Animal Biochemistry Division, National Dairy Research Institute, Karnal 132001, Haryana, India.
Mol Biol Rep. 2011 Mar;38(3):1499-506. doi: 10.1007/s11033-010-0257-1. Epub 2010 Sep 19.
Use of cryopreserved semen has become an important tool in assisted reproduction but freezing and thawing cause sub-lethal damage to spermatozoa. This is detrimental to sperm because of the membrane damage including permeability and integrity. An excess generation of reactive oxygen species (ROS) creates oxidative stress due to reduced antioxidant status of the cryopreserved spermatozoa. In the present study fresh buffalo semen was collected and divided into two aliquots. One aliquot was used for fresh semen analysis and the other was cryopreserved in Tris-egg yolk-citrate extender. The semen samples were used to study different sperm quality parameters like motility, viability, membrane integrity and total antioxidant status. The DNA integrity in fresh and cryopreserved spermatozoa was also studied using comet assay. The sperm quality parameters like post-thaw sperm motility, viability, membrane integrity and total antioxidant status of cryopreserved spermatozoa were significantly lowered (P < 0.05) compared to fresh spermatozoa. The DNA fragmentation in cryopreserved spermatozoa was significantly higher (P < 0.01) as compared to fresh spermatozoa. The results show that the irreversible DNA damage occurs in spermatozoa during cryopreservation.
冷冻保存的精液在辅助生殖中已成为一种重要的工具，但冷冻和解冻会对精子造成亚致死损伤。这对精子是有害的，因为膜的损伤包括通透性和完整性。由于冷冻保存的精子抗氧化状态降低，过量产生的活性氧（ROS）会导致氧化应激。在本研究中，采集新鲜水牛精液并分为两份。一份用于新鲜精液分析，另一份用 Tris-卵黄-柠檬酸盐稀释液冷冻保存。使用这些精液样本研究了不同的精子质量参数，如活力、存活率、膜完整性和总抗氧化状态。还使用彗星试验研究了新鲜和冷冻保存的精子的 DNA 完整性。与新鲜精子相比，冷冻保存的精子解冻后活力、存活率、膜完整性和总抗氧化状态等精子质量参数显著降低（P<0.05）。冷冻保存的精子的 DNA 碎片化明显更高（P<0.01）。结果表明，在冷冻保存过程中，精子会发生不可逆的 DNA 损伤。
