Effect of type of cryoprotectant on morphology and developmental competence of in vitro-matured buffalo (Bubalus bubalis) oocytes subjected to slow freezing or vitrification

Abstract

The present study examined the effects of different cryoprotectants on morphology and developmental competence of in vitro-matured buffalo oocytes after slow freezing or vitrification. After slow freezing in dimethyl sulfoxide (DMSO), ethylene glycol (EG) or 1,2-propanediol (PROH), at 1.0 or 1.5 m each, the proportion of morphologically normal oocytes recovered was significantly higher (P < 0.05) with 1.5 than 1.0 m for all cryoprotectants and was highest (P < 0.05) for 1.5 m DMSO. Following vitrification, the percentage of morphologically normal oocytes recovered was lower (P < 0.01) for 40% EG than for 40% DMSO, 20% EG + 20% DMSO or 20% EG + 20% PROH. The most common damage, irrespective of the cryopreservation method, was loss of cumulus mass. The cleavage rate and the proportion of vitrified-warmed oocytes that developed to morulae/blastocysts were significantly higher (P < 0.01) for 20% EG + 20% DMSO than for the other groups. A higher proportion of oocytes developed to morulae (11.5% v. 4.3%) or blastocysts (5.4% v. 0.6%) after vitrification in 20% EG + 20% DMSO than after slow freezing in 1.5 m DMSO. In conclusion, vitrification was more effective than slow freezing for the cryopreservation of in vitro-matured buffalo oocytes.

Effects of cryoprotectants and cryoprotectant combinations on viability and maturation rates of Camelus dromedarius oocytes vitrified at germinal vesicle stage

“…This may be due to its slow permeability or penetration into the cell (Mukaida et al, ), and it causes disassembly of the spindle microtubules and movement of the pericentriolar material to the centre of oocytes (Trounson & Kirby, ). However, DMSO was more effective than EG or PROH for the slow freezing of immature buffalo oocytes (Gautam et al, ). Also during cryopreservation of ovarian tissues, the extent of follicular survival is at least in part determined by the speed of cryoprotectant permeation.…”

“…Cryopreservation of oocytes collected from slaughtered animals of high genetic value and their subsequent application for production of transferable embryos may provide a chance to overcome the valuable germplasm lost and enable the genetic improvement of the species (Wani, Misra, & Maurya, ). Cryopreservations of germplasm were performed either by slow freezing (Gautam, Verma, Palta, Chauhan, & Manik, ) or vitrification (Yamada et al, ). The conventional slow freezing method for cryopreservation of oocytes and embryos often causes osmotic shock and intracellular ice crystallization resulting in cell damage (Ledda et al, ).…”

Reproductive biotechniques in buffaloes (Bubalus bubalis): status, prospects and challenges

“…The major problem with buffalo oocyte cryopreservation is low survival and/or poor developmental competence. Recent reports have highlighted improvements in the cryopreservation of both OPU-and abattoir-derived oocytes, with morulae and blastocysts obtained following IVF of oocytes cryopreserved using slow-freezing or vitrification, although the embryo production efficiency was lower than that for fresh oocytes (Gautam et al 2008a(Gautam et al , 2008b.…”

Effect of vitrification procedures on the subsequent development of in vitro matured swamp buffalo oocytes following in vitro fertilization

“…One essential factor for the cryosurvival of oocytes is the permeation of an optimum amount of CPAs into the oocytes that increases with the duration of exposure (Shaw, Bernard, Fuller, Hunter, & Shaw, ). The solution of 20% ethylene glycol (EG) + 20% dimethyl sulfoxide (DMSO) + 0.5 mol/L sucrose is one of the most effective CPAs for the cryopreservation of in vitro matured (IVM) buffalo oocytes (Gautam, Verma, Palta, Chauhan, & Manik, ; Liang, Phermthai, Nagai, Somfai, & Parnpai, ; Liang et al., 2012a; Mahmoud, Scholkamy, Ahmed, Seidel, & Nawito, ). A vitrification protocol using a solution of 35% EG + 5% polyvinylpyrrolidone (PVP) + 0.3 mol/L trehalose has been also shown to be effective for vitrifying cattle (Sripunya et al., ), porcine (Somfai et al., ), and buffalo oocytes (Liang et al., 2012a).…”