促卵泡素和表皮生长因子对鸡胚精原细胞增殖的作用

利用精原细胞-体细胞体外无血清共培养模型研究了促卵泡素(FSH)和表皮生长因子(EGF)对鸡胚精原细胞增殖的作用。结果表明:单独的FSH(10～100ng/mL)或EGF(10～100ng/mL)可显著增加精原细胞的数目以及增殖细胞核抗原的表达。EGF(10ng/mL)联合FSH(10ng/mL)具有加性效应,但更高剂量的EGF(100ng/mL)则降低了FSH的促进作用。因此,FSH联合适量的EGF可促进精原细胞的增殖。     

激素及生长因子对牛卵母细胞体外成熟的影响

在卵母细胞体外成熟液(含FSH)中分别添加10, 30, 50ng/mL表皮生长因子(EGF),24h检查其成熟率.结果表明:添加 EGF50ng/mL时牛卵母细胞第一极体排出率显著提高,达85.4%(P＜0.01);同时发现在含FSH和EGF的成熟液中添加HMG(尿促性素)并不能提高牛卵母细胞体外成熟效果(P>0.05);同时还发现单独添加HMG成熟效果显著好于FSH(P＜0.05).     

人尿促性腺激素、雌二醇及表皮生长因子对牛卵母细胞体外成熟质量的影响

试验旨在研究不同激素配比及表皮生长因子(EGF)浓度对牛卵母细胞体外成熟及卵母细胞质量的影响。将随机分组的卵丘-卵母细胞复合体于添加FSH+LH、HMG、FSH+LH+E₂、HMG+E₂ 4种不同激素组合配比的成熟基础液中培养,对比其体外成熟率,比较了EGF对牛卵母细胞体外成熟率和孤雌胚胎体外发育的影响,并采用TUNEL法检测添加不同浓度EGF的牛孤雌激活囊胚细胞凋亡情况。结果表明,添加HMG的成熟试验结果稳定,E₂对牛卵母细胞成熟有一定的促进作用,HMG+E₂联合使用可以得到高效稳定的成熟结果;在此基础上,在成熟液中添加30 ng/mL EGF对牛卵母细胞的成熟质量、胚胎发育及降低胚胎细胞凋亡都有明显的促进作用。因此,在体外成熟培养液中添加0.075 IU/mL HMG、1 μg/mL E₂和30 ng/mL EGF对牛卵母细胞的成熟和质量较为有益。     

不同培养液对牛卵母细胞成熟及核移植效率的影响

在牛卵母细胞成熟液中分别添加促卵泡素(FSH)10μg/L、胰岛素-转铁蛋白-硒(ITS)10μL/mL、表皮生长因子(EGF)10μg/L,配成3种不同体外成熟液对牛卵母细胞进行成熟培养,结果FSH组卵母细胞成熟率84.2%显著高于ITS组75.9%和EGF组70.2%。卵母细胞成熟后构建牛体细胞核移植胚胎,结果FSH、ITS组卵裂率分别为87.2%、81.9%,显著高于EGF组(73.6%),但三组间囊胚率差异不显著(P0.05)。     

表皮生长因子和胰岛素样生长因子对水牛卵母细胞胞质成熟的影响

以皮层颗粒（CG）单层分布于质膜下做为卵母细胞胞质成熟的标志,利用CG荧光染色法,研究了不同浓度表皮生长因子（EGF）和胰岛素样生长因子（IGF-1）及其组合对水牛卵母细胞胞质成熟的影响。结果发现：（1）添加不同浓度的EGF（10、20、30、50ng／mL）都可以提高胞质的成熟率,但是组间差异不显著（P〉0．05）;皮质颗粒的分布随着EGF浓度的升高逐步由中间分布向皮层分布转变;（2）在成熟液中添加IGF-130ng／mL时效果较好,能显著提高卵母细胞胞质的成熟率;皮质颗粒的分布随着IGF-1浓度的升高逐步由中间分布向皮层分布转变,在添加IGF一130ng／mL时,在皮层分布最好,随着IGF-1量的进一步增加,皮质颗粒又向中间分布转变;（3）添加20ng／mL EGF＋30ng／mL IGF-1组卵母细胞体外成熟率高于添加30ng／mL的IGF-1组,显著高于添加20ng／m LEGF组和对照组（P〈0.05）。由此表明,EGF和IGF-1对水牛卵母细胞体外成熟有协同作用。     

水牛卵母细胞在不同培养液中成熟与凋亡的比较研究

为了解卵母细胞体外成熟与凋亡过程,进而提高卵母细胞体外成熟率,本试验研究了在培养液中添加不同浓度的表皮生长因子(EGF)、胰岛素样生长因子-1(IGF-1)对水牛卵母细胞体外成熟和凋亡的影响。结果表明:(1)添加各种浓度的EGF(10,20,30,50,100 ng/mL)均可以提高水牛卵母细胞的成熟率,降低卵母细胞的凋亡率,其中50 ng/mL EGF有显著影响(P<0.05);(2)添加各种浓度的IGF-1(10,30,50,100 ng/mL)均能提高水牛卵母细胞体外成熟率,降低卵母细胞的凋亡率,以30 ng/mL效果明显(P<0.05);(3)添加20 ng/mL EGF+30ng/mL IGF-1组卵母细胞体外成熟率和凋亡率分别高于和低于单独添加IGF-1和EGF组。     

EGF和IGF-1对水牛卵母细胞体外成熟培养的影响

作者研究了在培养液中添加不同浓度的EGF、IGF-1以及EGF联合IGF-1对水牛卵母细胞体外成熟的影响。结果表明：①添加各种浓度的EGF都可以提高水牛卵母细胞的成熟率，其中50 ng/ml EGF有显著影响(P＜0.05)。②10、20 ng/ml的IGF 1对水牛卵母细胞体外成熟无显著影响(P＞0.05)； 30 ng/ml的IGF-1能显著提高水牛卵母细胞体外成熟率(P＜0.05)。③添加20 ng/ml EGF+30 ng/ml IGF-1组卵母细胞体外成熟率高于添加30 ng/ml的IGF-1组，显著高于添加20 ng/ml EGF组和对照组(P＜0.05)。可见，EGF和IGF-1对水牛卵母细胞体外成熟有协同作用。     

牛卵母细胞的体外成熟

在卵母细胞体外成熟液（含FSH）中分别添加10、30、50μg/L表皮生长因子（EGF）,24 h检查成熟率。结果表明,添加10、30μg/L EGF组牛卵母细胞成熟率为79.8%、71.5%与对照组（未添加EGF）成熟率（70.4%）无明显差异（P〉0.05）,但EGF添加至50μg/L时牛卵母细胞第一极体（PB1）排出率显著提高,达85.4%（P〈0.01）;在此基础上,比较了成熟液中添加尿促性素（HMG）对牛卵母细胞体外成熟的影响,结果发现在含FSH和EGF的成熟液中添加HMG未能显著提高牛卵母细胞体外成熟效果（P〉0.05）;最后,比较了HMG对牛卵母细胞体外成熟的效果,结果发现单独添加HMG成熟效果显著高于FSH（P〈0.05）,表明成熟液中如不含其他生长因子,则单独添加HMG较FSH对牛卵母细胞体外成熟的效果好。     

铜对体外仔猪软骨细胞增殖和自分泌IGF—I、IGFBP的影响

体外分离、培养仔猪关节软骨细胞，然后在细胞培养液中分别添加0、7．8、15．6、31．2、62．5μmol/L铜。结果表明，软骨细胞在4种浓度的铜中可存活并增殖，而且能增加胰岛素样生长因子（IGF－I）、胰岛素样生长因子结合蛋白（IGFBP3）的分泌量。但随铜浓度的增加，其存活率、增殖率、^3H-TdR掺入率及IGF－I、IGFBP3的分泌量有明显的差异。且以培养液中添加31．2μmol/L铜对软骨细胞的增殖作用最强，增殖率、^3H-TdR掺入数、IGF－I、IGFBP3的分泌量显著高于对照组9P＜0．01）。表明31．2μmol/L铜浓度是促进体外软骨细胞增殖和自分泌IGF－I、IGFBP3的最适浓度。     

促性腺激素对山羊卵母细胞体外成熟的影响

为了建立针对山羊卵母细胞的理想体外成熟培养体系,本试验研究了在成熟培养液中添加不同浓度的促卵泡素(follicle stimulating hormone,FSH)、促黄体素(luteinizing hormone,LH),不同来源的FSH+LH对山羊卵母细胞体外培养成熟效果的影响。结果表明,采用TCM199添加10%FCS,1～2mg/L17β-E2,10mmol/LHepes,0.055mg/mL丙酮酸钠,2.2mg/mL NaHCO3,500μg/mL链霉素,500μg/mL青霉素,10mg/L FSH及20mg/LLH的培养体系,有利于山羊卵母细胞的体外成熟;进口的和国产FSH和LH对山羊卵母细胞成熟有相同促进效果。     

山羊卵巢无腔卵泡卵母细胞的体外生长

山羊卵巢无腔卵泡卵母细胞在以ＤＭＥＭ为基础,添加ＨＥＰＥＳ（２０ｍｍｏｌ／Ｌ）、ＦＣＳ（１０％）、ＦＳＨ（４０ｍｇ／Ｌ）、次黄嘌呤（２ｍｍｏｌ／Ｌ）、异双丁酰环腺苷酸（２ｍｍｏｌ／Ｌ）、ＩＧＦ－Ｉ（５０μｇ／Ｌ）、氢化可的松（４０μｇ／Ｌ）和ＩＴＳ（５０μｇ／Ｌ）的培养液中得以存活并生长。在二维培养体系中,卵泡在体外的生长模式和体内有很大差别。最显著的特征是卵泡不像在体内那样保持完整的立体结构一直到结束。绝大部分卵泡不同程度地发生基膜溶解和破裂,颗粒细胞向四周扩展并贴壁,形成单层。由于卵泡原有三维立体结构的破坏,易于导致卵母细胞的迁移。在生长方式上以数个卵泡聚集生长对其卵母细胞的生长似乎较为有利。卵泡卵母细胞在体外培养９ｄ,其直径可达１５０μｍ以上,达到了成熟时体积,存活率为５３％。实验证明,山羊无腔卵泡卵母细胞在合适的培养体系中,能在体外存活并生长,并能发育到成熟时的大小。     

Regulation of in vitro growth of preantral follicles by growth factors in goats

Goat preantral follicles were cultured to investigate the effects of insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on the in vitro growth and viability of oocytes. Preantral follicles were isolated mechanically and enzymatically (using collagenase and DNase) from prepuberal goat ovaries. The working medium was composed of Defined Eagle's Minimum Essential Medium (DMEM) supplemented with HEPES (20 mM), 10% fetal calf serum (FCS), hypoxanthine (2 mM), dibutyryl cyclic adenosine 3',5'-monophosphate (dbcAMP) (2 mM), penicillin (75 ng/ml) and streptomycin (50 ng/ml). The culture medium consisted of the working medium with follicle stimulating hormone (FSH) (100 ng/ml) and hydrocortisone (40 ng/ml) added. In the experiment, goat preantral follicles were cultured for 9 days in the culture medium and in the culture medium supplemented with either IGF-I (100 ng/ml), EGF (50 ng/ml), bFGF (50 ng/ml) or IGF-I (100 ng/ml)+EGF (50 ng/ml). The results indicated that IGF-I (100 ng/ml) effectively maintained the survival of oocytes and promoted their growth; EGF (50 ng/ml) enhanced the survival rate of oocytes but had a negative effect on oocyte growth; bFGF (50 ng/ml) stimulated oocyte survival but had no obvious effect on their growth while IGF-I (100 ng/ml) and EGF (50 ng/ml) in combination had a greater effect on both survival and growth rate of oocytes than IGF-I or EGF alone. The supplementation of IGF-1 and EGF to the culture medium is recommended in the culture of goat preantral follicles.     

Impact of Growth Factors on In Vitro Development of Caprine Oocytes at Pre-antral Stage

The objective of this study was to examine the effect of various growth factors such as the epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) either individually or in association, in the presence of follicle-stimulating hormone (FSH) on the in vitro growth and viability of caprine oocytes at pre-antral stage. Pre-antral follicles were disassociated enzymatically and mechanically from pre-pubertal caprine ovaries after the animals were anaesthetically ovariectomized. Caprine pre-antral follicles in group 1, 2, 3 and 4 were cultured in growth culture medium, growth culture medium + EGF, growth culture medium + IGF-I and growth culture medium + IGF-I + EGF, respectively, for 9 days. The results indicated that EGF (50 mg/l) increased the survival rate of oocytes, but decreased the growth rate of oocytes; IGF-I (100 mg/l) effectively maintained the survival of oocytes and stimulated their growth; IGF-I (100 mg/l) and EGF (50 mg/l) in combination produced a higher effect on both the survival and the growth rate of oocytes than IGF-I or EGF alone. Conclusively, the growth factors can effectively maintain the survival of caprine oocytes from pre-antral follicles and regulate their growth in culture. EGF and IGF-I in association could synergically meliorate the culture system of caprine pre-antral follicles.     

The effect of LIF in the absence or presence of FSH on the in vitro development of isolated caprine preantral follicles

We investigated the effect of the leukaemia inhibitory factor (LIF) alone or in association with FSH on the in vitro culture (IVC) of caprine preantral follicles. Preantral follicles >200 μm in size were isolated and cultured for 18 days in basic medium either alone (control) or supplemented with LIF (10 or 50 ng/ml) in the absence or presence of FSH. Every 6 days, follicular survival, growth and antrum formation were evaluated. At the end of the culture period, the oocytes underwent in vitro maturation (IVM), and their viability and chromatin configuration were assessed. Follicles of the control group and those cultured in 10 ng/ml LIF maintained the structural integrity (particularly the preservation of the basement membrane) when compared to the oocytes cultured in 50 ng/ml LIF, regardless the presence of FSH. In the absence of FSH, the percentage of antrum formation after 18 days of culture in the 50 ng/ml LIF group was significantly lower than in either the control group or the 10 ng/ml LIF group. However, this effect was not observed in the presence of FSH. The rate of resumption of meiosis was significantly higher in the 50 ng/ml LIF group in the absence of FSH in comparison with the control and 10 ng/ml LIF groups. Metaphase II was observed only when follicles were cultured in a combination of FSH and 50 ng/ml LIF. In conclusion, LIF alone does not interfere with antral formation and oocyte growth, but at concentration of 50 ng/ml and combined with FSH, it promotes oocyte maturation.     

Effects of EGF and IGF-I on in vitro Maturation and Cleavage of Ovine Oocytes

The study investigated the effects of epidermal growth factor(EGF) and insulin-like growth factor 1(IGF-I),alone or together,on the in vitro maturation and cleavage of ovine oocytes,aimed to optimize the in vitro maturation conditions for ovine oocytes.The results showed that the maturation and cleavage rates were 71.2% and 45.5% respectively when the medium was supplemented with 50 ng/mL EGF alone,which was significantly higher than other EGF supplemented groups (0,10,20,30,and 40 ng/mL) (P<0.05).The highest maturation and cleavage rates were 72.9% and 45.7% when the EGF concentration reached 100 ng/mL.The maturation and cleavage rates were 70.7% and 58.5% with 40 ng/mL IGF-I supplemented,which were significantly higher than other treatments (0,10,20,60,80,and 100 ng/mL) (P<0.05).The lowest maturation and cleavage rates were 38.8% and 20.0% when the IGF-I concentration reached 100 ng/mL (P<0.05).When 50 ng/mL EGF and 40 ng/mL IGF-I were used concomitantly,the maturation and cleavage rates were 85.6% and 61.0% respectively,which were significantly higher than the treatments with EGF or IGF-I alone (P<0.05).     

The final stages of dominant follicle selection in cattle

The final stages of ovarian follicle growth in cattle are typically characterized by the ultrasound-detectable emergence of a cohort of small (3-5mm in diameter) antral follicles, followed by a selection process during which the number of follicles continuing to grow decreases. Finally, only one follicle (the dominant follicle; DF) shows an enhanced growth rate and estradiol synthesis when it attains 8.5mm compared to its closest competitor (the largest subordinate follicle; SF). Cohort emergence is caused by a transient FSH rise, while DF selection occurs during declining FSH indicating differential FSH dependence of DF and SF. In order to elucidate the mechanisms underlying DF survival or SF atresia, this review aims to (i) describe follicular changes in the local production and regulation of members of the inhibin family of proteins and the insulin-like growth factor (IGF) system in relation to FSH deprivation leading to DF selection, and (ii) develop a model for DF selection outlining the putative involvement of inhibins, activin and follistatin on the one hand, and bioavailable IGFs regulated by IGF binding proteins (IGFBPs) and IGFBP proteases on the other hand. It is concluded, that the first indications of differential FSH dependence are seen within 33h of the FSH peak, and high amounts of precursor forms of inhibin and free activin, and low amounts of the lower molecular weight (MW) IGFBPs are related to follicle survival in terms of enhanced growth and estradiol synthesis, and suppression of granulosa cell apoptosis. In addition, maintenance of low amounts of intrafollicular IGFBP4 may constitute an important mechanism in the future DF to attain FSH independence.