Gillis Amanda B, Guy Emmet L, Kouba Andrew J, Allen Peter J, Marcec-Greaves Ruth M, Kouba Carrie K
Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, MS, United States of America.
Department of Wildlife, Fisheries, and Aquaculture, Mississippi State University, Mississippi State, MS, United States of America.
PLoS One. 2021 Jan 11;16(1):e0245047. doi: 10.1371/journal.pone.0245047. eCollection 2021.
The aims of this project were to characterize tiger salamander (Ambystoma tigrinum) spermatozoa motility over time, when excreted as either milt or spermic urine prior to packaging into a spermatophore, and to determine the effect of temperature on sperm motility. A split-plot design was utilized to assess the motility of the two pre-spermatophore sample types at two temperatures, 0°C and 20°C (n = 10 for each treatment). Spermiation was induced through exogenous hormone treatment of luteinizing hormone releasing hormone analog in order to collect both milt and spermic urine, which were evaluated for motility, divided into two separate aliquots, and subsequently stored in either an ice-bath (0°C) or on the benchtop (20°C). The decay rate of sperm motility was assessed by reevaluating subsamples at 0.5, 1, 2, 3, 5, 7, and 24 hours following the initial assessment. Results showed that sperm stored at 0°C had significantly higher progressive, non-progressive, and total motility for both sperm collection types over time. An interaction was found between collection type and time, with milt exhibiting lower initial motility that was more sustainable over time, compared to spermic urine. For both milt and spermic urine, motility decreased rapidly with storage duration, indicating samples should be used as soon as possible to maximize motility for in-vitro fertilization and cryopreservation. This is the first study to describe the differences in sperm motility between milt and spermic urine from an internally fertilizing caudate and demonstrates the benefits of near freezing temperatures on sperm longevity.
本项目的目的是表征虎纹钝口螈（Ambystoma tigrinum）精子在排出后随时间的运动情况，排出的精子以精液或精尿形式存在，之后被包裹成精荚，同时确定温度对精子运动的影响。采用裂区设计来评估两种精荚前样本类型在0°C和20°C这两个温度下的运动情况（每种处理n = 10）。通过对促黄体生成素释放激素类似物进行外源激素处理诱导排精，以收集精液和精尿，对其运动情况进行评估，分成两个单独的等分试样，随后分别储存在冰浴（0°C）或台面上（20°C）。在初始评估后的0.5、1、2、3、5、7和24小时对子样本进行重新评估，以评估精子运动的衰减率。结果表明，对于两种精子收集类型，在0°C储存的精子随时间推移具有显著更高的前进运动、非前进运动和总运动能力。发现收集类型和时间之间存在相互作用，与精尿相比，精液的初始运动能力较低，但随时间更具可持续性。对于精液和精尿，运动能力均随储存时间迅速下降，这表明样本应尽快使用，以最大限度地提高体外受精和冷冻保存的运动能力。这是第一项描述体内受精有尾目动物精液和精尿之间精子运动差异的研究，并证明了接近冰点温度对精子寿命的益处。
