Zhileng xuebao (Jan 2017)
Osmotic Injury to Porcine Oocytes during Cryoprotective Agents Addition and Removal Processes
Abstract
Oocyte cryopreservation has become a practical tool in assisted reproductive technology and fertility preservation. Cryoprotective agents (CPAs) addition and removal are essential steps during oocytes cryopreservation, however, the processes of CPAs addition and removal may cause fatal osmotic and toxic injuries to oocytes. In order to study the injuries of porcine MII-stage oocytes during CPAs addition and removal combined processes and minimize osmotic and toxic injuries to oocytes, primarily, a microfluidic device for continuous loading and unloading of CPAs was designed and fabricated in this study. CPAs were loaded and unloaded with the microfluidic linear method and the conventional step-wise method, respectively. Then, the cell volume changes and the effects on the survival rate and developmental potential of oocytes were investigated. The results showed that the oocyte volume changes with the microfluidic device were obviously less than step-wise method. The survival, cleavage and blastocyst rate of oocytes were 95.3%, 64.4%, and 19.4%, respectively, which were significantly higher than the traditional step-wise method (79.4%, 43.6%, and 9.7%) (P<0.05). In conclusion, microfluidic device can be used efficiently to load and unload of CPAs, and significantly reduce the osmotic shock to oocytes, which may open up a new path for oocyte cryopreservation.
