精子DNA损伤对无主要附属性腺金仓鼠的受精卵和双细胞胚胎中RAD51和p53蛋白水平的影响

Department of Anatomy, Histology and Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China

We previously reported that the male accessory sex gland (ASG) secretion is the main source of antioxidants to safeguard sperm genomic integrity and functional competence. Removal of all ASGs in the golden hamster can reduce male fertility by increasing embryo wastage. This study aims to investigate whether the oxidative DNA-damaged sperm from hamsters without all ASGs (TX) could successfully fertilize oocytes and to qualify the status of DNA repair by the expression of RAD51 and p53 proteins. Here we demonstrated a significantly higher DNA-base adduct formation (8-hydroxy-2′-deoxyguanosine) in sperm from TX males than those from sham-operated males. Comet assays demonstrated that all female pronuclei in both zygotes were intact, but single- and double-strand DNA damage was found in decondensed sperm in TX males only. DNA damage could also be detected in both nuclei of the TX 2-cell embryos. RAD51, a DNA repair enzyme, was found to be evenly distributed in the cytoplasm and nuclei in oocytes/zygotes, while at the 2-cell stage, a strong expression of p53 protein and a larger clear perinuclear area without RAD51 expression were found in TX embryos. In conclusion, we demonstrated for the first time DNA damage in decondensed sperm of zygotes and blastomeres of 2-cell stage embryos sired by TX males, resulting in the activation of DNA repair. Sperm DNA damage could induce the increase in p53 expression and the reduction of RAD51 expression in the TX 2-cell stage embryos. © 2012 Elsevier Inc. All rights reserved.

Chen, H.; Department of Anatomy, Histology and Embryology, Shanghai Medical College, Fudan University, Shanghai 200032, China; email:hchen@graduate.hku.hk