NEW CRYOPROTECTANS SUITABLE FOR SLOW FREEZING PROCESS OF EPIDIDYMAL SPERMATOZOA OF ALPACA (Lama pacos)
Nadia Canorio, Fernando Paredes, Martha Valdivia
Cryopreservation of sperm is a technique of assisted reproduction that cause changes and damage to mitochondria, acrosome and tail of sperm, for that reason, a suitable methodology of freezing is necessary. The objective of this study was to use new cryoprotectans suitable for freezing epididymal spermatozoa of Alpaca (Lama pacos) in a slow freezing method. The epididymides of alpaca were transported from Huancavelica city to our laboratory at 4șC in physiological solution. The sperm cells were extracted from the epididymis fourteen hours later in HAMF10 medium. The YolK-Citrate medium with the cryoprotectants: Dimethyl sulfoxide (0,5M, 0,25M, 0,125M) and Dimethylacetamide (0,75M, 0,385M, 0,18M) were used for the cryopreservation, and were compared with a control group cryopreserved with Glycerol (0.6M). The stabilization period was one hour to 4șC. The slow freezing was done with the use of a programmable biofreezer with the Cryogenesis 4.1 computer software until the temperature reached -80°C and finally the samples were transferred to liquid nitrogen to -196șC. After the thawing process the differences between the results of viability and membrane integrity were significant; in the case of motility we found two groups: one group consisting by Me2SO4 0.25M, Me2SO4 0.5M, DMA 0.375M and DMA 0.75M in this group the highest motility values were obtained; and the second group consisted by Me2SO4 0.5M, 0.18M DMA and Glycerol 0.6M where values were the lowest. Cryoprotective agents DMA (0.375M and 0.75M) and Me2SO4 (0.25M and 0.5M) had an effective cryoprotectant effect compared to the control sample (Glycerol 0.6M).