哺乳动物繁殖研究进展

1　直接移植冷冻的绵羊胚胎获得成功应用简单的胚胎冷冻方法 ,并将解冻的胚胎直接移植有助于降低绵羊胚胎移植的成本 ,加速绵羊品种改良。本实验是要研究胚胎冷冻方法在现场应用的可行性。所用的胚胎都从经ＦＳＨ -处理的情期第 7ｄ供体母羊收集 ,并对胚胎进行形态鉴定 ,用改良的ＰＢＳ清洗 ,于 10 %的甘油 ,10 %甘油和 2 0 %乙二醇中分别培养 5ｍｉｎ ,然后移入冷冻液 (2 5 %的甘油和 2 5 %的乙二醇 )中 ,装管 ,并将其移入液氮中冷冻保存。解冻的胚胎或直接移植或按常规方法处理后移植。结果表明 ,冷冻胚胎和新鲜胚胎的妊娠率和存活率没有…     

奶牛生殖激素和体温的性周期变化及调控机制研究进展

随着养殖的集约化程度逐渐提高,传统高耗低效的发情鉴定方法制约了奶牛养殖的经济效益。定时输精技术虽跨越了发情鉴定环节,但未获得理想的受胎率。本文对奶牛卵泡发育过程中生殖激素的变化规律以及雌激素、孕激素、生长因子等对卵泡生长发育的调控作用展开论述,并分析了奶牛体温的性周期变化规律及外源激素对体温的影响,为优化提高同期排卵-定时输精技术及推动奶牛养殖业集约化、智能化、标准化发展提供科学参考。     

哺乳动物体细胞重编程机制的研究进展

体细胞重编程面临的进程缓慢和效率低下等问题,限制了其向临床应用的转化,该过程涉及细胞内基因表达的变化,认识和调控DNA的表观修饰是成功重编程的关键。本文对体细胞重编程过程中基因表达的表观影响以及去分化和转分化的表观控制进行了阐述,并综述了通过表观遗传修饰或信号转导途径增强重编程效率或替代特殊重编程转录因子的物质,不仅有利于阐明体细胞重编程的机制,也为仅采用化学物质即可诱导出多能干细胞的研究提供参考。     

哺乳动物卵泡早期发育调控的研究进展

哺乳动物卵泡发育是一个被众多内分泌、旁分泌和自分泌因素精确调控的生理过程 ,本文结合本试验的研究工作 ,综述了卵泡早期发育调控的研究进展     

抵抗素的生物学作用及调节机制

抵抗素的研究备受关注,是RELMs家族成员,与糖代谢、脂肪代谢、胰岛素抵抗等有很大关系。年龄、性别、营养状况、激素、各种细胞因子都对抵抗素mRNA的表达具有调节作用,奶牛抵抗素的研究目前也受到重视。     

CD36的棕榈酰化对动物脂肪沉积的调控作用及其机制

动物脂肪的过度沉积不仅会降低胴体品质,还会危害动物健康,因此调控动物脂肪沉积对提高产品品质和健康具有重要意义.CD36又称脂肪酸转运酶,可介导脂肪酸的转运和摄取,在脂肪沉积调控中发挥重要作用.棕榈酰化是指16个碳原子的棕榈酸通过硫酯键与蛋白质的氨基酸残基相结合的一种蛋白质翻译后修饰.最新研究表明,CD36的棕榈酰化在脂...     

能量负平衡对奶牛繁殖的影响及相关机理

高产奶牛繁殖力低下是世界性难题。能量负平衡(NEB)影响脂肪动员,改变血液代谢指标,诱发能量代谢紊乱及相关疾病,影响卵泡发育及子宫胚胎内环境,影响机体多种激素的分泌,损害奶牛生殖免疫机能,提高该状态下子宫疾病的易感性并诱发炎症反应,延缓产后子宫恢复,制约奶牛的繁殖性能。本文主要阐述NEB对奶牛繁殖的影响及相关机理,为奶牛生产和繁殖研究工作提供参考。     

蛙皮素样肽调控胰岛素分泌机制研究进展

哺乳动物蛙皮素样肽(BLP)主要包括胃泌素释放肽(GRP)、神经肽C(NMC)和神经肽B(NMB),主要通过GRP-R和NMB-R 2种受体亚型介导生物学效应。其受体BRS-3的内源性配体尚未发现。BLP已经被证明具有促进胰岛素分泌的作用。从组织定位来看,BLP及其受体在胰腺均有分布,其调控胰岛素的分泌主要通过GRP-R介导,其效能与动物的种属、血糖和能量水平有关。BLP可能作为胰腺内神经递质直接促进胰岛β细胞或间接通过激活副交感神经促进胰岛素分泌。BLP还可激活三磷酸肌醇等途径,增加胞外Ca2+内流或者动员胞内钙库,促进胰岛素分泌。BLP对胰岛素分泌的研究不仅补充调控胰岛素分泌机制的理论,也为临床糖尿病的治疗提供新的思路。     

类固醇合成急性调节蛋白的生物学特性及作用研究概况

类固醇合成急性调节蛋白(StAR)是胆固醇的一种转运蛋白,在类固醇激素合成过程中StAR作为限速酶起着特别关键的作用。类固醇激素合成主要在肾上腺、性腺和胎盘等组织中进行,对于维持正常生殖功能和机体内环境的稳定非常重要。有关StAR的发现和特性在以往的文献中已有报道,在此基础上,论文对StAR的生物学特征、作用机制及其与生殖疾病的关系等方面进行综述。     

Intraperitoneal Insemination in Mammals: A Review

This review focuses on factors associated with the development of intraperitoneal insemination in mammals. Findings to date indicate that fertility improves as the sperm cell concentration rises, but that the optimal sperm number differs in each species. Sperm washing before intraperitoneal insemination favours fertility. Peritoneal fluid shows a variable effect on spermatozoa, depending on the hormonal status of the female. The optimal time for insemination appears to be just prior to ovulation. The technique may be performed either through the abdominal or the vaginal wall. Verification of sperm deposition in the proximity of the ovaries improves fertility rates. Although associated with some risk of infection and an immune reaction against spermatozoa, the intraperitoneal technique rarely gives rise to severe anaphylactic shock, peritonitis, adhesion formation and the production of anti‐sperm antibodies and these complications may be prevented by adequate sperm pretreatment and antibiotic therapy. The success of intraperitoneal insemination in humans, with results comparable with those of intrauterine insemination in the treatment of infertility, suggest the potential use of this technique in domestic mammals, especially in those in which intrauterine insemination poses practical difficulties. Some of the methods applied in human intraperitoneal insemination, such as confirming the position of the needle in the peritoneal cavity, and sperm pre‐treatments might also improve results in domestic species. Conversely, the use of the animal model should help to develop some aspects of this technique in humans.     

Mechanisms of Gastrointestinal Ischemia-Reperfusion Injury and Potential Therapeutic Interventions: A Review and Its Implications in the Horse

Restoration of blood flow after a period of intestinal ischemia is necessary to maintain cell function and viability; however, the reintroduction of oxygen can initiate a cascade of events that exacerbates tissue injury. Intestinal I-R injury is manifested as increased microvascular and mucosal permeability, and mucosal necrosis. Reperfusion injury begins with the accumulation of hypoxanthine from ATP metabolism and the conversion of XDH to XO during ischemia. Upon reperfusion, the XO catalyzes the conversion of hypoxanthine to superoxide radicals in the presence of oxygen. Superoxide radicals are further reduced to highly reactive hydroxyl radicals, which initiate lipid peroxidation. Lipoperoxidation causes functional and structural alterations in cell membrane lipids and can release numerous inflammatory mediators, which exacerbate tissue damage. Neutrophils are recruited into tissues during ischemia and on reperfusion; then they undergo degranulation and release destructive products (proteases and OFRs), which mediate further tissue injury. A limited number of experimental studies in the gastrointestinal tract of horses have shown I-R injury. Additional studies are necessary to further elucidate and sequence the precise pathophysiologic mechanisms occuring in the equine intestine during I-R. Therapy should be focused on prevention of I-R injury by pharmacologic or chemical inhibition or modification of these pathophysiologic pathways. Selected pharmacologic agents or drug combinations may offer novel, scientifically relevant and yet practical approaches to alleviating intestinal I-R injury in horses. This may improve survival of horses with naturally acquired intestinal strangulation obstruction.     

Japanese Society for Animal Reproduction: award for outstanding research 2002. Mechanisms controlling neurohypophysial hormone release in the rat

To explore mechanisms of osmotic control of neurohypophysial hormone release, electrical activity of magnocellular neurons (MCNs) in the hypothalamus, related neurons and efferent renal sympathetic nerve activity (RSNA) were recorded from urethane-anesthetized rats. Local osmotic stimulation applied to organum vasculosum of the lamina terminalis (OVLT) or median preoptic nucleus (MnPO) excited MCNs. Although OVLT neurons projected to MCNs were unresponsive to hyperosmotic stimulation, those projected to MnPO and also receiving excitatory inputs from MCNs, were excited by it. MnPO neurons, which were driven by OVLT stimulation and projected to MCNs, were also osmosensitive. Excitatory connections thus exist from MCNs to OVLT, from OVLT to MnPO and from MnPO to MCNs. Neurons in each of these connections were osmosensitive. This circuit thus appears to constitute an osmoreceptor complex essential for the osmoreception of MCNs. MnPO neurons constituting a part of the osmosensitive circuit were also sensitive to hemodynamic change. Thus this circuit may integrate hemodynamic and osmotic information. Local anesthesia of MnPO diminished activation of RSNA and pressor response induced by third cerebroventricular injection of hypertonic saline. The results suggest that the osmosensitive circuit is involved in body fluid regulation not only by controlling vasopressin secretion but also by modulating sympathetic outflow.     

构建《动物繁殖学》开放式实验教学平台培养学生实践创新能力

为进一步提高《动物繁殖学》实验教学质量,充分调动学生的主动性和创新性,提高学生的实验操作技能,培养应用型高素质创新人才,结合多年的实验教学经验和现有实验教学资源,阐述了构建《动物繁殖学》开放式实验教学平台的必要性、存在的问题及建议。