RESUMO
The mechanisms by which genistein, a phytoestrogen, affects fetoplacental development adversely are still poorly understood. It is reported that genistein ingestion modulates thyroid functions, leptin hormone, C-reactive protein, and thyroxin kinase activities. In this study, we evaluated changes in serum and placental insulin-like growth factor-I (IGF-1), placental growth factor (PIGF), and soluble fms-like tyrosine kinase-1 (sFLT-1) in pregnant rats exposed to genistein using ELISA. According to the treatments, Rats were divided into control, 2 mg genistein, and 4 mg genistein groups. Genistein groups were administered with the doses orally from gestational day (GD) one onwards until sacrifice, while the control group received an equal volume of distilled water the vehicle. At GD-12, GD-16, and GD-20, serum samples and placenta homogenates were prepared from maternal blood samples and the placenta and were analysed to determine the concentration of IGF-1, sFLT-1, and PIGF. Serum IGF-1 and PIGF were both increased in all genistein groups at GD-12 and GD-16, and at GD-20 in the 4 mg group. However, serum IGF-1and PIGF levels were decreased in the placenta from all genistein groups at GD-20. Placenta sFLT-1 levels increased at both GD-16 and GD-20 in genistein-treated rat serum. An initial decrease in placental sFLT-1 at GD-12 was followed by an increase at GD-16 and finally a decrease at GD-20 in all genistein-treated rats. The sFL-1/PlGF ratio in placenta samples of genistein-exposed rats was decreased at GD-16 and increased at GD-20, while the reverse was recorded in the serum sample at the same gestational periods. The fetoplacental growth disruption mechanism of genistein can be partly explained by its interference with placental growth factor signalling.
