Differences among dogs in response of their spermatozoa to cryopreservation using various cooling and warming rates
详细信息 查看全文
- 作者：Yu ; I. ; Songsasen ; N. ; Godke ; R.A. ; Leibo ; S.P.
- 关键词：Spermatozoa ; Canine ; Cooling rates ; Warming rates
- 刊名：Cryobiology
- 出版年：2002
- 出版时间：February, 2002
- 年：2002
- 卷：44
- 期：1
- 页码：62-78
- 全文大小：219 K
文摘
Spermatozoa collected from the caudae epididymides of 16 dogs of various breeds were suspended in an isotonic salt solution (DIMI medium) containing 0.6 M glycerol, frozen in liquid nitrogen, and their “survival” was measured after thawing. In the first experimental series, duplicate samples of spermatozoa from each of 11 dogs were cooled at rates of 0.5, 3, 11, 58, or 209 °C/min, stored in liquid nitrogen, and the frozen samples warmed at 
830 or at 33 °C/min. Sperm “survival” was judged by microscopic assessments of motility and of membrane integrity, the latter as assayed with Fertilight, a double fluorescent stain. Motility of frozen spermatozoa that were thawed rapidly, averaged for 11 dogs, was low at low rates, increased to a maximum at 11 °C/min, and then decreased significantly at higher rates (P<0.01). This inverted V-shaped curve was also observed with slow thawing, although the apparent optimum cooling rate ranged from 3 to 11 °C/min. The integrity of sperm plasma membranes showed a similar dependence on cooling rate, although the percentages of spermatozoa with intact plasma membranes were higher than the percentages of motile spermatozoa. Motility of spermatozoa, as a function of cooling rate, varied considerably from male to male (P<0.01), whereas membrane integrity was much more consistent among the 11 dogs. In the second experimental series with spermatozoa from 5 dogs, motility of spermatozoa frozen at 0.5 °C/min and warmed at 3.6, 33, 140, or 830 °C/min also exhibited an inverted V-shaped survival curve, in this case as a function of warming rate. In summary, high survival of frozen–thawed canine epididymal spermatozoa depended on both cooling and warming rates, but spermatozoa from each dog exhibited their own sensitivity to cooling and warming rates.
830 or at 33 °C/min. Sperm “survival” was judged by microscopic assessments of motility and of membrane integrity, the latter as assayed with Fertilight, a double fluorescent stain. Motility of frozen spermatozoa that were thawed rapidly, averaged for 11 dogs, was low at low rates, increased to a maximum at 11 °C/min, and then decreased significantly at higher rates (P<0.01). This inverted V-shaped curve was also observed with slow thawing, although the apparent optimum cooling rate ranged from 3 to 11 °C/min. The integrity of sperm plasma membranes showed a similar dependence on cooling rate, although the percentages of spermatozoa with intact plasma membranes were higher than the percentages of motile spermatozoa. Motility of spermatozoa, as a function of cooling rate, varied considerably from male to male (P<0.01), whereas membrane integrity was much more consistent among the 11 dogs. In the second experimental series with spermatozoa from 5 dogs, motility of spermatozoa frozen at 0.5 °C/min and warmed at 3.6, 33, 140, or 830 °C/min also exhibited an inverted V-shaped survival curve, in this case as a function of warming rate. In summary, high survival of frozen–thawed canine epididymal spermatozoa depended on both cooling and warming rates, but spermatozoa from each dog exhibited their own sensitivity to cooling and warming rates.