肉碱对冻融猪精子总抗氧化能力、抗氧化酶基因及凋亡相关基因表达的影响

试验旨在探究肉碱对冻融猪精子质量、抗氧化、抗凋亡及精卵结合能力的影响。试验分鲜精组和冻融组，冻融组的肉碱浓度分别为0、0.025、0.05、0.075 mg/mL，对冻融后的精子质量、总抗氧化能力、抗氧化酶相关基因及凋亡相关基因mRNA表达、精卵结合能力进行检测。结果显示，在冻融组中，经过肉碱处理的精子存活率、质膜完整率和顶体膜完整率均显著高于0 mg/mL处理组（P < 0.05），其中肉碱浓度为0.05 mg/mL时改善效果最好；经过冻融处理的精子中丙二醛（MDA）浓度与鲜精组相比显著升高（P < 0.05），其中肉碱浓度为0.05 mg/mL时显著低于其他肉碱处理组（P < 0.05）；与鲜精组相比，各冻融组精子总抗氧化能力均显著降低（P < 0.05），肉碱浓度为0.05 mg/mL时总抗氧化能力最高。此外，与鲜精组相比，0 mg/mL肉碱处理组中凋亡相关基因Caspase-3与Bax的相对表达量显著升高（P < 0.05），抗凋亡基因Bcl-2的相对表达量显著降低（P < 0.05），抗氧化酶相关基因SOD2、CAT与GPx的相对表达量显著降低（P < 0.05）；冻融组精卵结合能力均下降，但肉碱浓度为0.05 mg/mL时可得到显著改善（P < 0.05）。结果表明，添加肉碱可以改善冻融猪精子的质量、抗氧化能力、抗凋亡能力及精卵结合能力。

Effects of Carnitine on Total Antioxidant Capacity and Expression of Antioxidant Enzyme and Apoptosis Related Genes of Frozen-thawed Boar Sperm

This study was aimed to investigate the effects of carnitine on frozen-thawed boar sperm quality,anti-oxidation,anti-apoptosis and sperm-egg fertilization ability in vitro.The sperm was divided into a fresh sperm group and 4 frozen-thawed sperm groups.The frozen-thawed sperm groups were treated with different concentrations of carnitine (0,0.025,0.05 and 0.075 mg/mL).The quality,total antioxidant capacity,sperm-egg binding ability,mRNA expression of antioxidant enzyme related and apoptosis-related genes of sperm were investigated.The results showed that in frozen-thawed groups,carnitine treatment significantly increased sperm motility,plasma membrane integrity rate and acrosome membrane integrity rate compared with 0 mg/mL treatment (P < 0.05),meanwhile treatment with 0.05 mg/mL carnitine showed the highest improvement.The concentration of MDA in sperm was significantly increased after frozen-thaw treatment (P < 0.05),among them,a significant decrease was only measured in 0.05 mg/mL treatment group.Compared with fresh sperm group,the total antioxidant capacity of freeze-thaw group sperm decreased significantly (P < 0.05),0.05 mg/mL carnitine treatment group showed the highest total antioxidant capacity in frozen-thawed groups.Furthermore,compared with fresh sperm group,the relative expression of apoptosis-related genes Caspase-3 and Bax increased significantly (P < 0.05),the relative expression of anti-apoptotic gene Bcl-2 decreased significantly (P < 0.05),and the expression of antioxidant enzyme-related genes SOD2,CAT and GPx decreased significantly in 0 mg/mL carnitine treatment (P < 0.05).Compared with fresh sperm group,the ability of sperm-egg binding in every treatment group showed a decrease,0.05 mg/mL carnitine treatment also showed the highest improvement (P < 0.05).The results indicated that the addition of carnitine could improve the quality,anti-oxidation ability,anti-apoptosis ability and sperm-egg binding ability of frozen-thawed boar sperm.