賈振偉

(內蒙古民族大學動物科技學院,黃牛遺傳繁育研究所,內蒙古通遼 028043)

賈振偉

(內蒙古民族大學動物科技學院,黃牛遺傳繁育研究所,內蒙古通遼 028043)

動物卵母細胞含有大量的脂肪酸,脂肪酸通過-氧化能夠為卵母細胞成熟發(fā)育提供能量。許多研究表明,脂肪酸-氧化促進了卵母細胞成熟和受精后早期胚胎發(fā)育?；诖?本文綜述了卵母細胞內脂肪酸的種類、來源,脂肪酸-氧化和調控及其對卵母細胞成熟發(fā)育的影響。

卵母細胞;脂肪酸;-氧化;體外成熟

動物卵母細胞體內生長發(fā)育期間逐漸獲得發(fā)育能力,而且,卵母細胞發(fā)育潛能與自身及周圍的顆粒細胞能量代謝密切相關[1-2]。目前,關于動物卵母細胞葡萄糖、乳酸及丙酮酸等碳水化合物的能量代謝研究較多[3-4],卵母細胞內含有較多數量的脂肪酸,脂肪酸通過-氧化能夠提供大量ATP,但對其在卵母細胞內氧化代謝的研究關注較少。通過對卵母細胞脂肪酸-氧化及其對卵母細胞成熟發(fā)育影響的深入研究,有利于科學合理的調控卵母細胞脂肪酸利用、促進卵母細胞成熟發(fā)育,進而提高動物的繁殖力。

1 卵母細胞脂肪酸的種類及來源

卵母細胞脂肪酸主要以甘油三酯的形式儲存在胞質內的中性脂滴中,另外也以部分磷脂、膽固醇及游離脂肪酸的形式存在。動物卵母細胞及卵泡液內脂肪酸主要為棕櫚酸、硬脂酸、油酸、亞麻酸及亞油酸[5-6]。動物脂肪組織細胞分解釋放或日糧提供的脂肪酸經血液循環(huán)后進入卵泡液被顆粒細胞吸收,顆粒細胞將其酯化為中性脂滴后運轉至卵母細胞,是卵母細胞脂滴的主要來源[7]。值得注意的是,有研究表明,卵母細胞也能將外源的脂肪酸吸收酯化為脂滴的組分,進而影響脂質貯備[8]。

2 卵母細胞脂肪酸β-氧化

Dunning等[9]研究發(fā)現(xiàn),脂肪酸通過-氧化為卵母細胞成熟發(fā)育提供能量。卵母細胞成熟期間脂肪酸-氧化發(fā)生在線粒體內,脂肪酸進入線粒體前在脂酰輔酶A合成酶的作用下被催化成為脂酰輔酶A?；罨闹舅?脂酰輔酶A)在位于線粒體內膜上的肉堿脂酰轉移酶1(CPT1)作用下與肉堿結合后被轉運至線粒體,然后在位于線粒體內膜上的CPT2的作用下除去肉堿,脂肪酸進入線粒體基質后通過-氧化經三羧酸循環(huán)和電子傳遞鏈為卵母細胞成熟發(fā)育提供ATP。

3 卵母細胞脂肪酸β-氧化的調控

此外,Hardie等[15]發(fā)現(xiàn),乙酰輔酶A羧化酶(acetyl coA carboxylase,ACAC)能夠抑制CPT1的活性阻滯活化的脂肪酸進入線粒體,同時促進長鏈脂肪酸合成。但當卵母細胞內AMP/ADP增加時,高濃度的AMP將激活其依賴的蛋白激酶 (AMP-activated protein kinase,AMPK),激活的AMPK通過磷酸化ACAC化使其滅活,促進脂肪酸進入線粒體、增強-氧化。

4 脂肪酸β-氧化對卵母細胞成熟發(fā)育的影響

由于不同物種卵母細胞的脂滴含量存在差異, Paczkowski等[21]比較研究了抑制脂肪酸-氧化對豬、牛及小鼠卵母細胞體外成熟的影響,結果表明,脂肪酸-氧化對卵母細胞核成熟的影響與脂肪酸含量有關。豬和牛卵母細胞脂肪含量較高,較低濃度的CPT1抑制劑阻滯了減數分裂,說明脂肪酸-氧化是其成熟過程必需的代謝通路。小鼠卵母細胞脂肪含量較少,高濃度的CPT1抑制劑能夠阻滯減數分裂,揭示小鼠卵母細胞成熟期間對脂肪酸-氧化代謝通路依賴的程度不如豬和牛等大家畜。而且,Paczkowski等[21]研究也發(fā)現(xiàn),卵母細胞脂肪酸-氧化異常后影響了脂肪酸-氧化、糖酵解及氧化應激相關信號通路基因表達,其中豬和小鼠卵母細胞在脂肪酸-氧化異常的情況下,脂肪酸-氧化、糖酵解及氧化應激相關信號通路基因表達下調,相反牛卵母細胞以上基因表達上調,可能牛卵母細胞存在適應機制。

Paczkowski等[22]研究發(fā)現(xiàn),小鼠卵母細胞脂肪酸-氧化異常后導致脂肪酸-氧化代謝通路相關基因表達下降,同時促進了葡萄糖轉運基因(Glutl)表達,揭示脂肪酸-氧化抑制后可能刺激了葡萄糖的轉運,卵母細胞啟動糖酵解代謝通路滿足成熟期間的能量需要。

5 小結

卵母細胞內含有不同種類的脂肪酸(包括飽和和不飽和脂肪酸),而且這些脂肪酸對卵母細胞成熟發(fā)育的影響存在差異,為優(yōu)化卵母細胞體外成熟體系,卵母細胞體外成熟期間同時補充脂肪酸和L-肉堿對其成熟發(fā)育的影響尚不明確,需要深入研究。

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Research Progress on Beta-Oxidation of Fatty Acids and Its Effect on Oocyte Maturation and Development

JIA Zhen-wei
(Institute of Yellow Cattle Genetics-Breeding and Reproduction,College of Animal Science and Technology,Inner Mongolia University for the Nationalities,Inner Mongolia Tongliao 028000,China)

Animal oocytes contain large amounts of endogenous fatty acid that is capable of generating ATP molecules to support oocyte maturation and development through the process of fatty acid-oxidation.Many researches indicated that fatty acid-oxidation is essential for oocyte maturation and early embryo development.Therefore,this paper reviewed the source and categories of fatty acid,its-oxidation physiological process,some factors regulating its-oxidation,and the effect of promoting its-oxidation on oocyte maturation and development.

oocyte;fatty acids;-oxidation;in viro maturation

S814.2

:A

:0258-7033(2015)13-0090-04

2014-10-16;

2014-11-29

內蒙古民族大學科學研究基金項目(NMDGP1401);內蒙古自治區(qū)自然科學基金項目(2015MS0304)

賈振偉(1974-),男,遼寧營口人,博士,講師,主要從事配子與胚胎生物技術研究,E-mail:zhenwei1999@sina.com