Влияние продолжительности воздействия циклогексимида и 6-диметиламинопурин (6-ДМАП) на развитие клонированных эмбрионов крупного рогатого скота

Cycloheximide and 6 ‐ dimethylaminopurine (6 ‐ DMAP) are widely used in protocols of somatic cell nuclear transfer (SCNT) for inhibition of maturation promoting factor (MPF) activity in SCNT-oocytes in the post-activation period of their culture. Nevertheless, you should remember that these agents have a wide range of activity and can conflict with other cell processes. Therefore, a definition of the optimal period of culture of SCNT-oocytes with the previously mentioned inhibitors may help to prevent the undesirable negative consequences. In this research the effects of cycloheximide (10 µg/ml) and 6 ‐ DMAP (2mM) treatments duration (3.0, 4.0 or 5.0 h) on the reprogramming of somatic nuclear was estimated by the cleavage and blastocyst rates, and by the total cell number and a level of apoptotic cell in the obtained cloned blastocysts. The cleavage rate did not differ between the experimental groups, varying from 63.7 to 77.0 %. Also, there was not found an effect of treatment duration of the investigated factors on the development of activated SCNT-oocytes before blastocyst stage. For 3-hr treatment, the blastocyst rate was 19.6 ± 1.8%. The prolonged up to 4 and 5 hours duration did not change this rate. Meanwhile, we found out the effect of culture duration with сycloheximide and 6 ‐ DMAP on quality of cloned embryos. In case of 3-hr treatment, the total cell number in cloned blastocyst was 58.8 ± 2.4. With prolongation of duration up to 4 hours the result was growing up to 76.6 ± 1.4 (p<0.05), but prolongation up to 5 hours reduced the total cell number in blastocyst as compared to that in 4-hr group (p<0.05). The apoptosis rate had no difference between the treated groups and had its variety between 5.4 to 7.0 %. Our date indicate that efficiency of bovine cloned embryo production depends on duration of 6-DMAP and cycloheximide treatment of the SCNT-oocytes in the post-activated period of their culture. The optimal duration according to the described protocol of SCNT for the best quality of embryos is 4 hours.