In vitro maturation
In vitro maturation (IVM) is the technique of letting ovarian follicles mature in vitro.
Techniques available
The ability of in IVM depends on how mature the follicle already is. There are several stages in folliculogenesis, starting with a primordial follicle, which then becomes a primary, secondary, early tertiary (antral), late tertiary and eventually a preovulatory follicle.
If a follicle has reached the early tertiary or antral stage, IVM can be carried out. A few live births have already been made by taking small early tertiary follicles, letting them mature in vitro and subsequently fertilizing them.
However, for follicles that haven't reached the early tertiary stage, IVM is still under development. There are a lot of cellular changes in the oocyte and the rest of the cells in the follicle, which makes it very susceptible. Nevertheless, it is possible to let a primordial follicle mature to a secondary follicle outside the body by growing it in a slice of ovarian tissue. The subsequent maturity from secondary to early tertiary stage can then be supported in test-tubes. It has been suggested that photoirradiation of granulosa cells and oocytes may facilitate IVM.
