牛磺酸对雌性大鼠生殖激素分泌及卵泡发育作用的研究

发布时间：2018-05-09 01:40

  本文选题：牛磺酸 + 下丘脑-垂体-卵巢轴　； 参考：《沈阳农业大学》2015年博士论文

【摘要】：牛磺酸作为人和动物的条件性必需氨基酸,是雌性动物生殖腺和生殖细胞中含量最为丰富的游离氨基酸之一,已有研究证明牛磺酸与卵巢组织发育成熟及雌激素合成分泌密切相关,但其具体机制尚不清楚。本研究以雌性大鼠为试验动物,从mRNA和蛋白水平检测了牛磺酸生物合成关键酶—半胱氨酸双加氧酶(CDO)、半胱亚磺酸脱羧酶(CSD)及牛磺酸转运体(TAUT)在下丘脑-垂体-卵巢轴中的表达；通过牛磺酸饲喂试验,检测了牛磺酸对不同发情周期大鼠生殖激素分泌的影响；采用体外细胞培养技术,检测了牛磺酸对体外培养大鼠下丘脑细胞、垂体细胞、卵巢细胞激素分泌及相关因子表达的影响；通过体外培养卵泡和卵母细胞检测了牛磺酸对卵泡发育、卵母细胞成熟、受精及卵裂的影响,探讨了牛磺酸对雌性生殖机能作用的影响及其可能机制,以期为牛磺酸在女性及雌性动物生殖中的应用提供理论依据。研究结果如下：1.成功克隆出了大鼠下丘脑-垂体-卵巢轴上CSD基因的编码区序列,下丘脑CDO基因的编码区序列,卵巢CDO基因的全长序列及下丘脑-垂体-卵巢轴上TAUT基因的全长序列,且与肝脏中基因的核苷酸序列、氨基酸序列均有较高同源率(96%以上)；下丘脑-垂体-卵巢轴上也存在CSD、CDOTAUT蛋白表达；CDO、CSDTAUT主要分布于卵泡内膜间质细胞层。结果表明：下丘脑、垂体和卵巢能通过CSD通路合成牛磺酸,并具有转运外源牛磺酸入胞的能力。2.牛磺酸对不同发情周期大鼠促性腺激素释放激素(GnRH)、泌乳素(PRL)、促黄体生成素(LH)、雌二醇(E2)和孕酮(P)的分泌均有一定的刺激作用,但对促卵泡刺激素(FSH)分泌的影响不明显。结果表明：牛磺酸可能通过作用于下丘脑-垂体-卵巢轴来调控雌性大鼠的生殖机能。3.牛磺酸能促进体外培养大鼠下丘脑细胞GnRH、腺垂体细胞PRL和LH、卵巢内膜细胞T、颗粒细胞E2和P的分泌；提高内膜细胞中促黄体生成素受体(LHR)、3β-羟基类固醇脱氢酶(3p-HSD)和17p-羟基类固醇脱氢酶(17P-HSD) mRNA的表达,增加颗粒细胞中促卵泡刺激素受体(FSHR)和CYP-19A-1 mRNA的表达。结果表明：牛磺酸可通过增加卵巢中FSHR和LHR的数量,促进性激素合成关键酶的表达来促进雌激素的合成和分泌。4.牛磺酸可促进离体培养卵泡直径增长和E2的分泌；牛磺酸对离体培养卵母细胞MⅡ期形成、受精及卵裂具有促进作用。结果表明：牛磺酸能促进卵泡发育和卵母细胞成熟、受精及卵裂率。本文试验结果表明,大鼠下丘脑-垂体-卵巢轴均可生物合成牛磺酸,而且具有将外源牛磺酸转运入胞的能力；牛磺酸可通过增强下丘脑-垂体-卵巢轴的功能来调控雌性生殖机能。
[Abstract]:Taurine is one of the most abundant free amino acids in the gonads and germ cells of female animals. Studies have shown that taurine is closely related to ovarian tissue maturation and estrogen synthesis and secretion, but its mechanism is not clear. In this study, the expression of cysteine dioxygenase (cysteine dioxygenase), cysteine decarboxylase (cysteine decarboxylase) and taurine transporter (taurine) in hypothalamus-pituitary-ovary axis was detected from mRNA and protein levels in female rats. The effects of taurine on the secretion of reproductive hormones in rats with different estrous cycles were tested by taurine feeding test, and the effects of taurine on rat hypothalamic and pituitary cells in vitro were detected by cell culture technique in vitro. The effects of taurine on follicle development, oocyte maturation, fertilization and cleavage were examined by in vitro culture of follicles and oocytes. The effect of taurine on female reproductive function and its possible mechanism were discussed in order to provide theoretical basis for the application of taurine in female and female animal reproduction. The results are as follows: 1. The coding region sequence of CSD gene on hypothalamus-pituitary-ovary axis, the coding region sequence of CDO gene in hypothalamus, the full-length sequence of CDO gene in ovary and the full-length sequence of TAUT gene on hypothalamus-pituitary-ovary axis were cloned successfully. Moreover, the nucleotide sequence and amino acid sequence of the gene in the liver had a high homology rate of more than 96%, and the expression of CSD- CDOTAUT protein on the hypothalamus-pituitary-ovary axis was mainly distributed in the interstitial layer of the follicular intima. The results showed that the hypothalamus, pituitary and ovary could synthesize taurine via CSD pathway and have the ability of transporting exogenous taurine into cells. Taurine stimulated the secretion of gonadotropin releasing hormone (GnRH), prolactin (PRL), luteinizing hormone (LH), estradiol (E 2) and progesterone (P) in rats with different estrus cycle, but had no obvious effect on follicle stimulating hormone (FSH) secretion. The results showed that taurine may regulate the reproductive function of female rats by acting on hypothalamus-pituitary-ovarian axis. Taurine could promote the secretion of GnRH in rat hypothalamic cells, PRL and LHin adenohypophysis cells, T, E 2 and P in granulosa cells. To increase the expression of luteinizing hormone receptor (LHR3 尾 -hydroxysteroid dehydrogenase 3p-HSD3) and 17p- hydroxysteroid dehydrogenase (17P-HSD) mRNA, and to increase the expression of follicle-stimulating hormone receptor (FSHR) and CYP-19A-1 mRNA in granulosa cells. The results showed that taurine could promote the synthesis and secretion of estrogen by increasing the number of FSHR and LHR in ovary and promoting the expression of key enzymes of sex hormone synthesis. Taurine could increase the diameter of follicle and secretion of E2 in vitro, and taurine could promote the formation of M 鈪，

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