Cryoprotection synergism between glycerol and dimethyl sulfoxide improves the mitochondrial transmembrane potential, plasmalemma, acrosomal and DNA integrities, and in vivo fertility of water buffalo (Bubalus bubalis) spermatozoa.

The objective of the study was to devise a cryoprotection synergism between glycerol and dimethyl sulfoxide (DMSO) for water buffalo spermatozoa. Additionally, the effect of best evolved concentrations of glycerol and DMSO in extender was assessed on in vivo fertility of buffalo spermatozoa. Ejaculates (n = 30) were equally distributed into five aliquots; first aliquot was diluted at 37 °C in extender having 7 % glycerol (control); second aliquot was diluted at 37 °C as well as at 4 °C in extender having 3.5 % DMSO (Group 1); third aliquot was diluted at 37 °C in extender having 3.5 % glycerol and then at 4 °C in extender having 3.5 % DMSO (Group 2); fourth aliquot was diluted at 37 °C in extender having 3.5 % DMSO and then at 4 °C in extender having 3.5 % glycerol (Group 3); fifth aliquot was diluted in extenders having 1.75 % glycerol and 1.75 % DMSO at 37 as well as at 4 °C (Group 4). At post thawing, sperm progressive motility (%), rapid velocity (%), average path velocity (µm/s), curved line velocity (µm/s), in vitro longevity (%), structural and functional integrity of plasmalemma (%), mitochondrial transmembrane potential (%) and viable sperm with intact acrosome (%) were higher (P < 0.05) in Group 4 compared to other treatment groups and control. Regarding sperm DNA integrity (%); it was higher (P < 0.05) in Group 4 compared to Group 1, 3 and control. The in vivo fertility (%) of buffalo spermatozoa was significantly higher with Group 4 compared to control (69.45 vs. 59.81). In conclusion, synergism exists between glycerol and DMSO (Group 4) in improving the quality and in vivo fertility of cryopreserved water buffalo spermatozoa.