Codrington A M, Hales B F, Robaire B
Department of Pharmacology, McGill University, Montreal, Quebec, Canada.
Hum Reprod. 2007 May;22(5):1431-42. doi: 10.1093/humrep/dem002. Epub 2007 Feb 15.
The formation of mature sperm involves the expression of numerous proteins during spermiogenesis and the replacement of histones with protamines to package the genome. Exposure to cyclophosphamide (CPA), an anticancer alkylating agent, during spermiogenesis may disrupt chromatin condensation with adverse consequences to the offspring.
Adult male rats were given CPA in one of two schedules: (i) subchronic, 4 days - day 1 (100 mg kg(-1)) and days 2-4 (50 mg kg(-1) per day) or (ii) chronic - daily (6.0 mg kg(-1) per day). Animals were euthanized on days 14, 21 or 28.
The effects of CPA on epididymal sperm chromatin structure were germ-cell-phase specific; mid-spermiogenic spermatids were most sensitive. The acridine orange DNA denaturation assay showed significant increases in susceptibility to denaturation (P < 0.01). Chromatin packaging assessment revealed 1,4-dithiothreitol-dependent chromomycin A3 DNA binding and less condensed, protamine-deficient sperm; the total thiol (P < 0.001) and protamine contents (P < 0.01), measured using monobromobimane and the HUP1N protamine 1 antibody, respectively, were reduced. The sperm basic proteome was also altered; proteins that were identified are involved in events during spermiogenesis and fertilization.
Paternal exposure to CPA alters sperm chromatin structure, as well as the composition of sperm head basic proteins. We speculate that these changes underlie effects on fertilization and embryo development.
成熟精子的形成涉及精子发生过程中多种蛋白质的表达以及组蛋白被鱼精蛋白取代以包装基因组。在精子发生过程中接触环磷酰胺（CPA），一种抗癌烷化剂，可能会破坏染色质凝聚，对后代产生不良影响。
成年雄性大鼠按以下两种方案之一给予CPA：（i）亚慢性，第1天（100 mg kg⁻¹），第2 - 4天（每天50 mg kg⁻¹）；或（ii）慢性 - 每天（每天6.0 mg kg⁻¹）。在第14、21或28天对动物实施安乐死。
CPA对附睾精子染色质结构的影响具有生殖细胞阶段特异性；精子发生中期的精子细胞最敏感。吖啶橙DNA变性试验显示变性敏感性显著增加（P < 0.01）。染色质包装评估显示，1,4 - 二硫苏糖醇依赖性放线菌素A3 DNA结合以及凝聚程度较低、鱼精蛋白缺乏的精子；分别使用单溴双马来酰胺和HUP1N鱼精蛋白1抗体测量的总巯基（P < 0.001）和鱼精蛋白含量（P < 0.01）降低。精子碱性蛋白质组也发生了改变；鉴定出的蛋白质参与精子发生和受精过程中的事件。
父本接触CPA会改变精子染色质结构以及精子头部碱性蛋白质的组成。我们推测这些变化是对受精和胚胎发育产生影响的基础。
