6th World Congress on Biotechnology
New Delhi, India
National Institute of Animal Nutrition and Physiology, Bangalore
Title: Selection of developmentally competent ovine oocytes by Brilliant Cresyl Blue (BCB) staining improves blastocyst development rate
Biography: Sukanta Mondal
The brilliant cresyl blue (BCB) staining evaluates the activity of glucose-6-phosphate dehydrogenase (G6PDH); the activity of this enzyme is greatest in growing oocytes, but it declines as oocytes mature. The objective of our study was to increase the efficiency of sheep blastocyst production after in vitro maturation/fertilization (IVM/IVF) by oocyte selection before maturation. Cumulus oocytes complexes (COCs) were aspirated from surface follicles (2-6 mm diameter) of sheep ovaries in aspiration media [TCM-199, Dulbecco’s phosphate-buffered saline (PBS), 0.3% BSA, heparin (10 μg per ml) and gentamicin (10 μ per ml). Only oocytes having more than 5 layers of cumulus cells and granular homogenous ooplasm were exposed to BCB stain diluted in DPBS (DPBS with 0.4% BSA) for 90 min at 38.5o C in a humidified air atmosphere; those with or without blue coloration of the cytoplasm were designated as BCB+ or BCB-, respectively. The oocytes were exposed to 13, 26 and 39 µM BCB. The maturation and cleavage rate of 13 μM (n=103), 26 μM (n=125) and 39 μM (n=97) BCB+ sheep oocytes was higher than those in 13 μM (n=103), 26 μM (n=125) and 39 μM (n=97) BCB-oocytes and control group (n=92). The blastocyst development rate of 26 and 39 μM BCB+ oocytes was significantly (P<0.05) higher than those in 26 and 39 μM BCB- oocytes suggesting that the staining of sheep cumulus oocyte complexes with BCB before in vitro maturation may be used to select developmentally competent oocytes for IVF.