Disturbances of cow oocyte maturation by phytoestrogens

摘要

The aim of the study was to elucidate the influence of different phytoestrogens (PEs) such as izoflavons (represented by genistein), stilbens (represented by resveratrol (RES)), lignans (represented by enterodiol) and coumestans (represented by coumstrol) on the maturation process of isolated bovine oocytes. We assumed that their influence on the rate of oocyte growth and maturation would be related primarily to their estrogenic activity (isoflavones and coumestans are similar to the 17 beta estradiol - E-2, the most potent oestrogen). Eighty to one hundred oocytes were cultured in 4 ml of the medium in six-well multidishes. Cumulus oocyte complexes (COCs) were matured at 39 degrees C in humidified air containing 5% CO2 for 24 hours. Four phytoestrogens were tested at two concentrations: 10 mu g/ml and 100 mu g/ml. These results clearly show that there is no significant relation between PEs and the survival of cow oocytes. However, under the influence of different PEs the expansion of oocytes was suppressed, especially when genistein and coumestrol were introduced into the culture medium. It was noted that the addition 4 the phytoestrogens into the medium decreased the rate of oocyte maturation. The highest increase of immature oocytes (p <= 0.05) was noted after the addition of coumestrol (30.77%) and genistein (20%) (fig. 4). The most pronounced suppression of oocyte maturation by genistein and coumestrol observed in our research indicates, therefore, that there is a direct relationship between the potency of the estrogenic activity of particular PEs and the inhibition of oocyte maturation. We concluded from our studies that PEs may disturb the conception and fertilisation rate in the cow by prolonging cow oocyte maturation.