THE DEVELOPMENTAL COMPETENCE OF BOVINE OOCYTES MATURED IN VITRO USING THYMOSIN BETA 4

The aim of this study was to examine the effect of thymosin beta 4 (T beta 4) during in vitro maturation (WM) of oocytes and subsequent embryonic development after in vitro fertilization as well as to assess the quality of obtained blastocysts. Cumulus-oocyte complexes (COCs) were matured in vitro in 4 different media: 1. control medium; 2. control media supplemented with 50 ng/mL T beta 4; 3. control media supplemented with 0.5 mg/mL T beta 4; and 4. control media supplemented with 1 ing/mt, T beta 4. The quality of the developed blastocysts was analysed by the TUNEL method. The number of cleaved eggs was significantly higher (P<0.05) when gametes were matured in the presence of 50 ng/mL TIM than it was using the other types of media. Additionally, the largest number of blastocysts was observed when 0.5 mg T beta 4 was added to the medium (P<0.05). No significant difference was noted in the mean number of apoptotic nuclei per blastocyst or in the mean number of nuclei per blustocyst in any of the analysed groups. In conclusion, T beta 4 supplementation (50 ng/mL) in maturation medium increased the number of cleaved oocytes, and the number of blastocysts obtained increased when 0.5 mg/mL T beta 4 was used. This positive effect was not observed when a higher concentration of T beta 4 (1 mg/mL) was used.