Study Of Endocrine Disrupting Activity And Mechanism For Typical Environmental Estrogens Coexisting In Water

The serious source water pollution in China, especially the pollution by environmental estrogens, has caused widespread concerns. The environmental estrogens are of great health hazards and are hard to be removed. Environmental estrogens mainly exist as mixtures and function together with E2 in the environment and in vivo. So it is of important practical significance to study the activity when multiple environmental estrogens coexist with E2.Six typical estrogens in water source were selected, namely E2, BPA, NP, DBP, Cd, and HCB. These estrogens are of different sources, have different biological activities and play estrogenic activities by different mechanisms. First we used cell proliferation tests to determine the estrogenic activities of these chemicals and to obtain the dose-effect relationship. The results showed the selected environmental estrogens induced cell proliferation. The active dose of E2 was the lowest and estrogen effect of HCB was the highest. The dose-effect relationships of all environmental estrogens accorded with the form of a parabola. E2, BPA, NP could induce estrogen effect and were stronger than others at 48h. DBP, Cd, HCB could induce the estrogen effect and were stronger than others at 72h. DBP, Cd, HCB had cumulative effects and they showed estrogenic activities at different times. Based on the results of single environmental estrogen activity, the activity of multiple environmental estrogens coexisting with E2 was determined. The results showed that E2 decreased the estrogen effect of mixture.In order to clarify the changes of estrogenic activities for environmental estrogens mixing with E2, the mechanisms were studied. The results showed E2 could weaken estrogen effect of BPA, NP, DBP, Cd and HCB, but synergistic effect occurred when E2 and NP were mixed at 48h. In view of the effect E2 have on the other chemicals, estrogen receptor and MAPK signal channels were studied to determine the affecting mechanisms before and after mix. The results showed E2, NP, DBP, Cd and HCB all could induce cell proliferation by estrogen receptor and MAPK signal channels before and after mix. BPA induced cell proliferation by estrogen receptor, and after mix estrogen receptor and MAPK signal channels were invoked. Different chemicals invoked different downstream transcription factor before and after mix with E2, thus induced cell proliferation.When the effect of mixture on MCF-7 cells was studied, the effect of mixture on sertoli cells was studied too. Sertoli cells of testis were used to test. Cell proliferation test was used to determine the changes of activities before and after mix of E2 and BPA, NP, DBP, Cd, HCB. Before mix, Cd inhibited the proliferation of sertoli cells, the other chemicals promoted the proliferation of sertoli cells. They all could induce the cell proliferation after mix. The degree of proliferation was inconformity, so the mechanisms should be studied. The results showed E2 could affect the cell proliferation by the progress of cell cycle. BPA invoked the ERK signal channel to induce the cell proliferation, and the mechanism did not change after mix with E2. NP and DBP invoked the JNK signal channel to induce the cell proliferation, and the JNK signal channel still played after mix with E2. Cd inhibited cell proliferation by inhibiting the expression of p-ERK protein, and the inhibiting effect disappeared after mix with E2. HCB invoked the JNK signal channel to induce the cell proliferation, and the mixture of E2 and HCB inhibited cell proliferation by inhibiting the expression of p-ERK protein.In order to analyze the estrogenic activities of drinking water and ensure the safety of drinking water, the environmental estrogenic activities after mix was studied. The estrogenic activities and mechanisms of raw water, sedimentation water, filtered water, treated water, and tap water were studied. The results showed the treatment processes can reduce estrogenic activity of the raw water. Along with the treatment processes went deeper, estrogenic activity reduced. But the estrogenic activity of tap water was more powerful than treated water, illustrating physical and chemical changes have reacted in the process of transport in drinking water pipe system, and the estrogenic activities of drinking water have changed. To study the male cells toxicities are also important. The results of water sample after all treatment processes inducing the male cells toxicities showed raw water promoted the proliferation of sertoli cells. After various treatments, the water samples showed no effect on male, illustrating that the drinking water treatment processes were effective for male toxicity. Mechanisms of effect of water sample of the all treatment processes on female and male were studied. The results showed raw water, filtered water and finished water could invoke transcription factor C-Myc protein and C-Fos gene by estrogen receptor and ERK signal channel induced cell proliferation. Sedimentation water and tap water not only invoked the estrogen receptor but also invoked the ERK signal channel, invoking the c-Myc gene expression and promoting cell proliferation. The results of male toxicity of drinking water showed raw water inhibited the apoptosis of sertoli cells by invoking the JNK signal channel, inducing the expression of cyclinD1 protein and increasing the number of cells. The other treatment processes reduced the estrogen content in drinking water, so the expression of function protein decreased and no proliferation effects occurred.