| Since 1970s, the harm of environmental estrogens (EE) to health has got more and more attention of the public, and it has been a popular research theme of toxicology abroad. The third international academic session of EE was held in 1994, the nature discussed this topic specially. EE are exogenous chemicals, which could mimic or interfere the synthesis, secretion, transfer, combination, excretion and physiological function of endogenous natural estrogens. So far the determined EE comprises the following: 1. The artificial composed estrogens used clinically, such as diethylstilbestrol (DES); 2. Phytoestrogens, such as the fungal estrogen in grains; 3. The various industrial pollutants and pesticides, such as DDT, polychlorinated biphenyl, dioxin, alkyl phenol polyglycol ethers (APEs), etc. The alkylphenols (APs) is widely distributed in the environment, while the typical environmental APs pollutants are octylphenol (OP), nonylphenol (NP), bisphenol A (BPA) .It has been reported all the three APs had estrogenic activity, but their mechanism remains unclear. In order to establish a stable method of detecting the EE, and to assess APs's harm and their physiological mechanism to human, this paper adopted cell proliferation test of MCF-7 in vitro and uterus weight increase test in vivo to research the estrogenic activity of OP, NP and BPA, determined some influencing factors in the two detecting tests, provided some criteria about the standard detection of EE. Also, the paper makes some research on the function mechanism of OP, NP and BPA by tamoxifen (Tam) resistant test and apoptosis detection method. The paper comprises two parts: The first part: we established an EE detection method by MCF-7 cellsproliferation test in vitro; the three Aps's estrogen activities were determined by this method. The results were as following: 1.In the estrogen-free medium, C cell line of MCF-7 was more sensitive to E2 stimulation than A and B cell line (P<0.01). 2. The phenolsulfonphthalein in medium and the endogenous estrogen in NBS had stimulation on the cell proliferation of MCF-7. 3. The longer MCF-7 was cultured in estrogen-free medium, the more sensitive was the cell to the stimulation of estrogen, the sensitivity to estrogen-free culture time were: 4 weeks > 2 weeks > 1 weeks (P < 0.01).The results of estrogenic activity of OP, NP and BPA determined by MCF-7 cell proliferation test were as following: The lowest detectable concentrations of the three APs in the test system were different: they were 10-8M , 10-6M and 10-7M respectively, the sensitivity order was OP >BPA > NP. All the three APs were most effective at the concentration of 10-5M in promoting the proliferation of MCF-7, their relative proliferate effect were: OP (92.20%), NP (88.05%) BPA (108.01%), that means their estrogenic activity at the concentration of 10-5M are BPA> OP > NP.The result of Tam resistant test manifested that Tam could resist the estrogenic activity of the three APs, it suggested that the three APs could finish their proliferate function on MCF-7 by binding to the estrogen receptor, because their proliferate function could be resisted by the estrogen receptor antagonist Tam. The apoptosis test suggested that the three APs influenced cell proliferation of MCF-7 not only by binding to the estrogen receptor, but also by inhibiting the cell apoptosis by certain mechanism. The second part: to determine the estrogenic activity of OP by rat uterus weight increase test. 21 days old Wistar rat were adopted, OP were administrated daily by neck subdermal injection, peritoneal injection and stomach lavage for three days. The results were: The uterus weights of all thetest groups were higher than the control group (P < 0.05 or P < 0.01),this manifested that OP had estrogenic activity. The groups by neck sybderman injection had good dose-effect correlation, the group of 400mg/kg got most increase in their uterus, its uterus coefficient was 18.82, 4 fold that of the control. All the groups by stomach lavage had higher weight...
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