Mishra A, Reddy I J, Gupta P S P, Mondal S
Animal Physiology Division, ICAR-National Institute of Animal Nutrition and Physiology, Bangalore, India.
Reprod Domest Anim. 2016 Apr;51(2):311-21. doi: 10.1111/rda.12682. Epub 2016 Mar 3.
The objective of this study was to find out the effect of L-carnitine on oocyte maturation and subsequent embryo development, with L-carnitine-mediated alteration if any in transcript level of antioxidant enzymes (GPx, Cu/Zn-SOD (SOD1) and Mn-SOD (SOD2) in oocytes and developing sheep embryos produced in vitro. Different concentrations of L-carnitine (0 mm, 2.5 mm, 5 mm, 7.5 mm and 10 mm) were used in maturation medium. Oocytes matured with 10 mm L-carnitine showed significantly (p < 0.05) higher cleavage (66.80% vs 39.66, 41.76, 44.64, 64.31%), morula (48.50% vs 20.88, 26.01, 26.99, 44.72%) and blastocyst (33.22% vs 7.66, 9.19, 10.71, 28.57%) percentage as compared to lower concentrations (0 mm, 2.5 mm, 5 mm and 7.5 mm). Cleavage percentage between 10 mm and 7.5 mm L-carnitine were not significantly different. Maturation rate was not influenced by supplementation of any experimental concentration of L-carnitine. There was a significant (p < 0.05) decrease in intracellular ROS and increase in intracellular GSH in 10 mm L-carnitine-treated oocytes and embryos than control group. Antioxidant effect of L-carnitine was proved by culturing oocytes and embryos with H2O2 in the presence of L-carnitine which could be able to protect oocytes and embryos from H2O2-induced oxidative damage. L-carnitine supplementation significantly (p < 0.05) upregulated the expression of GPx and downregulated the expression of SOD2 genes, whereas the expression pattern of SOD1 and GAPDH (housekeeping gene) genes was unaffected in oocytes and embryos. It was concluded from the study that L-carnitine supplementation during in vitro maturation reduces oxidative stress-induced embryo toxicity by decreasing intracellular ROS and increasing intracellular GSH that in turn improved developmental potential of oocytes and embryos and alters transcript level of antioxidant enzymes.
本研究的目的是探究左旋肉碱对卵母细胞成熟及后续胚胎发育的影响，以及左旋肉碱介导的体外培养的绵羊卵母细胞和发育中的胚胎中抗氧化酶（谷胱甘肽过氧化物酶（GPx）、铜/锌超氧化物歧化酶（SOD1）和锰超氧化物歧化酶（SOD2））转录水平的变化（如有）。在成熟培养基中使用了不同浓度的左旋肉碱（0 mM、2.5 mM、5 mM、7.5 mM和10 mM）。与较低浓度（0 mM、2.5 mM、5 mM和7.5 mM）相比，用10 mM左旋肉碱培养成熟的卵母细胞的卵裂率（66.80% 对39.66%、41.76%、44.64%、64.31%）、桑葚胚率（48.50% 对20.88%、26.01%、26.99%、44.72%）和囊胚率（33.22% 对7.66%、9.19%、10.71%、28.57%）显著更高（p < 0.05）。10 mM和7.5 mM左旋肉碱组之间的卵裂率无显著差异。任何实验浓度的左旋肉碱添加均未影响成熟率。与对照组相比，用10 mM左旋肉碱处理的卵母细胞和胚胎的细胞内活性氧显著减少（p < 0.05），细胞内谷胱甘肽增加。通过在左旋肉碱存在的情况下用H2O2培养卵母细胞和胚胎，证明了左旋肉碱的抗氧化作用，其能够保护卵母细胞和胚胎免受H2O2诱导的氧化损伤。添加左旋肉碱显著上调了GPx的表达（p < 0.05），下调了SOD2基因的表达，而SOD1和GAPDH（管家基因）基因的表达模式在卵母细胞和胚胎中未受影响。该研究得出结论，体外成熟过程中添加左旋肉碱可通过降低细胞内活性氧和增加细胞内谷胱甘肽来降低氧化应激诱导的胚胎毒性，进而提高卵母细胞和胚胎的发育潜力，并改变抗氧化酶的转录水平。
