Effect Of Transplantation Of Mitochondria From Cumulus Cells On The Developmental Potential Of The Mouse Early Embryo

The object of this study was to assess the effect of mitochodria (MIT) from cumulus cells transplanted into oocyte on the developmental potential of early embryo derived from aged mouse.The Kunming mouse was used as experiment animal model and the study was carried out in two parts. In the first part of the study, apoptosis of the cumulus cells was analyzed in two methods, one was fluorescent microscope analysis after staining with Hoechst 33258, the other was flow cytometry analysis after a dual staining with Hoechst 33258 and propidium iodide. The results showed that, in both methods, the apoptosis of the cumulus cells of young mouse (2-3 months) did not statistically differ from those of old mouse (12 months) (p>0.05). It indicated the feasibility of the MIT of cumulus cells from aged mouse. However, apoptosis and necrosis still need to be taken into consideration, for it would affect the outcome of MIT. In the second part of the study, effect of MIT to the oocytes from aged mouse (12 months) was assessed in intracytoplasmic injection (ICSI) system. The result showed that the cleavage rate in MIT+ICSI group did not significantly differ from ICSI group(56.9%VS 50%, p>0.05), while the blastocyst rate was higher in MIT+ICSI than in ICSI (32.54% VS 24.977%,p< 0.05). In this part of study , a comparision study was also done between MIT and false MIT into the mouse in vivo zygotes, with a normal embryo in vitro culture without MIT as control. The result showed that the cleavage rate and blastocyst rate of false MIT was statistically lower than that of control group (39.33% VS 60%; 19.67% VS 46%; p<0.05) and MIT group (39.33%VS 67.90 ; 19.67%VS 51.54%; p<0.05), while there was no difference between the control group and MIT group (p>0.05).