| A large amount of pesticides is applied to agricultural, residential and public health protection sites in the world. Pesticides are deliberately released into the environment, contributing to the contamination of food, water, soil and air. The residues of many pesticides are often found in the environment and biota. An increasingly number of studies has shown that pesticides act as endocrine disruptors, which interfere with the hormone system and can cause birth defects, reproductive and developmental disorders. Gonadotropin hormones include follicle-stimulating hormone (FSH) and luteinizing hormone (LH) that are secreted by pituitary gonadotrope cells in response to gonadotropinreleasing hormone (GnRH) and play critical roles in regulation of reproductive function and sexual development in vertebrates. Epidemiological investigation found statistically significant positive associations between the levels of organochlorine pesticides and LH or FSH in human. However, the mechanism of the action of organochlorine pesticides at environmentally relevant doses on gonadotropin hormones biosynthesis remains unclear. Animal studies indicated that exposure to benzimidazole or triazole fungicides led to postimplantation loss, embryo absorption and perinatal death of pups, suggesting the potentially deleterious effects of these fungicides on placenta. Placenta is a unique endocrine organ and is responsible for maintaining pregnancy and embryo development during pregnancy. However, there is scant information regarding mechanisms of the toxicity of pesticides to placenta. In the present study, we utilized the immortalized mouse gonadotrope cell line LPT2 as an in vitro bioassay system to screen the effects of organochlorine pesticides on the expression of gonadotropin subunit genes and hormones synthesis. We also employed the human trophoblast cell to test the effects of benzimidazole and triazole fungicides on cytotoxicity, cell cycle, migration and invasion, as well as the expression of regulators.Previous studie has showed that FSH and LH levels changed after exposed dichlorodiphenyltrichloroethane (DDT) analogues. The expression of gonadotropin subunit genes (FSHβ, LHβ and Cgα genes) is the rate-limiting step of FSH and LH biosynthesis. However, the harmful effects and mechanisms of DDT analogues on the expression of those genes remain unknown. In the present study, we investigated the gonadotropin subunit genes levels in gonadotrope cells after exposed to p,p’-DDT,o,p’-DDT,p,p’-dichlorodiphenyldichloro-ethylene (p,p’-DDE) and methoxychlor (MXC). The results showed that p,p’-DDT and MXC stimulated FSHβ,LHβ and Cgα genes expression in a dose-dependent manner at test concentrations ranging from 10-9 to 10-7 mol/L. After exposed to p,p’-DDT or MXC, the induction of gonadotropin subunit genes expression required the activation of extracellular signal-regulated kinase (ERK). The present study indacated that p,p’-DDT and MXC regulated gonadotropin genes expression and hormones synthesis through ERK pathway in gonadotrope cells.Benomyl and its major active metabolite carbendazim are benzimidazole fungicides that are used throughout the world against a wide range of agricultural fungal diseases. And those two fungicides are known as reproductive toxicants and do harmful effects on human body via food contamination, environmental contamination or occupation exposure. Placental trophoblast cells are critical for the fetal-maternal interactions that determine reproductive success. However, there is little information regarding the toxicity of benzimidazole fungicides to human placenta. In the present study, we utilized human placental tropholbast cell line HTR-8/SVneo to screen the effects of benomyl and carbendazim on cell viability, cell cycle, apoptosis, cell migration, invasion and protease genes expression. The results showed that both benomyl and carbendazim decreased the viability of tropholbast cells and reduced the percentages of cells in G0/G1. Benomyl and carbendazim induced trophoblast cell apoptosis in a dose-dependent manner. The migratory and invasion ability of trophoblast cell was significantly inhibited by benomyl and carbendazim. We further found that benomyl and carbendazim changed the expression levels of MMPs/TIPMs, uPA/PAI-1 and adhesion molecules (integrin α5 and β1) in HTR-8 cells. These fingdings suggest that benzimidazole fungicides may pose a risk to human reproductive health.At present triazole fungicides are one of the top ten classes pesticides used wildwide. Triazole fungicides have many negative effects on mammalian reproduction. However there is limited information regarding the detrimental effects of triazole fungicides on human placenta, such as trophoblast function. Tebuconazole (TEB) is a common triazole fungicide that has been extensively used for the control of plant pathogenic fungi in agriculture. In the present study, we showed that the cell viability was reduced of human placental trophoblast cell line HTR-8/SVneo (HTR-8) after exposure to TEB. And TEB disturbed normal cell cycle distribution and induced apoptosis of HTR-8 cells. The results also showed that TEB decreased Bcl-2 protein expression and induced Bax protein levels in HTR-8 cells, suggesting that this chemical induced cell apoptosis of trophoblast via mitochondrial pathway. Importantly, we found that exposure to TEB significantly decreased the invasive and migratory capacities of HTR-8 cells. Treatment with TEB altered the expression of key regulatory genes, such as MMP-2, MMP-9, TIMP-1, TIMP-2, uPA, PAI-I, VEGF, PlGF, α-hCG, β-hCG, HB-EGF and TNF-α, involved in the modulation of trophoblast functions. This work reveals that TEB decreases human trophoblast invasion and migration via disrupting placental protease systems, hormones, angiogenic factors, growth factors and cytokines. Our present study indicated that TEB had harmful effects on human placental trophoblastic cells, and TBE might have the potential risk to human pregnancy outcomes. |
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