Purpose: The effects of the cryoprotectant and the container (holder) used for the vitrification of canine germinal vesicle stage oocytes were examined to improve the cryopreservation method for canine oocytes and embryos. Methods: Canine cumulus-oocyte complexes (COCs) were collected from ovaries, and were vitrified with E30S (30% ethylene glycol and 0.5 M sucrose) or DAP213 (2 M dimethyl sulfoxide, 1 M acetamide, and 3 M propylene glycol) solution held by a cryotube or cryotop sheets. After warming, the oocytes were stained with propidium iodide for the assessment of their plasma membrane integrity. Results: In all the vitrification groups, more than 65% of the vitrified oocytes displayed a normal morphology (E30S-top, 65.6%; DAP-tube, 67.3%; DAP-top, 80.0%). However, when assessed by propidium iodide staining, the viability of oocytes in the DAP-top group (43.6%) was higher than that in the E30S-top group (21.3%, P < 0.05). Furthermore, the viability of the oocytes in the DAP-top group (43.6%) was higher than that in the DAP-tube group (4.1%, P < 0.05). Conclusions: These results suggest that a combination of DAP213 as the cryoprotectant and a cryotop sheet as the holder improved viability after the vitrification of canine oocytes at the germinal vesicle stage.
Purpose: The effects of the cryoprotectant and the container (holder) used for the vitrification of canine germinal vesicle stage oocytes were examined to improve the cryopreservation method for canine oocytes and embryos. Methods:Canine cumulus-oocyte complexes (COCs) were collected from ovaries, and were vitrified with E30S (30% ethylene glycol and 0.5 M sucrose) or DAP213 (2 M dimethyl sulfoxide, 1 M acetamide, and 3 M propylene glycol) solution held by a cryotube or cryotop sheets. After warming, the oocytes were stained with propidium iodide for the assessment of their plasma membrane integrity. Results: In all the vitrification groups, more than 65% of the vitrified oocytes displayed a normal morphology (E30S-top, 65.6%; DAP-tube, 67.3%; DAP-top, 80.0%). However, when assessed by propidium iodide staining, the viability of oocytes in the DAP-top group (43.6%) was higher than that in the E30S-top group (21.3%, P < 0.05). Furthermore, the viability of the oocytes in the DAP-top group (43.6%) was higher than that in the DAP-tube group (4.1%, P < 0.05). Conclusions: These results suggest that a combination of DAP213 as the cryoprotectant and a cryotop sheet as the holder improved viability after the vitrification of canine oocytes at the germinal vesicle stage.
Authors: Rhiannon L Bolton; Andrew Mooney; Matt T Pettit; Anthony E Bolton; Lucy Morgan; Gabby J Drake; Ruth Appeltant; Susan L Walker; James D Gillis; Christina Hvilsom Journal: Reprod Fertil Date: 2022-06-30