Effect of Polyvinylpyrrolidone on Vitrification of Buffalo (Bubalus bubalis) Oocytes

Abstract

Vitrification, a method of rapid cooling, is an alternate cryopreservation method of oocytes and embryos. The present study was aimed to examine the effect of polyvinylpyrrolidone (PVP) on vitrification of buffalo oocytes. Cumulus oocyte complexes (COCs) with fully grown oocytes (120-130 µm in diameter) were aspirated from slaughtered buffalo ovaries for vitrification. COCs were treated with equilibration solution at room temperature for 5 min and then transferred to a vitrification solution for 1 min. Then the COCs were submerged into liquid nitrogen (-196C) for a while using cryotops. The COCs were thawed, diluted, and washed in a washing solution for 5 min, respectively. Vitrified oocytes were incubated for in vitro maturation (IVM) at 38.5C under an atmosphere of 5% CO2 in the air for 24 hrs. Cumulus cells surrounding the oocytes were removed mechanically, oocytes were fixed in acetic acid and ethanol, and stained with aceto-orcein to examine the meiotic stages of oocytes. The numbers of morphologically normal oocytes after vitrification were higher in 5% PVP than 0 and 10% PVP groups. A proportion of oocytes treated with 5% PVP reached the metaphase II (MII) stage while none of the oocytes from 0% and 10% PVP groupsdeveloped beyond anaphase I and metaphase I (MI) stages, respectively. These results show that PVP can be used as a cryoprotectant for the vitrification of buffalo oocytes.

Current status of assisted reproductive technologies in buffaloes

“…While DMSO has been used for the vitrification of oocytes in buffalo (Wani, Maurya, et al, 2004), it has been reported however that DMSO adversely affects the developmental processes of oocytes (Vincent et al, 1990). Most recently, the replacement of DMSO with 5% PVP on EG + sucrose vitrification solution protects buffalo oocytes from cryoinjury and supports the meiotic progression of oocytes in‐vitro after vitrification and warming (Jannatul et al, 2020).…”

Enhanced Cellular Cryopreservation by Biopolymer-Associated Suppression of RhoA/ROCK Signaling Pathway

“…Alternatively, synthetic polymers such as polyvinyl alcohol (PVA) have the advantage of being able to mimic the function of AFPs by designing them to inhibit the formation of ice crystals and the advantage of being produced cheaply in large quantities [ 25 ]. Although synthetic, non-biodegradable polymer-based cryoprotectants were effective in reducing the size of ice crystals, their residues could potentially lead to less biocompatibility in vivo environments [ 26 ]. Recently, biodegradable polymeric cryoprotectants have gained special interest as cryoprotectants due to their complete enzymatic degradation in vivo and excellent biocompatibility [ 5 , 11 , 27 , 28 , 29 ].…”