Fu Long-Long, Zhang Lin-Yuan, An Qi, Zhou Fang, Tong Yue, Guo Ying, Lu Weng-Hong, Liang Xiao-Wei, Chang Bing, Gu Yi-Qun
Graduate School, Peking Union Medical College, Beijing 100730, China.
Human Sperm Bank, Research Institute of the National Health and Family Planning Commission for Family Planning Science and Technology / Clinical Laboratory of Male Health / Key Laboratory of the National Health and Family Planning Commission for Male Reproductive Health, Beijing 100081, China.
Zhonghua Nan Ke Xue. 2018 Dec;24(12):1059-1063.
To study the effects of L-carnitine (LC) on cryopreserved human sperm.
Ten semen samples were collected from normal sperm donors, each divided into six groups, fresh ejaculate (FE), non-LC cryopreservation (non-LC), and cryopreservation with LC at 1 mmol/L (LC-1), 2.5 mmol/L (LC-2), 5 mmol/L (LC-3) and 10 mmol/L (LC-4), respectively. The optimal concentration of LC was identified based on the motility and motion parameters of the post-thaw sperm. The plasma membrane integrity (PMI) of the sperm was assessed by eosin-nigrosin staining, their mitochondrial membrane potential (MMP) monitored by JC-1 assay, and the level of sperm ROS measured by the fluorescent probe DCFH-DA, followed by analysis of the mechanisms of LC protecting sperm against cryopreservation injury.
Compared with the sperm in the FE group, the post-thaw sperm in the non-LC and LC groups showed significantly decreased progressive motility, average path velocity (VAP), straight line velocity (VSP) and curvilinear velocity (VCP) (P < 0.05). In comparison with the non-LC group, the LC-3 group exhibited a remarkably higher percentage of progressively motile sperm (［41.9 ± 4.6］ vs ［47.0 ± 4.3］%, P = 0.0261) and VAP (［34.9 ± 2.6］ vs ［38.9 ± 4.2］ μm/s, P = 0.0152), indicating that the optimal concentration of LC was 5 mmol/L. Both PMI and MMP were significantly lower in the non-LC than in the FE group (［52.7 ± 5.7］ vs ［75.5 ± 5.4］%, P < 0.01 and ［44.5 ± 3.5］ vs ［57.3 ± 4.4］%, P < 0.01), but higher in the LC groups (［70.1 ± 8.2］% and ［50.3 ± 3.4］%) than in the non-LC group (P < 0.01 and P < 0.05). The level of sperm ROS, however, was markedly higher in the non-LC than in the FE group (［12.5 ± 3.9］ vs ［6.8 ± 2.4］, P < 0.01) but lower in the LC groups (［8.4 ± 5.3］%) than in the non-LC group (P = 0.05).
L-carnitine can improve the motility and motion parameters of cryopreserved human sperm by reducing sperm ROS, enhancing sperm mitochondrial membrane potential and protecting the sperm plasma membrane.
研究左旋肉碱（LC）对冷冻保存的人类精子的影响。
从正常精子捐献者中收集10份精液样本，每份样本分为6组，即新鲜射精样本（FE）、无LC冷冻保存组（无LC）、以及分别添加1 mmol/L（LC-1）、2.5 mmol/L（LC-2）、5 mmol/L（LC-3）和10 mmol/L（LC-4）LC的冷冻保存组。根据解冻后精子的活力和运动参数确定LC的最佳浓度。通过伊红 - 黑色素染色评估精子的质膜完整性（PMI），通过JC-1检测监测其线粒体膜电位（MMP），并用荧光探针DCFH-DA测量精子ROS水平，随后分析LC保护精子免受冷冻保存损伤的机制。
与FE组精子相比，无LC组和LC组解冻后的精子在渐进性活力、平均路径速度（VAP）、直线速度（VSP）和曲线速度（VCP）方面均显著降低（P < 0.05）。与无LC组相比，LC-3组的渐进性活动精子百分比显著更高（［41.9 ± 4.6］% 对 ［47.0 ± 4.3］%，P = 0.0261），VAP也更高（［34.9 ± 2.6］对 ［38.9 ± 4.2］μm/s，P = 0.0152），表明LC的最佳浓度为5 mmol/L。无LC组的PMI和MMP均显著低于FE组（［52.7 ± 5.7］% 对 ［75.5 ± 5.4］%，P < 0.01和［44.5 ± 3.5］% 对 ［57.3 ± 4.4］%，P < 0.01），但LC组（［70.1 ± 8.2］% 和 ［50.3 ± 3.4］%）高于无LC组（P < 0.01和P < 0.05）。然而，无LC组的精子ROS水平显著高于FE组（［12.5 ± 3.9］对 ［6.8 ± 2.4］，P < 0.01），但LC组（［8.4 ± 5.3］%）低于无LC组（P = 0.05）。
左旋肉碱可通过降低精子ROS、增强精子线粒体膜电位和保护精子质膜来改善冷冻保存的人类精子的活力和运动参数。
