Perinatal exposure to low doses of cypermethrin induce the puberty-related hormones and decrease the time to puberty in the female offspring

Maternal exposure to beta-Cypermethrin disrupts placental development by dysfunction of trophoblast cells from oxidative stress

As a broad-spectrum and efficient insecticide, beta-Cypermethrin (β-CYP) poses a health risk to pregnancy. It matters the mechanisms of maternal exposure to β-CYP for impacting reproductive health. The placenta, a transient organ pivotal for maternal-fetal communication during pregnancy, plays a crucial role in embryonic development. The effect of β-CYP exposure on the placenta and its underlying molecular mechanisms remain obscure. The objective of this study was to investigate the effect of β-CYP exposure on placental development and the function of trophoblast, as well as the underlying mechanisms through CD-1 mouse model (1, 10, 20 mg/kg.bw) and in vitro HTR-8/SVneo cell model (12.5, 25, 50, 100 μM). We found slower weight gain and reduced uterine wet weight in pregnant mice with maternal exposure to β-CYP during pregnancy, as well as adverse pregnancy outcomes such as uterine bleeding and embryo resorption. The abnormal placental development in response to β-CYP was noticed, including imbalanced placental structure and disrupted labyrinthine vascular development. Trophoblasts, pivotal in placental development and vascular remodeling, displayed abnormal differentiation under β-CYP exposure. This aberration was characterized by thickened trophoblast layers in the labyrinthine zone, accompanied by mitochondrial and endoplasmic reticulum swelling within trophoblasts. Further researches on human chorionic trophoblast cell lines revealed that β-CYP exposure induced apoptosis in HTR-8/SVneo cells. This induction resulted in a notable decrease in migration and invasion abilities, coupled with oxidative stress and the inhibition of the Notch signaling pathway. N-acetylcysteine (an antioxidant) partially restored the impaired Notch signaling pathway in HTR-8/SVneo cells, and mitigated cellular functional damage attributed to β-CYP exposure. Collectively, exposure to β-CYP induced oxidative stress and then led to inhibition of the Notch signaling pathway and dysfunction of trophoblast cells, ultimately resulted in abnormal placenta and pregnancy. These findings indicate Reactive Oxygen Species as potential intervention targets to mitigate β-CYP toxicity. The comprehensive elucidation contributes to our understanding of β-CYP biosafety and offers an experimental basis for preventing and managing its reproductive toxicity.

Triclosan induces earlier puberty onset in female mice via interfering with L-type calcium channels and activating Pik3cd

Triclosan (TCS) is a broad-spectrum antibacterial chemical widely presents in people's daily lives. Epidemiological studies have revealed that TCS exposure may affect female puberty development. However, the developmental toxicity after low-dose TCS continuous exposure remains to be confirmed. In our study, 8-week-old ICR female mice were continuously exposed to TCS (30, 300, 3000 μg/kg/day) or vehicle (corn oil) from 2 weeks before mating to postnatal day 21 (PND 21) of F1 female mice, while F1 female mice were treated with TCS intragastric administration from PND 22 until PND 56. Vaginal opening (VO) observation, hypothalamic-pituitary-ovarian (HPO) axis related hormones and genes detection, and ovarian transcriptome analysis were carried out to investigate the effects of TCS exposure on puberty onset. Meanwhile, human granulosa-like tumor cell lines (KGN cells) were exposed to TCS to further explore the biological mechanism of the ovary in vitro. The results showed that long-term exposure to low-dose TCS led to approximately a 3-day earlier puberty onset in F1 female mice. Moreover, TCS up-regulated the secretion of estradiol (E2) and the expression of ovarian steroidogenesis genes. Notably, ovarian transcriptomes analysis as well as bidirectional validation in KGN cells suggested that L-type calcium channels and Pik3cd were involved in TCS-induced up-regulation of ovarian-related hormones and genes. In conclusion, our study demonstrated that TCS interfered with L-type calcium channels and activated Pik3cd to up-regulate the expression of ovarian steroidogenesis and related genes, thereby inducing the earlier puberty onset in F1 female mice.

Combined exposure of beta-cypermethrin and emamectin benzoate interferes with the HPO axis through oxidative stress, causing an imbalance of hormone homeostasis in female rats

The impact of pesticides on reproductive health has been increasingly recognized. β-cypermethrin (β-CYP) and emamectin benzoate (EMB) are commonly used with agricultural workers. There are few published studies on the effects of combined poisoning of these two pesticides on the reproductive system. This study investigated the toxic effects and mechanism of β-CYP and EMB on the reproductive system of female rats based on the hypothalamic-pituitary-ovarian (HPO) axis. The hypothalamic GnRH content tended to decrease, and Kiss-1 and GPR-54 mRNA and protein expression tended to increase in exposed rats. FSH content was elevated for the pituitary gland, and Kiss-1 and GPR-54 mRNA and protein expression were enhanced in all experimental groups compared with the control group. E2 content in rat ovaries and ERα mRNA and protein expression were reduced by β-CYP and EMB. Furthermore, there were interactive effects of β-CYP and EMB on FSH and E2 release, pituitary GPR-54 mRNA and protein, and ovarian ERα mRNA expression. To investigate causes of damage, oxidative damage indicators were tested and showed that exposure to β-CYP and EMB decreased GSH-Px and SOD activities in the HPO axis, increased MDA levels in the hypothalamus and ovary together with LDH activities in the HPO axis, with an interaction effect on GSH-Px and SOD activities in the hypothalamus and pituitary gland as well as on MDA in the ovary. The above results support the screening of sensitive molecular biomarkers and evaluation of the adverse effects of pesticide exposure in greenhouse operations on reproductive health.