Follicular fluid the best medium of Maturation, fertilization and development of immature oocytes

In vitro maturation and development of immature oocytes, as an artificial reproduction technique, is useful especially in women who are affected by cancer and polycystic ovary syndrome. Despite using many types of in vitro media, an appropriate environment has not been reported yet. Present study was designed to assess the effect of heated human follicular fluid (hHFF), which is similar to in vivo environment for oocyte, on the maturation and fertilization potential of mouse immature oocytes.

Healthy female mice, aged 4-6 weeks, were sacrificed via cervical dislocation and their ovaries were extracted under sterile conditions. After washing, the separated immature oocytes were divided into three groups: In the first group, 236 immature oocytes were placed in culture medium contained DMEM, HCG, FSC 25%, and rFSH. In the second group, 229 immature oocytes were put in culture medium contained 100% hHFF. In the third group, 255 immature oocytes were placed in culture medium contained DMEM, HCG, rFSH, and 25% hHFF. Immature oocytes were placed in an incubator for 24 hours. Then, the stages of oocyte maturation were assessed by invert microscope and mature oocytes in each group were transferred to sperm-contained drops. After 24 hr, rate of two-cell embryos was recorded using invert microscope. Data was analyzed by Chi square test.

Maturation rate of oocytes in the second group (87.8%) was significantly higher than first (64.9%) and third (63.2%) groups (p<0.0005). The difference between first and third groups was not statistically significant (P<0.2). The formation rate of two-cell embryo in the second group (82.1%) was higher than first (50.2%) and third (54.3%) groups (p<0.002 and P<0.01, respectively).

it seems hHFF could improve in vitro maturation and fertility potential of immature oocytes and consequently the formation rate of two-cell embryos in mice, in comparison with DMEM even supplemented with 25% hHFF.