Human Reproduction：冷藏未成熟卵子可增加怀孕率
英国爱丁堡大学科学家首次发现未发育成熟的人类卵子可冷藏保存，解冻后可以人工方式培殖。这种新方法比传统的体外人工受精方法能多贮存数百颗卵子，科学家希望能为生育保存技术带来改革，曾患癌或更年期妇女仍可望生育。
据香港《文汇报》报道，新技术采用的是未完成发育的卵子，与现时体外人工受精技术采用成熟卵子的做法不同。在冷冻过程中，前者的存活率较后者高，所以较年长的女性在新技术的帮助下，怀孕机会较高。女性可避开更年期，延迟怀孕，安心发展事业。
冷藏成功数百卵子
科学家在实验室用新技术培育了数百颗人类卵子，他们先从女性子宫中，抽取带有发育未完成卵子的部分，并将之储存起来。很久以后再拿出来解冻，受精后再植回子宫里。
另外，曾经患癌的女性也可受惠。强力抗癌药会摧毁卵巢滤泡，女性怀孕无望，但有了新技术，曾受电疗和化疗的女性也可怀孕。
按照目前的做法，医生会替患癌女性抽取子宫组织，将之雪藏，等候抗癌治疗后，才把组织植回子宫，但这种做法有可能会触发癌症复发。然而新方法下组织里的未成熟卵子可先在实验室里培植，检查过没有患癌后，才接受人工受精。
负责研究的特尔弗医生在学术期刊《人类繁殖》（Human Reproduction）写道，虽然新技术是项重大突破，但须待更多研究确证，才能在临床上使用，需时约5年。（来源：中新网）
生物谷推荐原始出处：
（Human Reproduction），2008 23(5):1151-1158，Evelyn E. Telfer，K. Joo Thong
A two-step serum-free culture system supports development of human oocytes from primordial follicles in the presence of activin
1 Institute of Cell Biology, The Darwin Building, University of Edinburgh, The King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK 2 Assisted Conception Programme, The Royal Infirmary, 49 Little France Crescent, Old Dalkeith Road, Edinburgh, UK
3 Correspondence address. Tel: +44-131-650-5393; Fax: +44-131-650-8650; E-mail: evelyn.telfer@ed.ac.uk
BACKGROUND: The objective of this study was to determine whether follicles grown within human ovarian cortical strip culture for 6 days in serum-free medium could be isolated at the secondary stage of pre-antral development and grown in vitro to the late pre-antral/early antral stage during a 4 day culture period.
METHODS: Ovarian cortical biopsies were obtained from six women aged 26–40 years, with informed consent, during elective Caesarean section. Small tissue slices of ovarian cortex, with underlying stromal tissue removed, were cultured in serum-free medium for 6 days and at the end of this period pre-antral (secondary) follicles were dissected from the strips. Seventy-four intact pre-antral follicles ranging in size (66–132 µm) (mean size 100 µm ± 3.4) were selected for further culture. Follicles were placed individually within V-shaped microwell culture plates in serum-free medium in the presence (n = 38) or absence (n = 36) of 100 ng/ml of human recombinant activin A.
RESULTS: Pre-antral follicles grown for 4 days in the presence of activin A grew to a larger size (mean diameter 143 µm ± 7.4) than those grown in control medium (mean diameter 111 µm ± 8) (P < 0.005). Ninety percent of follicles cultured in the presence of activin A increased in size during the first 2 days of culture compared with only 36% of follicles in control medium (P > 0.005). Of the follicles surviving the entire culture period, 30% of those cultured in the presence of activin A showed normal morphology with intact oocytes and antral formation. None of the follicles grown in control medium developed antral cavities and >90% of those follicles collected at the end of the culture period showed signs of oocyte degeneration.
CONCLUSIONS: The results reported here demonstrate that under certain conditions, it is possible to achieve accelerated oocyte/follicle development from human primordial/primary follicles. This provides the first encouraging step towards achieving full in vitro growth of human oocytes.
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