation and reduction causes production of excess ROS, which causes the developmental arrest, physical DNA damage, apoptosis induction or lipid peroxidation. Environmental oxygen condition during embryo culture also highly affects embryo development as well as intracellular redox balance. Several studies have revealed that regulation of intra- and extra- cellular reducing environment by reducing excess ROS by using antioxidants, reducing oxygen concentration are effective for improving embryo development. Also, recent studies have demonstrated the difference in gene expression affected by oxidative stress. This review briefly summarizes the effects of ROS and the role of redox balance on preimplantation embryos for improving the efficiency of in vitro production of mammalian embryos.     

α-硫辛酸抗氧化作用机制及其在动物生殖细胞和早期胚胎中抗氧化作用的研究进展

活性氧(ROS)引起的氧化应激是动物生殖细胞和早期胚胎发生凋亡或永久性发育阻滞的主要原因之一。因此,在体外培养系统中添加抗氧化剂成为降低氧化应激对动物生殖细胞损伤和提高早期胚胎发育能力的方法之一。α-硫辛酸(LA)作为一种强抗氧化剂,可以通过直接清除自由基、螯合金属离子并促进其他抗氧化物质形成从而发挥抗氧化作用。在生殖细胞和早期胚胎中,LA可以通过降低ROS水平、促进抗氧化酶活性和线粒体活性来提高生殖细胞质量和早期胚胎发育能力。本文概述了LA抗氧化作用机制及其在动物生殖细胞和早期胚胎发育过程中抗氧化作用的研究进展,为进一步探究LA抗氧化作用的分子机制提供理论依据和研究思路。     

Effect of Antioxidants During Bovine In Vitro Fertilization Procedures on Spermatozoa and Embryo Development

Increased amounts of reactive oxygen species (ROS) during in vitro fertilization (IVF) may cause cytotoxic damage to gametes, whereas small amounts of ROS favour sperm capacitation. The aim of this study was to investigate the effect of antioxidants [50 μ m β-mercaptoethanol (β-ME) and 50 μ m cysteamine (Cyst)] or a pro-oxidant (5 m m buthionine sulfoximine) on the quality and penetrability of spermatozoa into bovine oocytes and on the subsequent embryo development and quality when added during IVF. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes, and mitochondrial function, was diminished (p < 0.05) after 4-h culture in the presence of antioxidants. Oocyte penetration rates were similar between treatments (p > 0.05), but antioxidants adversely affected the normal pronuclear formation rates (p < 0.05). The incidence of polyspermy was high for β-ME (p < 0.05). No differences were observed in cleavage rates between treatments (p > 0.05). However, the developmental rate to the blastocyst stage was adversely affected by Cyst treatment (p < 0.05). The quality of embryos that reached the blastocyst stage, evaluated by total, inner cell mass (ICM) and trophectoderm cell numbers and ICM/total cell ratio was unaffected (p > 0.05) by treatments. The results indicate that ROS play a role in the fertilizing capacity in bovine spermatozoa, as well as in the interaction between the spermatozoa and the oocytes. It can be concluded that supplementation with antioxidants during IVF procedures impairs sperm quality, normal pronuclear formation and embryo development to the blastocyst stage.     

bFGF对3-硝基丙酸处理的小鼠受精卵体外发育能力的影响

【目的】 研究在体外培养液中添加碱性成纤维细胞生长因子(bFGF)对3-硝基丙酸(3-NPA)处理的小鼠受精卵体外发育能力的影响, 为提高氧化应激早期胚胎体外发育质量提供参考。【方法】 在小鼠受精卵体外培养液中添加0、20、50、100和150 ng/mL bFGF, 培养24、48和96 h, 统计2-细胞率、4-细胞率和囊胚率, 筛选最佳bFGF处理浓度。经腹腔注射12.5 mg/kg 3-NPA生产氧化应激体内受精卵, 正常组小鼠腹腔注射等体积生理盐水, 将获得的受精卵分为添加或不添加bFGF组, 即3-NPA和3-NPA+bFGF组及对照组(C)和bFGF组, 培养到囊胚后, 用DCFH-DA检测胚胎内活性氧(reactive oxygen species, ROS)水平, CMF2HC检测谷胱甘肽(glutathione, GSH)水平, JC-1检测早期胚胎线粒体膜电位强度。【结果】 0、20、50、100和150 ng/mL bFGF组2-细胞率均无显著差异(P>0.05), 100 ng/mL bFGF组囊胚率显著高于其他各组(P<0.05), 150 ng/mL bFGF组4-细胞率和囊胚率均显著低于其他各组(P<0.05), 因此后续试验选用100 ng/mL bFGF。3-NPA+bFGF组4-细胞率显著高于3-NPA组(P<0.05), bFGF组囊胚率显著高于其他组(P<0.05)。bFGF+3-NPA组囊胚率显著高于3-NPA组(P<0.05);与对照组相比, 3-NPA组ROS水平显著升高(P<0.05), bFGF组ROS水平显著降低(P<0.05);3-NPA组GSH和线粒体膜电位水平均显著降低(P<0.05), bFGF组GSH和线粒体膜电位水平均显著增加(P<0.05)。bFGF+3-NPA组ROS水平显著低于3-NPA组(P<0.05), GSH和线粒体膜电位水平均显著高于3-NPA组(P<0.05)。【结论】 在体外培养液中添加100 ng/mL bFGF可减少3-NPA诱导的胚胎氧化应激、改善胚胎线粒体功能, 从而提高小鼠受精卵体外发育的能力。     

3,4-Dihydroxyflavone acts as an antioxidant and antiapoptotic agent to support bovine embryo development in vitro

The effects of two antioxidants, superoxide dismutase (SOD) and the flavonoid 3,4-dihydroxyflavone (DHF), on bovine embryo development in vitro were examined. Blastocyst development, total cell and inner cell mass (ICM) numbers, intracellular levels of reactive oxygen species (ROS), apoptotic indices and gene expression levels were examined before and after treatment of day 2 bovine embryos (≥2-4 cells) with various concentrations of 3,4-DHF or SOD for 6 days. Statistical analysis was performed using analysis of variance, with significance defined at the P<0.05 level. SOD had no significant effect on bovine embryo development at any tested concentration (control, 32.8%; 300 U/ml, 33.9%; 600 U/ml, 24.2%). In contrast, 10 μM 3,4-DHF promoted higher blastocyst development (39.3%) than any other concentration (control, 26.7%; 1 μM, 30.3%; 50 μM, 29.5%; 100 μM, 20.5%). Compared with 300 U/ml SOD, 10 μM 3,4-DHF resulted in significantly higher blastocyst development (44.2%) (control, 31.5%; SOD 300 U/ml, 33.6%). Treatment with 3,4-DHF increased the ICM cell number and reduced intracellular ROS production and apoptotic cell numbers. When O(2) tension was decreased from 20% (high tension) to 5% (low tension), embryo development rates were doubled regardless of 3,4-DHF treatment. Under high O(2) tension, 10 μM 3,4-DHF treatment may render bovine embryo development similar to a low O(2) tension environment. The best blastocyst development was obtained under low O(2) tension plus 10 μM 3,4-DHF treatment. The relative expression levels of antioxidant (MnSOD), antiapoptotic (Survivin, Bax inhibitor) and growth-related genes (IFN-τ, Glut-5) were significantly increased after 3,4-DHF treatment, while the expression levels of oxidant (Sox) and apoptotic genes (Caspase-3 and Bax) were reduced. These results suggest that 3,4-DHF may promote the in vitro development of bovine embryos through its antioxidant and antiapoptotic effects.     

Improved development of ICR mouse 2-cell embryos by the addition of amino acids to a serum-, phosphate-and glucose-free medium

This study was conducted to evaluate how exogenous amino acids could affect preimplantation development of ICR mouse embryos. Two-cell embryos collected from naturally mated mice were cultured in amino acid-, glucose- and phosphate-free preimplantation (P)-1 medium. In Experiments 1, 19 amino acids (aa; 1% and 0.5% of MEM essential and nonessential amino acid solutions, respectively) were added to P-1 medium supplemented with either fatty acid-free bovine serum albumin (BSA; 3 mg/mL) or human follicular fluid (hFF; 10%). Regardless of BSA or hFF addition, embryo development to the morula (84 to 86% vs. 97 to 100%) and the blastocyst (54% vs. 93 to 94%) stages was significantly (P<0.05) enhanced by the addition of aa compared with no addition. In Experiment 2, the cell number of blastomeres and inner cell mass (ICM) cells in blastocysts and the ratio of ICM cell to trophectodermal cell (TE) were evaluated after aa addition. In both BSA- and hFF-containing P-1 medium, a significant increase in total blastomere number were found after aa addition (47 to 52 vs. 62 to 63 cells) compared with no addition. However, the ICM/TE ratio was not significantly affected by aa supplementation in both media, while ICM cell number was greatly increased after aa addition in hFF-containing medium (12 vs. 17 cells). When blastocysts were further cultured up to 162 hr post-hCG injection, development to the hatched blastocyst stage was significantly promoted by aa addition (0% vs. 11 to 20%) in both BSA- and hFF-containing media. In conclusion, aa significantly promote the preimplantation development to the hatched blastocyst stage and such effect mainly exerted on supporting blastomere proliferation.     

Requirement for nuclear autoantigenic sperm protein mRNA expression in bovine preimplantation development

Nuclear autoantigenic sperm protein (NASP) is associated with DNA replication, cell proliferation, and cell cycle progression through its specific binding to histones. The aim of this study was to examine the roles of NASP in bovine preimplantation embryonic development. Using NASP gene knockdown (KD), we confirmed the reduction of NASP messenger RNA (mRNA) expression during preimplantation development. NASP KD did not affect cleavage but significantly decreased development of embryos into the blastocyst stage. Furthermore, blastocyst hatching was significantly decreased in NASP KD embryos. Cell numbers in the inner cell mass of NASP KD blastocysts were also decreased compared to those of controls. These results suggest that NASP mRNA expression is required for preimplantation development into the blastocyst stage in cattle.     

Significance of CCN2 expression in bovine preimplantation development

In mammalian preimplantation development, the first cell lineage segregation occurs during the blastocyst stage, when the inner cell mass and trophectoderm (TE) differentiate. Species‐specific analyses are essential to elucidate the molecular mechanisms that underlie this process, since they differ between various species. We previously showed that the reciprocal regulation of CCN2 and TEAD4 is required for proper TE differentiation in bovine blastocysts; however, the function of CCN2 during early embryogenesis has remained otherwise elusive. The present study assessed the spatiotemporal expression dynamics of CCN2 in bovine embryos, and evaluated how changes to CCN2 expression (using a CCN2 knockdown (KD) blastocyst model) regulate the expression of pluripotency‐related genes such as OCT4 and NANOG. The conducted quantitative PCR analysis revealed that CCN2 mRNA was expressed in bovine oocytes (at the metaphase stage of their second meiosis) and embryos. Similarly, immunostaining detected both cytoplasmic and nuclear CCN2 at all analyzed oocyte and embryonic stages. Finally, both OCT4 and NANOG expression levels were shown to be significantly reduced in CCN2 KD blastocysts. Together, these results demonstrate that bovine CCN2 exhibits unique expression patterns during preimplantation development, and is required for the proper expression of key regulatory genes in bovine blastocysts.     

Stress exposure during the preimplantation period affects blastocyst lineages and offspring development

We found retardation of preimplantation embryo growth after exposure to maternal restraint stress during the preimplantation period in our previous study. In the present study, we evaluated the impact of preimplantation maternal restraint stress on the distribution of inner cell mass (ICM) and trophectoderm (TE) cells in mouse blastocysts, and its possible effect on physiological development of offspring. We exposed spontaneously ovulating female mice to restraint stress for 30 min three times a day during the preimplantation period, and this treatment caused a significant increase in blood serum corticosterone concentration. Microscopic evaluation of embryos showed that restraint stress significantly decreased cell counts per blastocyst. Comparing the effect of restraint stress on the two blastocyst cell lineages, we found that the reduction in TE cells was more substantial than the reduction in ICM cells, which resulted in an increased ICM/TE ratio in blastocysts isolated from stressed dams compared with controls. Restraint stress reduced the number of implantation sites in uteri, significantly delayed eye opening in delivered mice, and altered their behavior in terms of two parameters (scratching on the base of an open field test apparatus, time spent in central zone) as well. Moreover, prenatally stressed offspring had significantly lower body weights and in 5-week old females delivered from stressed dams, fat deposits were significantly lower. Our results indicate that exposure to stress during very early pregnancy can have a negative impact on embryonic development with consequences reaching into postnatal life.     

Different Culture Media Requirements of IVF and Nuclear Transfer Bovine Embryos

Important differences exist between in vitro fertilized (IVF) and nuclear transfer (NT) bovine embryos. Studies have shown that although in vitro development is comparable, post-implantation survival is greatly reduced in NT embryos. In this study, we compare serum and bovine serum albumin (BSA) supplementation during oocyte maturation and embryo culture of IVF and NT embryos. In experiment 1, oocytes and embryos were randomly distributed into different treatment groups consisting of synthetic oviductal fluid (SOF) medium supplemented with either serum, fatty acid-free BSA (FAF) or fraction V BSA during maturation and/or culture to assess IVF embryo development. In experiment 2, oocytes were matured in SOF + serum or SOF + FAF and reconstructed embryos were cultured in SOF + FAF to assess NT embryo development. Among the IVF treatment groups, a greater number of blastocysts were observed in the steer serum (SER) group (IVM and IVC in SOF + serum) on day 6; however, no significant differences were seen in blastocyst development from day 8 onwards. Hatching frequencies on days 8 and 9 were significantly greater in groups with serum, with the exception of FAF (IVM and IVC in SOF + FAF) on day 9. For the NT treatment groups, the presence of serum during IVM resulted in a higher proportion of MII oocytes and increased blastocyst development and hatching rates were compared with supplementation of FAF. These results indicate that both serum and FAF provide comparable embryo development for IVF but not for NT bovine embryos.     

Antioxidant response element activator,BTZO-1, improves the developmental competence of bovine oocytes

Increased reactive oxygen species (ROS) generation may disrupt the oocytes function and their competence. In this study, we introduced BTZO-1, a new supplement that can regulate the oxidative stress. Addition of BTZO-1 during IVM of bovine oocytes improved their developmental competence in the term of improvement of blastocyst rates. In addition, the quality of the produced embryos was improved by decreasing the apoptosis level by showing a decreased number of TUNNEL positive cells.     

牛体外受精早期胚胎与小鼠胎仔成纤维细胞共培养的研究

探讨了人工合成培养液ＣＲ１ａａ和小鼠胎仔成纤维细胞对牛体外受精早期胚胎体外发育的影响。结果表明，牛体外受精卵在ＣＲ１ａａ液中的卵裂率达７６．２％，８细胞胚的比率达４４．８％。小鼠胎仔成纤维细胞能够显著促进牛体外受精的早期囊胚以上胚胎的发育。牛体外受精后第５、６天的早期胚胎分别与小鼠胎仔成纤维细胞共培养，在受精后第７天发育至囊胚以上的比率分别达１９．８％和２４．６％；受精后第８天，孵化的囊胚比例分别达５．２％和７．５％。实验表明，受精后第５、６天的牛体外受精早期胚胎与小鼠胎仔成纤维细胞共培养，可显著提高扩张囊胚和孵化囊胚数量。小鼠成纤维细胞对胚胎发育的支持作用取决于胚胎发育阶段     

柠檬苦素对小鼠卵母细胞体外成熟及其体外受精胚胎发育的影响

【目的】研究柠檬苦素(limonin,Lim)对小鼠卵母细胞体外成熟(IVM)及后续体外受精(IVF)胚胎发育潜能的影响,旨在为体外成熟培养系统的优化提供参考。【方法】在小鼠体外成熟培养液中添加不同浓度的Lim(0、10、20、50 μmol/L),成熟培养12 h后统计小鼠卵母细胞第一极体(PBI)排出率,筛选体外成熟培养液中添加Lim的最适浓度;在体外成熟培养液中添加最适浓度的Lim,以0 μmol/L Lim为对照组,成熟培养12 h,通过免疫荧光染色检测活性氧(ROS)、谷胱甘肽(GSH)以及线粒体膜电位(MMP)水平;通过实时荧光定量PCR检测卵母细胞抗氧化及凋亡相关基因的mRNA表达水平。将最适Lim组及对照组卵母细胞体外成熟24 h后进行体外受精,于体外受精24 h和3.5 d分别统计胚胎卵裂率和囊胚率,并用Fluorescein-dUTP和Hoechst 33342染色分别检测囊胚总细胞数及囊胚内凋亡细胞比率。【结果】与0 μmol/L Lim组相比,20 μmol/L Lim组小鼠卵母细胞PBI排出率显著升高(P＜0.05),后续试验均用20 μmol/L Lim进行处理。与对照组组相比,20 μmol/L Lim组小鼠卵母细胞内ROS水平显著降低(P＜0.05),GSH、MMP水平均显著增加(P＜0.05),抗氧化相关基因(GPx3、CAT和Prdx3)、抗凋亡相关基因(Bcl-2、Bcl-xl)表达水平均显著上调(P＜0.05),促凋亡相关基因(Caspase-3)表达水平显著下调(P＜0.05);体外受精胚胎的卵裂率、囊胚率、囊胚总细胞数均显著增加(P＜0.05),囊胚内细胞凋亡比率显著下降(P＜0.05)。【结论】在体外成熟培养液中添加20 μmol/L Lim可以通过抑制氧化应激和细胞凋亡、增加MMP水平提高小鼠卵母细胞质量,从而提高体外受精胚胎的发育潜力。     

黄牛卵母细胞和早期胚胎组蛋白乙酰化转移酶1表达模式研究

为探讨卵母细胞成熟及早期胚胎发育过程中组蛋白乙酰基转移酶(HAT1)的表达规律,研究应用实时定量PCR技术,检测了广西本地黄牛卵母细胞和附植前胚胎HAT1基因的表达情况。结果表明:HAT1基因在黄牛生发泡期(GV)卵母细胞、第2次减数分裂中期(MⅡ)卵母细胞、体外受精(IVF)胚胎2～4细胞、8～16细胞、桑葚胚和囊胚中的相对表达量分别为1.00、0.56、0.08、0.55、0.43和0.31,在孤雌激活(PA)胚胎的2～4细胞、8～16细胞、桑葚胚和囊胚中的相对表达量分别为0.55、0.55、0.48和0.46。HAT1在GV期相对表达量最高,在IVF胚胎中2～4细胞表达量最少(P<0.05)。由此可见,HAT1基因在黄牛卵母细胞成熟和早期胚胎阶段均有表达,GV期HAT1基因的表达最高,PA胚胎HAT1基因的表达较稳定。