Yang H, Tiersch T R
Aquaculture Research Station, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA.
Theriogenology. 2009 Aug;72(3):386-92. doi: 10.1016/j.theriogenology.2009.03.007. Epub 2009 May 21.
The medaka, Oryzias latipes, is a well-recognized fish model for biomedical research. An understanding of gamete characteristics is necessary for experimental manipulations such as artificial fertilization and sperm cryopreservation. The goal of this study was to investigate sperm characteristics of motility initiation, duration, and retention in medaka. First, motility was initiated by osmolality values ranging from 25 to 686mOsm/kg, which included deionized water and hypotonic, isotonic, and hypertonic Hanks' balanced salt solution. The percentage of motile sperm was >80% when osmolality was <315mOsm/kg and decreased as osmolality increased. This is different from most fish with external fertilization in which sperm motility can be initiated by hypotonic (for freshwater fish) or hypertonic (for marine fish) solutions or by altering the concentration of specific ions such as potassium (e.g., in salmonids). Second, upon activation, the sperm remained continuously motile, with reserve capacity, for as long as 1 wk during storage at 4 degrees C. This was also different from other externally fertilizing fish, in which motility is typically maintained for seconds to several minutes. Third, after changing the osmolality to 46 to 68 mOsm/kg by adding deionized water, the motility of sperm held at 274 to 500 mOsm/kg was higher than the original motility (P</=0.035) after 24, 48, and 72h of storage at 4 degrees C. Fourth, the addition of glucose had no effect on maintaining sperm motility during refrigerated storage. To our knowledge, this combination of sperm motility characteristics is reported for the first time in fish and may be unique to medaka or may represent an undescribed modality of sperm behavior within euryhaline fish.
青鳉（Oryzias latipes）是一种广为人知的用于生物医学研究的鱼类模型。了解配子特征对于人工受精和精子冷冻保存等实验操作至关重要。本研究的目的是调查青鳉精子的活力启动、持续时间和保持能力等特征。首先，通过25至686mOsm/kg的渗透压值启动精子活力，这些渗透压值包括去离子水以及低渗、等渗和高渗的汉克斯平衡盐溶液。当渗透压<315mOsm/kg时，活动精子的百分比>80%，且随着渗透压升高而降低。这与大多数体外受精鱼类不同，在这些鱼类中，精子活力可由低渗溶液（对于淡水鱼）或高渗溶液（对于海水鱼）启动，或者通过改变特定离子（如钾）的浓度来启动（例如在鲑科鱼类中）。其次，精子激活后，在4℃储存期间，精子能够持续游动并具有储备能力，长达1周。这也与其他体外受精鱼类不同，在其他鱼类中，精子活力通常维持几秒到几分钟。第三，通过添加去离子水将渗透压改变为46至68mOsm/kg后，在4℃储存24、48和72小时后，渗透压保持在274至500mOsm/kg的精子活力高于原始活力（P≤0.035）。第四，添加葡萄糖对冷藏储存期间维持精子活力没有影响。据我们所知，这种精子活力特征的组合在鱼类中首次报道，可能是青鳉所特有的，或者可能代表广盐性鱼类中一种未被描述的精子行为模式。
