ABSTRACT
Endocrine disrupting chemicals (EDCs) are a class of chemical substances widely present in daily-life environment, and can enter human body through various pathways, posing a threat to reproductive development and health. Oxidative stress (OS) is one of the most important fundamental mechanisms underlying the reproductive toxicity of EDCs. Numerous studies have found that exposure to EDCs can increase the levels of reactive oxygen species (ROS) in human reproductive system and reduce the activity and quantity of multiple enzymatic antioxidants, leading to oxidative stress and inducing damage to the reproductive system at various levels such as DNA and cells. Many research results have shown that supplementing food-derived non-enzymatic antioxidants can reduce ROS levels and increase the activity of enzymatic antioxidants, thereby reduce OS levels, and further repair EDCs-induced reproductive damage. In addition, many food-derived antioxidants are important elements involved in reproductive physiological activities and have protective effects on reproductive health. This paper summarized the reproductive toxicity of EDCs, including damage to reproductive cells, interference with hormone action, and influence on reproductive-related epigenetic regulation, elaborated the relationship between OS and reproductive toxicity of EDCs, and further summarized the alleviating effects and related mechanisms of food-derived antioxidants such as vitamins, trace elements, and plant polyphenols and pigments against reproductive toxicity of EDCs, aiming to provide a theoretical and scientific basis for prevention and treatment against reproductive toxicity of EDCs.
ABSTRACT
Background Exposure to perfluoroalkyl and polyfluoroalkyl substances (PFAS) during pregnancy might affect thyroid-related hormone levels in pregnant women. However, most previous studies focused on the effects of PFAS containing 8-10 carbon atoms, and few studies have estimated the associations between PFAS with longer carbon chain and thyroid-related hormone levels. Objective To examine the associations between PFAS exposure and thyroid-related hormones in pregnant women. Methods The present study was based on the Jiashan Birth Cohort from September 2016 to April 2018. We analyzed 13 PFAS in maternal blood samples (n=781) by high-performance liquid chromatography-tandem mass spectrometry, as well as total triiodothyronine (T3), total thyroxine (T4), free T3 (FT3), free T4 (FT4), thyroid stimulating hormone (TSH), thyroglobulin antibody (TG-Ab), and thyroid peroxidase antibody (TPOAb) by electrochemiluminescence immunoassay. PFAS were divided into three groups:low concentration, medium concentration and high concentration according to the tertile of their concentrations. We estimated the associations between PFAS concentrations and thyroid-related hormones in pregnant women by multiple linear regression. Results In the multiple linear regression models, a change in perfluorododecanoic acid (PFDoA) concentrations from the low concentration group to the high concentration group was associated with a −0.10 (95%CI: −0.20, 0) nmol·L−1 change in T3, −0.15 (95%CI: −0.28, −0.02) pmol·L−1 change in FT3, and −3.02 (95%CI: −5.66, −0.39) pmol·L−1 change in FT4, respectively. A change in perfluorotridecanoic acid (PFTrDA) concentrations from the low concentration group to the high concentration group was associated with a −0.10 (95%CI: −0.20, 0) nmol·L−1 change in T3. Compared with the low concentration group, the concentration of T4 in the medium concentration group of perfluorohexane sulfonate (PFHxS) increased by 6.10 (95%CI: 0.44, 11.75) nmol·L−1. No statistically significant associations were found between PFAS and TSH concentration. The negative associations of PFAS with thyroid-related hormones were more pronounced in pregnant women with positive TG-Ab and/or TPOAb. Conclusion Exposure to PFAS during pregnancy may affect thyroid-related hormone homeostasis in pregnant women, and the effect is stronger in TG-Ab and/or TPOAb-positive pregnant women.
ABSTRACT
Objective To compare the efficacy and safety of tranexamic acid(TA)and norethisterone(NET)for the treatment of patients with ovulatory menorrhagia in China. Methods Onehundred and thirty one patients with proven ovulatory menorrhagia from gynecologic clinics of 5 teaching hospitals located in 4 different cities in China were enrolled during Jul 2004 to Dec 2006.Ameng them 128 completed the study.Patients were randomly divided into two therapeutic regimen groups:TA 1g thrice daily during menstrual cycle days(D)1-5,69 cases;or NET 5 mg twice daily on D19-26.59 cases.The drugs were administered for 2 consecutive cycles,then withdrawn and patients were followed-up for 1 more cycle.Data on menstrual blood loss [ estimated by pictorial blood assessment chart(PBAC)],length of menstrual periods,quality of life(QOL)evaluated by a 6 item health-related questionnaire were collectedbefore,during each cycle and were compared.Results Both treatments led to significant decreases of mean PBAC scores and shorter duration of menstrual periods,and improved the QOL ranking during the twotreatment cycles.The mean percentages of PBAC decrements in the TA first and second cycles were significantly greater than those in the NET corresponding cycles(35%VS 17%,P=0.004;4J4%VS 34%,P=0.04 respectively).The success rate of TA second cycle was higher than that of the NET second cycle (41%VS 24%,P=0.04).Improvement of QOL ranking in the TA first cycle was also significantly better than those in the NET first cycle ( P=0.03).The percentage of patients with at least 1 adverse event in TA group(19%)was significantly lower than that in NET group(35%,P=0.04).Patients'willingness tocontinue the treatment in the TA second and follow-up cycles(94%,79%respectively)were significantly higher than those in the corresponding cycles of NET groups(79%,59%respectively;P=0.01,P=0.02).Conclusion The regimen of TA 3 g daily during menstrual days 1-5 is a more effective and tolerable treatment than luteal phase norethisterone for patients with ovulatory menorrhagia.