This study is summarised as evidence for the following.

Action Category

Freeze sperm or eggs for future use

Action Link
Amphibian Conservation
  1. Freeze sperm or eggs for future use

    A replicated, controlled study in 1997 of captive wood frogs Rana sylvatica in the USA (Mugnano et al. 1998) found that some sperm recovered following freezing for up to 58 weeks provided that the cryoprotectant dimethyl sulfoxide or glycerol was used. Sperm viability was significantly reduced after freezing compared to chilling for 1–30 hours with glycerol (13–17 vs 50–55%) or dimethyl sulfoxide (10–13 vs 60%). However, viability was zero without a cryoprotectant. Viability was not significantly affected by cryoprotectant concentration. There was no significant difference in viability following freezing for 1–30 hours compared to 58 weeks. Whole testes frozen in dimethyl sulfoxide had significantly higher sperm viability than those in glycerol (14 vs 5%). When chilled, sperm in had lower survival than controls and so glucose was excluded. Testes from five wild-caught frogs were macerated in a buffer. Sperm solutions from each were mixed with glucose (2 M), glycerol or dimethyl sulfoxide (1.5 or 3 M), chilled for 20 minutes and then half were frozen to -80°C in ethanol/dry ice (rate 130°C/minute) for 1–30 hours or 58 weeks. Thawing was in a 30°C water bath. Four intact testes were frozen at −80°C in glucose or dimethyl sulfoxide for five days.


Output references

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