| The first polar body (PbI) and the second polar body (PbII) produced by the mammalian oocyte during meiotic division have no functions during the normal development of embryo, and degenerate gradually. The polar bodies, in general, were considered as a kind of cellules with no functions completely. However Feng et al (1997) and Wakayama et al (1997, 1998) have first reported that followed by injection of PbI into the enucleated oocyte, which was injected into the head of sperm, and the recombinant oocyte could produce a mouse offspring with generational function. We established this study to investigate if it has a possibility to produce procreation with recombinant PbI.Kunming mice and ICR mice were used in the study. First of all, enough PbI with strong biological activity were obtained by interfering the animals' ovulation. Then, PbI were separated from oocytes by a biochemical method and the preservation condition for PbI was explored. Finally, the chromosome sets of PbI were recombinant into oocytes to study if they had reproductive function by using cell engineering method. 1. Isolation and preservation of oocytes from miceThe 6-8 week old Kunming mice and ICR mice that were injected with pregnant mare serum (PMSG) and human chorionic gonadotrophin (HCG). 10 hours later after injections, the cumulus oocyte complexes (COCs) of mice were collected with interval of 2 hours. The amount and morphology of PbI in oocytes were calculated and analyzed, and their vigor grade was identified by the TB staining. At the same time, COCs freshly isolated were kept at different temperatures to test if it were appropriate for preservation of oocytes. The results showed that the PbI obtained from the oocytes after injection of hCG for 12-14h were verified with the strongest vigor. If the cells were kept at the room temperature and 37℃, the vigor of PbI in COCs was vanished completely, however, if PbI in COCs were stored at 4℃, their vigor was kept strong after 48h. |
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