Effects Of Gonadotrophin Priming And Maturation Culture System On Mouse GV Oocyte Maturation In Vitro

With the applications of embryo biotechnology in human assistant reproduction and animalreproduction, oocyte in vitro maturation has become a critical step. Although there were greatprogresses on mammal oocyte in vitro maturation researches, the efficiency was still very low andmuch of problem on IVM still remained to be elucidated. Today, it is thought that the main factoron oocyes development competence is oocyte intrinsic quality that is mainly determined by thefollicular origin. In the present research, we use PMSG and hCG to mimic FSH and LH,respectively, and use immature KM (kunming strain) mouse as an animal model, to study theeffects on of oocyte origin and different culture systems on mouse cumulus-oocyte complexes,oocyte chromatin configurations, and oocyte nuclear and cytoplasm maturation by employinggonadotrophin stimulation, oocyte in-vitro maturation and artificial activation. These researcheswill provide a theoretical and practical basis on selecting immature oocytes and optimizing in-vitromaturation conditions.The results are as follows:1. Ovary stimulation increases the percentage of C⁺ type oocytes and decrease the percentageof C^- type oocytes.2. Ovary stimulation increases the percentage of SN oocytes chromatin configuration allthree types of oocyte-cumulus complexes.3. Ovary stimulation improves nuclear maturation competence of C⁺ and C^- type oocytes,but can not improve the nuclear maturation competence of C^+/- type oocytes. Ovarystimulation improves the rate of pronuclear formation after parthenogentic activation in allthree types of oocytes.4. When PMSG priming combined with hCG priming, hCG improves the pronuclearformation after oocyte in vitro maturation and parthenogentic activation, but does notimprove the maturation rate when compare with PMSG priming or hCG priming alone.5. To C⁺ type oocytes derived from nature cycle animals, there is no significant differencebetween oocyte maturation rate in induced maturation (IM) and oocyte maturation ratethrough passive matuation(PM), but oocyte maturation rate through spontaneousmaturation (SM) is signicantly lower than that of through IM and PM To C⁺ type oocytesderived from ovary stimulation animals, there is no significant difference between oocyte maturation rate through SM and through PM, but oocyte maturation rate through IM issignicanfly higher than that of through SM and PM. To C^+/- type oocytes derived fromnature cycle animals, there are significant difference among the oocyte maturation ratethrough IM, SM and PM. To C^+/- type oocytes derived from nature cycle animals, thereare no significant difference among the oocyte maturation rate through IM, SM and PM.To C^- type oocytes, whether derived from nature cycle or from ovary stimulation animals,there are no significant difference between the oocyte maturation rate through IM andPM.6. To pronuclear formation rate after oocyte in vitro maturation 18 hours and parthenogenticactivation, oocytes derived from SM is significantly higher than oocytes from PM,oocytes derived from IM is significantly lower that of oocytes detrived from PM and SM.