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Published on: December 12, 2011
Cryopreservation of Cynomolgus Macaque (Macaca fascicularis) Sperm by Using a Commercial Egg-YolkFree Freezing Medium
Yaping Yan1, Lei Ao2, Hong Wang1
1Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, National Engineering Research Center of Biomedicine and Animal Science, Kunming, Yunnan, China.
Abstract:
Conventional TRISegg yolk (TEY) freezing medium for the cryopreservation of NHP sperm has the risk of contamination due to widespread zoonotic diseases. This study was aimed at determining the optimal glycerol concentration, freezing rate, and holding time in liquid N2 vapor for the cryopreservation of cynomolgus macaque sperm by using a commercial egg-yolkfree freezing medium (SC medium) designed for human sperm cryopreservation. Sperm motility and acrosomal integrity after freezing were assessed. Sperm in SC medium (dilution ratio, 3:1) frozen at cooling rates of 67 and 183C/min in liquid N2 vapor showed higher post-thaw motility than did samples frozen at 435C/min. At the cooling rate of 183C/min and dilution in SC medium at a 3:1 ratio, post-thaw motility was higher after a holding time of 10 min than after 30 min (recommended by the manufacturer). In addition, post-thaw motility of sperm frozen in SC medium was higher with dilution ratios of 3:1, 4.5:1, and 6:1 compared with 9:1, 10.5:1, and 12:1, and the sample diluted 12:1 showed the lowest percentage of thawed sperm with intact acrosomes. Sperm showed higher post-thaw motility after freezing in TEY than in SC medium; acrosomal integrity did not differ between the 2 media. Our results indicated that cynomolgus macaque sperm can be cryopreserved successfully by using a commercial egg-yolkfree freezing medium, which provides an option for genetic preservation with decreased zoonotic risk in this important NHP species.
Insights
Cryopreservation of cynomolgus macaque sperm using an egg-yolk-free medium (SC medium) reduces zoonotic risk. Optimal freezing involves specific cooling rates and dilution ratios for successful sperm preservation.
Area of Science:
- Veterinary Science
- Reproductive Biology
- Cryobiology
Background:
- Conventional TRIS-egg yolk (TEY) medium for non-human primate (NHP) sperm cryopreservation poses zoonotic disease risks.
- Developing safer cryopreservation methods is crucial for NHP genetic preservation.
Purpose of the Study:
- To optimize cryopreservation of cynomolgus macaque sperm using a commercial egg-yolk-free medium (SC medium).
- To evaluate the impact of glycerol concentration, cooling rate, and holding time on post-thaw sperm viability.
Main Methods:
- Cynomolgus macaque sperm were cryopreserved in SC medium under various conditions.
- Post-thaw sperm motility and acrosomal integrity were assessed.
- Different cooling rates (67, 183, 435°C/min), holding times (10, 30 min), and dilution ratios (3:1 to 12:1) were tested.
Main Results:
- Cooling rates of 67 and 183°C/min yielded higher post-thaw motility than 435°C/min.
- A 10-minute holding time was superior to 30 minutes at 183°C/min.
- Dilution ratios of 3:1 to 6:1 resulted in better motility and acrosomal integrity compared to higher ratios.
Conclusions:
- Cynomolgus macaque sperm can be successfully cryopreserved using SC medium, an egg-yolk-free alternative.
- This method offers a reduced zoonotic risk for NHP genetic preservation.
- Optimized parameters include specific cooling rates and dilution ratios for improved cryosurvival.
