Effects of Chemical Activation Treatment on Development of Swamp Buffalo (Bubalus bubalis) Oocytes Matured In Vitro and Fertilized by Intracytoplasmic Sperm Injection

• Published in: Reproduction in domestic animals Vol. 46; no. 1; pp. e67 - e73
• Main Authors: Liang, YY, Ye, DN, Laowtammathron, C, Phermthai, T, Nagai, T, Somfai, T, Parnpai, R
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2011
• Subjects: Adenine - analogs & derivatives; Adenine - pharmacology; Animal reproduction; Animals; Blastocyst - cytology; Blastocyst - physiology; Buffalo; Buffaloes; Cell Count; Cells, Cultured; Cellular biology; Cleavage Stage, Ovum - physiology; Cycloheximide - pharmacology; Embryo Culture Techniques - veterinary; Ethanol - pharmacology; Female; In vitro fertilization; Ionomycin - pharmacology; Oocytes - drug effects; Oocytes - physiology; Oocytes - ultrastructure; Protein Kinase Inhibitors - pharmacology; Sperm Injections, Intracytoplasmic - veterinary
• ISSN: 0936-6768; 1439-0531
• DOI: 10.1111/j.1439-0531.2010.01636.x

The objective of this study was to optimize the activation protocol for buffalo oocytes after intracytoplasmic sperm injection (ICSI). The release of the second polar body (PB) at 3, 6 and 9 h after ICSI of in-vitro matured oocytes activated either with 5 μm ionomycin (Io) or with 7% ethanol (EtOH) was preliminary examined. The highest rate of second PB extrusion occurred at 3 h of activation, and the second PB extrusion in EtOH group was significantly higher than that in Io group. Oocytes that extruded the second PB were selected and cultured either with 1.9 mm 6-dimethylaminopurine (6-DMAP) for 3 h or with 10 μg/ml cycloheximide (CHX) for 5 h. Significantly higher rate of oocytes formed 2 pronuclei in EtOH combined with CHX (EtOH + CHX) (62%) group compared to those of Io + CHX (42%) and EtOH + 6-DMAP (48%) groups (p < 0.01) whereas Io + 6-DMAP group showed intermediate value (58%). Significantly higher blastocyst formation rates were obtained in Io + 6-DMAP (29%) and EtOH + CHX (24%) groups than in Io + CHX (6%) and EtOH + 6-DMAP (17%) groups. Our results indicate that buffalo ICSI oocytes are effectively activated by combination treatment of Io with 6-DMAP and EtOH with CHX resulting in the highest cleavage and blastocyst formation rates.