Mono-2-ethylhexyl phthalate induces oxidative stress responses in human placental cells in vitro.
Di-2-ethylhexyl phthalate (DEHP) is an environmental contaminant commonly used as a plasticizer in polyvinyl chloride products. Exposure to DEHP has been linked to adverse pregnancy outcomes in humans including preterm birth, low birth-weight, and pregnancy loss. Although oxidative stress is linked to the pathology of adverse pregnancy outcomes, effects of DEHP metabolites, including the active metabolite, mono-2-ethylhexyl phthalate (MEHP), on oxidative stress responses in placental cells have not been previously evaluated. The objective of the current study is to identify MEHP-stimulated oxidative stress responses in human placental cells. We treated a human placental cell line, HTR-8/SVneo, with MEHP and then measured reactive oxygen species (ROS) generation using the dichlorofluorescein assay, oxidized thymine with mass-spectrometry, redox-sensitive gene expression with qRT-PCR, and apoptosis using a luminescence assay for caspase 3/7 activity. Treatment of HTR-8 cells with 180μM MEHP increased ROS generation, oxidative DNA damage, and caspase 3/7 activity, and resulted in differential expression of redox-sensitive genes. Notably, 90 and 180μM MEHP significantly induced mRNA expression of prostaglandin-endoperoxide synthase 2 (PTGS2), an enzyme important for synthesis of prostaglandins implicated in initiation of labor. The results from the present study are the first to demonstrate that MEHP stimulates oxidative stress responses in placental cells. Furthermore, the MEHP concentrations used were within an order of magnitude of the highest concentrations measured previously in human umbilical cord or maternal serum. The findings from the current study warrant future mechanistic studies of oxidative stress, apoptosis, and prostaglandins as molecular mediators of DEHP/MEHP-associated adverse pregnancy outcomes.
Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI 48109-2029, USA. ltetz@umich.edu
Lauren M
LM
Tetz
Adrienne A
AA
Cheng
Cassandra S
CS
Korte
Roger W
RW
Giese
Poguang
P
Wang
Craig
C
Harris
John D
JD
Meeker
Rita
R
Loch-Caruso
D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives* / Q000633:toxicity; D005260:Female; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D010920:Placenta / Q000187:drug effects* / Q000378:metabolism; D010968:Plasticizers / Q000633:toxicity*; D011247:Pregnancy; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013941:Thymine / Q000378:metabolism
D010968:Plasticizers; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D004051:Diethylhexyl Phthalate; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; C016599:mono-(2-ethylhexyl)phthalate; D013941:Thymine