In vitro maturation (IVM) of human oocytes is a laboratory method, where immature oocytes obtained after ultrasound punction of ovaries are matured using special maturation media. Immature oocytes cannot be fertilised, however with their maturation, they again become useful in clinical practice. IVM is still suboptimal, mostly because of the lack of experiments and knowledge regarding the environment of the ovaries. Anti-Müllerian hormone (AMH) is involved in the differentiation of sex of the embryo, and later on, it has an important function in the ovaries themselves, especially during folliculogenesis. Nevertheless, it is still not known whether AMH affects human oocytes. To examine this we used immunocytochemistry with fluorescent/confocal microscopy on 33 immature and 26 mature oocytes to confirm the presence of AMH receptor (AMHR2). With this, we have proven that AMH can affect oocytes. Further, we performed IVM on 91 immature oocytes with germinal vesicle (GV) acquired in the process of in vitro fertilisation in different media with or withour recombinant AMH. We found that AMH alone in the maturation media enables a 100 % maturation of immature oocytes, which shows that AMH is significantly involved in the maturation of immature oocytes. Next, after the genetic analysis on 15 immature, 45 IVM and 15 in vivo mature oocytes, we observed that AMHR2 gene is expressed in all immature (GV) and IVM oocytes, while it is absent in in vivo matured oocytes. This additionally confirms our finding that AMH affects oocyte maturation. Moreover, we discovered that AMH also affects the expression of certain important developmental genes (GDF9 and BMP4) and genes for zona pellucida (ZP1, ZP2 and ZP4) but has no effect on maturation dynamics and dimensions of oocytes. Our findings show that recombinant AMH could potentially be used in clinical practice for the improvement of the IVM method in the future.
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