Relationship between changes of culture temperature and structure of MII human oocytes¬ð spindles

    ZHU Liang, CHEN Shiª²Ling, XING Fuª²Qi, DU Jianª²Xin, GUO Yuª²Hong

    1Department of Gynecology & Obstetrics, The 306 Hospital of PLA, Beijing 100101, China, 2Assisted Reproductive Technology Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China

    ¡¾Abstract¡¿ AIM: To observe the effect of the environmental temperature on spindles in MII oocytes. METHODS: The structural changes of the MII unfertilized oocytes¬ð spindles were examined at the room temperature in 20 oocytes from 40 patients after regular in vitro fertilization. Three experiment groups were set by different keeping time (0, 5, 10 min) after the disappeaerance of spindles at the room temperature. The first group included 8 oocytes which were rewarmed immediately after the disappearance of the spindle. The second group included 6 oocytes which were rewarmed after 5 min of the disappearance of the spindle. The third group included 6 oocytes which were rewarmed after 10 min of the disappearance of the spindle. The control group included 18 MII unfertilized oocytes which had been kept at 37¡æ during the 30 min of examination of the spindles. RESULTS: The spindles of the 20 unfertilized MII oocytes disappeared after a 5ª²minute exposure to the room temperature. The 8 oocytes¬ð spindles all reappeared in group 1 and so did the 6 oocytes¬ð spindles in group 2. Only half of the oocytes¬ð spindles reappeared in group 3. In the control group, the 18 oocytes that had been kept at 37¡ãC for 30 min did not disappear. CONCLUSION: Spindles are exquisitely sensitive to the changes of temperature and lowering the room temperature may lead to the disappearance of spindles. The reappearance of spindles tends to decrease with the prolongation of low temperature. ......