Types of damages on buffalo oocytes after vitrification with different concentration of ethylene glycol and dimethyl sulphoxide

Abstract

The objective of the present study is to observe the oocytes damages after vitrification in combination of ethylene glycol (EG) and dimethyl sulphoxide (DMSO) at different concentration with 1 and 3 min equilibration time (ET). A total 826 cumulus oocytes complexes were obtained by follicular aspiration from 278 ovaries of buffaloes slaughtered at local abattoir. The compact oocyte complexes (COCs) with evenly granulated ooplasm were vitrified using 4 different concentrations, viz. 10, 15, 20, 25% of EG and DMSO with 1 and 3 min of ET. After 7 days of cryopreservation, the vitrified oocytes were thawed and these oocytes were evaluated for morphologically normal recovery, partial cumulus loss and different damages. The normal recovery was observed higher in 25% of EG and DMSO (3 min ET) 62.61%, partial cumulus loss found higher in 25% EG and DMSO (3 min ET) 11.86% and damaged oocyte was observed in 15% EG and DMSO (1 min ET) 43.61%. Among all damages, the cracked zona was prevalent and observed significantly higher in 10% EG and DMSO (1 min ET) 93.7%, shrinkage\ change in shape were higher in 15% EG and DMSO (1 min ET) 22.2% and split in 2 halves were observed in 15% EG and DMSO (1 min ET) 15.6%. The damaged per cent in 10% EG and DMSO (1 and 3 min ET) was significantly higher than other concentrations. However, better results were obtained in 25% concentration compared to other concentrations of EG and DMSO.