Strip pulled straw: cost effective alternative cryodevice for the vitrification of oocytes

Increased cooling and warming rates by using a suitable cryodevice allows the use of lower cryoprotectant concentration and reduces cryoinjuries as a result of the rapid passage through the 'dangerous' temperature zone.

To evaluate the effectiveness of newly customized strip pulled straw (SPS) with respect to post warming quality, viability, and in vitro maturation for immature oocytes post-vitrification of.

SPS was prepared using conventional French mini straw to combine the merits of OPS and the Cryotop system. Immature sheep oocytes were treated in 15% EG + 15% DMSO, loaded on SPS and plunged into liquid nitrogen (LN). Post thaw quality, viability, and maturation rates of oocytes were determined after 1 week storage in LN.

SPS achieved a post-thaw morphological survival of 90.9% with 9.0% morphological defects, 96.4% viability and 51% in vitro maturation. In comparison to OPS, SPS had higher post thaw survival (86.5% vs 67.9%) and maturation rate (57.7% vs 50.5%) with lower morphological defects (13.5% vs 32.1%). Cumulus cell loss was the highest among morphological abnormalities of post warm oocytes in SPS (40.9%) and OPS (44.1%). The data showed acceptable post thaw survival, viability and in vitro maturation rate of immature ovine oocytes using SPS as compared to traditional OPS.

SPS can be used as a cost effective alternative device for oocyte vitrification. Doi: 10.54680/fr23410110212.