L-肉毒碱对牛精液体外保存时间及品质的影响

Effect of L-carnitine on Sperm Quality and Storage Time of Bovine Semen in Vitro

精液体外孵育保存会使精子品质下降,抗氧化剂L-肉毒碱可促进激活的脂肪酸从细胞质到线粒体基质的转运,减少ROS产生和脂质过氧化反应的发生。研究分析了牛精液体外保存过程中不同浓度L-肉毒碱(LC)(0、2、10和15mmol/L)和不同孵育时间(2、4、6h)对牛精子活力、质膜完整性、线粒体活性和顶体完整性的影响。结果表明:与对照组相比,在牛精液体外保存稀释液中添加10mmol/L和15mmol/L的LC均可显著(P<0.05)提高精子活力(33.0%vs 45.6%,42.4%)、质膜完整率(61.2%vs 73.6%,68.4%)和顶体完整率(81.4%vs 88.4%,86.3%),而线粒体活性则是10 mmol/L LC组效果最好;将筛选的最佳浓度10mM LC组于27℃体外孵育2、4、6h后,其精子的活力、质膜完整率和线粒体高膜电位百分率均显著高于对照组(P<0.05),顶体完整率仅在孵育6h后与对照组差异不显著(P>0.05)。由此可见,LC可保护精子功能和结构免受损伤,不仅能改善牛精液体外保存的品质参数,又可延长牛精液体外保存的时间。

In vitro incubation is known to decrease bovine sperm quality.L-carnitine(LC),a kind of antioxidant,facilitates the transport of activated fatty acids from the cytosol to the mitochondrial matrix.It can reduce reactive oxygen species(ROS)level and the occurrence of lipid peroxidation.In this study,the effect of LC concentration(0,2,10,15 mM)and incubation time(2,4,6 h)on bovine sperm progressive motility,plasma membrane integrity,mitochondrial activity and acrosome integrity was investigated.The result showed that progressive motility(45.6% ,42.4% vs 33.0% ),the percentage of sperm with plasma membrane integrity(73.6% ,68.4% vs 61.2% )and acrosome integrity(88.4% ,86.3% vs 81.4% )of the bovine sperm were higher(P<0.05)for 10 mM and 15 mM LC than those of control,however,mitochondrial activity was the best for 10 mM LC.Furthermore,the progressive motility,the percentage of spermatozoa with plasma membrane integrity and high mitochondrial membrane potential in 10 mM LC groups at 2 h,4 h,6 hwere higher than that in the control(P<0.05).There wasn't significant difference between 10 mM LC and the control on acrosome integrity after 6 hincubation(P>0.05).In conclusion,L-carnitine provided a protection for sperm against in vitro storage-induced functional and structural damages,and improved sperm quality parameters.Meanwhile,it also increased storage time for bovine semen in vitro.