Control of sperm concentration is necessary for standardization of sperm cryopreservation in aquatic species: Evidence from sperm agglutination in oysters
Control of sperm concentration is necessary for standardization of sperm cryopreservation in aquatic species: Evidence from sperm agglutination in oysters
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DOI：
10.1016/j.cryobiol.2006.11.007
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发表时间：
2007-02-01
期刊：
影响因子：
2.7
通讯作者：
Tiersch, Terrence R.
中科院分区：
文献类型：
--
作者：
Dong, Qiaoxiang;Huang, Changjiang;Tiersch, Terrence R.
水生生物精子冷冻保存缺乏标准化是各种研究不一致的主要原因之一。特别是，在程序优化过程中很少尝试标准化精子浓度。本研究旨在通过对太平洋巨牡蛎精子凝集的研究，引起人们对精子浓度标准化的关注。解冻后精子凝集是各种水生物种观察到的相对常见的现象，特别是在使用次优冷冻保存方案时；然而，尚未做出系统的尝试来解释这一现象。本研究评估了影响二倍体和四倍体太平洋牡蛎解冻样品精子凝集的各种因素，并且是第一份针对任何水生生物解冻样品精子凝集现象的详细报告。牡蛎精子的凝集被分为六个等级，等级范围从0（均匀悬浮）到5（发育良好的“面条”）。研究发现，解冻样品中的凝集主要是由于缺乏针对特定精子浓度的足够的冷冻保护剂。有趣的是，高水平的凝集并不一定导致受精率低。相反，一些精子细胞似乎在 0.5 毫升法国吸管内获得了保护，免受外周凝集的形成。精子凝集的确切机制仍不清楚。然而，面条横截面的形态学检查（凝集水平 5）表明至少有两种形式的凝集（有和没有冷冻保护剂形成），这可以用作了解吸管微环境内冷冻保存过程的工具。此外，除了冷冻保护剂的类型、冷冻保护剂浓度以及冷却和解冻方法之外，精子凝集水平直接由精子浓度决定，这一事实强调了程序标准化和涉及多因素的方案的系统优化和整合的重要性。 (c) 2006 Elsevier Inc. 保留所有权利。
A lack of standardization in sperm cryopreservation of aquatic organisms is one of the main reasons for inconsistency observed among various studies. In particular, there have been few attempts to standardize sperm concentration during procedural optimization. This study was intended to call attention to sperm concentration standardization through research of sperm agglutination in Pacific oysters Crassostrea gigas. Sperm agglutination after thawing is a relatively frequent phenomenon observed for various aquatic species, especially when sub-optimal cryopreservation protocols are used; however, no systematic attempts have been made to explain this phenomenon. The present study evaluated various factors affecting sperm agglutination of thawed samples from diploid and tetraploid Pacific oysters, and is the first detailed report addressing the sperm agglutination phenomenon of thawed samples from any aquatic organism. Agglutination of oyster sperm was classified into six levels with a scale ranging from 0 (homogenous suspension) to 5 (well-developed "noodles"). It was found that agglutination in thawed samples was mainly due to the lack of sufficient cryoprotectant for a specific sperm concentration. Interestingly, high levels of agglutination did not necessarily lead to low fertilization. On the contrary, some sperm cells appeared to gain protection from the formation of peripheral agglutination within 0.5-ml French straws. The exact mechanism of sperm agglutination remains unclear. However, morphological examination of cross sections of the noodles (agglutination level 5) indicated at least two forms of agglutination (formed with and without cryoprotectant) which could be used as a tool to understand the cryopreservation process within the micro-environment of the straw. Furthermore, the fact that the level of sperm agglutination was directly determined by sperm concentration, in addition to the type of cryoprotectant, cryoprotectant concentration, and cooling and thawing methods emphasized the importance of procedural standardization and systematic optimization and integration of protocols involving multiple factors. (c) 2006 Elsevier Inc. All rights reserved.