Xu Ying, Wang Na, Yu Yang, Li Yang, Li Yan-Bo, Yu Yong-Bo, Zhou Xian-Qing, Sun Zhi-Wei
Department of Health Toxicology and Health Chemistry, School of Public Health, Capital Medical University, Beijing, China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing, China.
Department of Health Toxicology and Health Chemistry, School of Public Health, Capital Medical University, Beijing, China; Department of Laboratory Animal Science, School of Basic Medical Sciences, Capital Medical University, Beijing, China.
PLoS One. 2014 Jul 8;9(7):e101572. doi: 10.1371/journal.pone.0101572. eCollection 2014.
Environmental exposure to nanomaterials is inevitable, as nanomaterials have become part of our daily life now. In this study, we firstly investigated the effects of silica nanoparticles on the spermatogenic process according to their time course in male mice. 48 male mice were randomly divided into control group and silica nanoparticle group with 24 mice per group, with three evaluation time points (15, 35 and 60 days after the first dose) per group. Mice were exposed to the vehicle control and silica nanoparticles at a dosage of 20 mg/kg every 3 days, five times over a 13-day period, and were sacrificed at 15, 35 and 60 days after the first dose. The results showed that silica nanoparticles caused damage to the mitochondrial cristae and decreased the levels of ATP, resulting in oxidative stress in the testis by days 15 and 35; however, the damage was repaired by day 60. DNA damage and the decreases in the quantity and quality of epididymal sperm were found by days 15 and 35; but these changes were recovered by day 60. In contrast, the acrosome integrity and fertility in epididymal sperm, the numbers of spermatogonia and sperm in the testes, and the levels of three major sex hormones were not significantly affected throughout the 60-day period. The results suggest that nanoparticles can cause reversible damage to the sperms in the epididymis without affecting fertility, they are more sensitive than both spermatogonia and spermatocytes to silica nanoparticle toxicity. Considering the spermatogenesis time course, silica nanoparticles primarily influence the maturation process of sperm in the epididymis by causing oxidative stress and damage to the mitochondrial structure, resulting in energy metabolism dysfunction.
由于纳米材料现已成为我们日常生活的一部分，因此不可避免地会出现环境暴露于纳米材料的情况。在本研究中，我们首先根据二氧化硅纳米颗粒在雄性小鼠体内的作用时间进程，研究了其对精子发生过程的影响。48只雄性小鼠被随机分为对照组和二氧化硅纳米颗粒组，每组24只，每组有三个评估时间点（首次给药后15、35和60天）。小鼠每3天接受一次剂量为20 mg/kg的媒介物对照和二氧化硅纳米颗粒处理，在13天内进行5次，在首次给药后15、35和60天处死。结果显示，二氧化硅纳米颗粒导致线粒体嵴损伤并降低ATP水平，在第15天和第35天时导致睾丸氧化应激；然而，到第60天时损伤得到修复。在第15天和第35天时发现DNA损伤以及附睾精子数量和质量下降；但这些变化在第60天时恢复。相比之下，在整个60天期间，附睾精子的顶体完整性和生育能力、睾丸中精原细胞和精子的数量以及三种主要性激素的水平均未受到显著影响。结果表明，纳米颗粒可对附睾中的精子造成可逆性损伤而不影响生育能力，它们比精原细胞和精母细胞对二氧化硅纳米颗粒毒性更敏感。考虑到精子发生的时间进程，二氧化硅纳米颗粒主要通过引起氧化应激和破坏线粒体结构来影响附睾中精子的成熟过程，从而导致能量代谢功能障碍。
