Morphological survival and subsequent in vitro maturation of denuded and cumulus compact Bubaline oocytes cryopreserved by ultra rapid cooling

Abstract

Culturable grade oocytes (n=380) recovered by aspiration of surface follicles from buffalo ovaries (n=97) were either mechanically denuded (DN) or kept cumulus compact (CC) and were vitrified in Dulbecco's phosphate buffered saline + 0.4% sucrose, 0.4% bovine serum albumin and 6 M concentrations of either ethylene glycol (EG) or propylene glycol (PG). Oocytes were randomly allocated to four groups of vitrification (EGCC, EGDN, PGCC and PGDN) and cryostorage for 7-10 days in liquid nitrogen. They were then warmed to record morphological survival and morphologically normal oocytes were matured in vitro along with fresh oocytes (control) for 24 h in TCM-199 containing hormones (LH + FSH + estradiol) at 38.5 0 C and 5% CO2 in humidified air in a CO2 incubator. The arcsine transformed data of the proportion of morphologic survival of oocytes and in vitro maturation of oocytes was compared by DNMRtest. The morphologically normal oocytes were significantly higher (P<0.05) for cumulus compact oocytes compared with denuded oocytes for both cryoprotectants EG and PG. The in vitro maturation was significantly higher (P<0.05) for nonvitrified oocytes (control) compared to vitrified oocytes. Significantly higher (P<0.05) proportion of cumulus compact oocytes matured in vitro compared to denuded oocytes for both cryoprotectants EG and PG. The differences between the cryoprotectants were non-significant. It was concluded that cryo-damage to the oocytes during vitrification can be minimized by the presence of cumulus cells with the oocyte, whereas the two cryoprotectants EG and PG are equally effective in preventing cryodamage to oocytes.

Survivability of caprine oocytes vitrified in conventional and open pulled straws

“…The postvitrification abnormalities observed in the present study are in close correlation with the earlier (30). The major cryoinjuries were associated with CS vitrification (Table 2), which may explain the low survivability of COCs vitrified by the CS method as compared to the OPS method in the present study.…”

Effect of antioxidant on in-vitro maturation of vitrified bovine oocytes

“…The actin filaments, junctures between cumulus cells and zonapellucida, become disorganized leading to alterations in the secondary structure of the zonapellucida proteins as well as the carbohydrate residues (Bogliolo et al 2012). The mixture of cryoprotectants used in the present study might have reduced its individual toxicity as well as probable major alterations in ultra-structure of bovine oocytes (Cocchia et al 2010, Purohit et al 2012, Dutta et al 2013.…”

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

“…EG is an important cryoprotectant due to its higher penetrating ability with low toxicity [12]. EG and PG are equally effective in preventing cryodamage of buffalo oocytes [13]. Disaccharides are recently being used for the vitrification of oocytes in various species, including mouse [14], cattle [15], buffalo [16], and human [17,18].…”