Kasimanickam R, Kasimanickam V, Thatcher C D, Nebel R L, Cassell B G
Department of Large Animal Clinical Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Theriogenology. 2007 Mar 15;67(5):1004-12. doi: 10.1016/j.theriogenology.2006.11.013. Epub 2006 Dec 22.
Sperm membranes contain high concentrations of polyunsaturated fatty acids that are highly susceptible to oxidative damage that interferes with fertilization ability. The objective of this study was to determine associations among lipid peroxidation (thiobarbituric-acid-reactive substance concentration), antioxidant enzymatic activities in frozen spermatozoa, and competitive indices. Semen from multiple ejaculates collected in succession from each bull (four Holstein and four Jersey) was pooled. Heterospermic doses (20x10(6)sperm/0.5mL straw) were made to obtain 16 Holstein/Jersey combinations (equal number of sperm from each bull). Cows were inseminated on observed or synchronized estrus. The sire of calves (N=460) was determined; based on the number of calves sired, a competitive index was obtained for each bull. Prior to preparation of the heterospermic doses, a sub-sample of semen from each bull was taken, processed, frozen, and stored concurrent with heterospermic samples. After thawing, these homospermic samples were assessed for lipid peroxidation, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, DNA fragmentation index (DFI), plasma membrane integrity (PMI), and total progressive motility (assessed by CASA). Sperm lipid peroxidation and the competitive index were negatively correlated (r=-0.78; P<0.05), the DFI and sperm lipid peroxidation were positively correlated (r=0.86; P<0.001), and there were negative correlations (P<0.05) for sperm lipid peroxidation and both PMI and total progressive motility (r=-0.78 and -0.83, respectively). There was neither significant association between SOD activity and competitive index, nor between GPx activity and competitive index. In conclusion, bulls with lower sperm lipid peroxidation had higher chances of siring calves; this was attributed to the deleterious effects of lipid peroxidation on sperm plasma membrane integrity and sperm DNA, which may reduce sperm fertilizing potential.
精子膜含有高浓度的多不饱和脂肪酸，这些脂肪酸极易受到氧化损伤，从而干扰受精能力。本研究的目的是确定冷冻精子中脂质过氧化（硫代巴比妥酸反应性物质浓度）、抗氧化酶活性与竞争指数之间的关联。从每头公牛（4头荷斯坦牛和4头泽西牛）连续采集的多次射精精液进行混合。制备异精剂量（20×10⁶精子/0.5mL细管）以获得16种荷斯坦牛/泽西牛组合（每头公牛的精子数量相等）。在观察到的发情期或同期发情期对母牛进行授精。确定犊牛（N = 460）的父亲；根据所产犊牛的数量，为每头公牛获得一个竞争指数。在制备异精剂量之前，从每头公牛采集一份精液子样本，进行处理、冷冻，并与异精样本同时储存。解冻后，对这些同精样本进行脂质过氧化、超氧化物歧化酶（SOD）活性、谷胱甘肽过氧化物酶（GPx）活性、DNA片段化指数（DFI）、质膜完整性（PMI）和总渐进性运动能力（通过计算机辅助精子分析评估）的评估。精子脂质过氧化与竞争指数呈负相关（r = -0.78；P < 0.05），DFI与精子脂质过氧化呈正相关（r = 0.86；P < 0.001），精子脂质过氧化与PMI和总渐进性运动能力均呈负相关（P < 0.05）（分别为r = -0.78和-0.83）。SOD活性与竞争指数之间以及GPx活性与竞争指数之间均无显著关联。总之，精子脂质过氧化水平较低的公牛产犊的机会更高；这归因于脂质过氧化对精子质膜完整性和精子DNA的有害影响，这可能会降低精子的受精潜力。
