Hernández-Ochoa I, Sánchez-Gutiérrez M, Solís-Heredia M J, Quintanilla-Vega B
Sección Externa de Toxicología, CINVESTAV, Ave. IPN #2508, Colonia Zacatenco, Mexico City 07360, Mexico.
Reprod Toxicol. 2006 Feb;21(2):171-8. doi: 10.1016/j.reprotox.2005.07.015. Epub 2005 Sep 29.
Lead (Pb) alters sperm chromatin condensation (CC) and the mechanisms are investigated. During spermatogenesis, protamines replace histones and disulfide bonds formation during epididymal maturation condense the chromatin. We evaluated sperm Pb uptake in testis and epididymis and the effects on CC in mice (0.06% Pb(2+)/16 weeks/drinking water). Spermatozoa from caput epididymis (CP) and cauda epididymis-vas deferens (CE-VD) were obtained and CC was measured by SCSA. Lead levels in spermatozoa from CP were lower than those from CE-VD, and correlated with a decreased CC, while Pb in CE-VD spermatozoa correlated with an increased CC. Lead accumulation into the nucleus was observed and Pb binding to nuclear sulfhydryl groups decreased chromatin decondensation in vitro. Our results suggest that spermatozoa take up Pb during testicular development and epididymal transport and alter CC, depending of the timing of Pb incorporation into the sperm nucleus, which finally may interfere with the chromatin decondensation process after fertilization.
铅（Pb）会改变精子染色质凝聚（CC），并对其机制展开研究。在精子发生过程中，鱼精蛋白取代组蛋白，且在附睾成熟过程中形成的二硫键会使染色质凝聚。我们评估了小鼠睾丸和附睾中精子对铅的摄取情况以及对CC的影响（0.06% Pb²⁺/16周/饮用水）。获取来自附睾头（CP）和附睾尾 - 输精管（CE - VD）的精子，通过精子染色质结构分析（SCSA）测量CC。CP精子中的铅含量低于CE - VD精子中的铅含量，且与CC降低相关，而CE - VD精子中的铅与CC增加相关。观察到铅在细胞核内蓄积，且体外实验中铅与核巯基结合会减少染色质解凝聚。我们的结果表明，精子在睾丸发育和附睾运输过程中摄取铅并改变CC，这取决于铅掺入精子细胞核的时间，最终可能会干扰受精后染色质解凝聚过程。
