Perfluorotetradecanoic acid exposure to adult male rats stimulates corticosterone biosynthesis but inhibits aldosterone production

Perfluorotetradecanoic acid (PFTeDA) is a novel perfluoroalkyl substance that ubiquitously exists in the environment. However, whether PFTeDA affects adrenal cortex function remains unclear. Male Sprague-Dawley rats (age of 60 days) were daily administered with PFTeDA (0, 1, 5, and 10 mg/kg body weight) through gavage for 28 days. PFTeDA did not change body and adrenal gland weights. PFTeDA markedly elevated serum corticosterone level at 10 mg/kg but lowering serum aldosterone level at this dosage without influencing serum adrenocorticotropic hormone level. PFTeDA thickened zona fasciculata without affecting zona glomerulosa. PFTeDA remarkably upregulated the expression of corticosterone biosynthetic genes (Mc2r, Scarb1, Star, Cyp21, Cyp11b1, and Hsd11b1) and their proteins, whereas downregulating aldosterone biosynthetic enzyme Cyp11b2 and its protein, thereby distinctly altering their serum levels. PFTeDA markedly downregulated the expression of antioxidant genes (Sod1 and Sod2) and their proteins at 10 mg/kg. PFTeDA significantly decreased SIRT1/PGC1α and AMPK signaling while stimulating AKT1/mTOR signaling. Corticosterone significantly inhibited testosterone production by adult Leydig cells at >0.1 μM in vitro; however aldosterone significantly stimulated testosterone production at 0.1 nM. In conclusion, exposure to PFTeDA at male rat adulthood causes corticosterone excess and aldosterone deficiency via SIRT1/PGC1α, AMPK, and AKT1/mTOR signals, which in turn additively leads to testosterone deficiency.

Leydig cell development in pubertal male rats is blocked by perfluorotetradecanoic acid through decreasing AMPK-mTOR-autophagy pathway

Perfluorotetradecanoic acid (PFTeDA) is a type of perfluoroalkyl acid that has been linked to various health effects in animals and humans. The study aimed to investigate the potential impact of PFTeDA exposure on Leydig cell development in rats during puberty. Understanding the effects of PFTeDA on Leydig cells is crucial as these cells play a significant role in male reproductive function. Male Sprague-Dawley rats were gavaged with PFTeDA at doses of 0, 1, 5, and 10mg/kg/day from postnatal day 35 to 56. The serum hormone levels were measured and testicular transcriptome changes were analyzed by RNA-seq and verified by qPCR, and the levels of steroidogenesis-related proteins and energy regulators were measured. PFTeDA significantly reduced serum testosterone levels while slightly increasing LH levels. RNA-seq and qPCR analysis showed that genes responsive to oxidative phosphorylation (Naufa1 and Ndufs6) and steroidogenesis (Ldlr, Star, Cyp11a1) were markedly downregulated at ≥5mg/kg, while those related to ferroptosis (Alox15) and cell senescence (Map2k3 and RT1-CE3) were significantly upregulated. PFTeDA markedly reduced SIRT1 (silent information regulator 1) /PGC-1α (peroxisome proliferator-activated receptor gamma coactivator-1α) and AMPKA (AMP activated kinase A), LC3B and Beclin1 (biomarkers for autophagy) levels while increasing phosphorylated mTOR. In vitro treatment of PFTeDA at 5 μM significantly reduced androgen output of Leydig cells from 35-day-old male rats while ferrostatin 1 (10 μM) reversed PFTeDA-mediated inhibition. In conclusion, the inhibitory effects of PFTeDA on pubertal rat Leydig cell development are possibly regulated by inducing ferroptosis thereby downregulating SIRT1/AMPKA/ autophagy pathways, eventually resulting in reduced steroidogenesis.

Leydig cell function in adult male rats is disrupted by perfluorotetradecanoic acid through increasing oxidative stress and apoptosis

Perfluorotetradecanoic acid (PFTeDA) is a long-chain perfluoroalkyl compound with increased applications. Its effect on Leydig cell function and its underlying mechanism remain unclear. Male Sprague-Dawley rats (60 days old) were gavaged with PFTeDA at doses of 0, 1, 5, and 10 mg/kg/day from 60 to 87 days after birth. PFTeDA significantly reduced serum testosterone levels at 1 mg/kg and higher doses, while markedly increasing serum luteinizing hormone level at 10 mg/kg and follicle-stimulating hormone at ≥1 mg/kg. PFTeDA significantly reduced the sperm number at the cauda of epididymis at ≥1 mg/kg. PFTeDA also reduced the number of CYP11A1-positive Leydig cells due to increased apoptosis shown by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. PFTeDA significantly repressed the expression of Cyp17a1 and Star and their proteins at 1-10 mg/kg, while it increased the expression of Srd5a1 and its protein (an immature Leydig cell biomarker) at 10 mg/kg. PFTeDA markedly increased testicular malondialdehyde level, while inhibiting antioxidants (SOD1, SOD2, and CAT), triggering oxidative stress, thereby further inducing BAX and CASP3 while inhibiting BCL2, which led to cell apoptosis. PFTeDA also reduced DHH level secreted by Sertoli cells, which indirectly affected Leydig cell function. PFTeDA inhibited testosterone secretion in primary Leydig cells in vitro by increasing reactive oxygen species and inducing apoptosis at 50 μM. In conclusion, PFTeDA inhibits the function of Leydig cells by inducing oxidative stress and subsequently stimulating cell apoptosis.

Temporal trends of perfluoroalkyl acids in plasma samples of pregnant women in Hokkaido, Japan, 2003-2011

Perfluoroalkyl acids (PFAAs) are persistent organic pollutants that are used in a wide range of consumer products. Recent epidemiological studies have shown that prenatal exposure to toxic levels of PFAAs in the environment may adversely affect fetal growth and humoral immune response in infants and children. Here we have characterized levels of prenatal exposure to PFAA between 2003 and 2011 in Hokkaido, Japan, by measuring PFAA concentrations in plasma samples from pregnant women. The study population comprised 150 women who enrolled in a prospective birth cohort study conducted in Hokkaido. Eleven PFAAs were measured in maternal plasma samples using simultaneous analysis by ultra-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry. At the end of the study, in 2011, age- and parity-adjusted mean concentrations of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS) were 1.35ng/mL, 1.26ng/mL, 0.66ng/mL, 1.29ng/mL, 0.25ng/mL, 0.33ng/mL, 0.28ng/mL, and 3.86ng/mL, respectively. Whereas PFOS and PFOA concentrations declined 8.4%/y and 3.1%/y, respectively, PFNA and PFDA levels increased 4.7%/y and 2.4%/y, respectively, between 2003 and 2011. PFUnDA, PFDoDA, and PFTrDA were detected in the vast majority of maternal samples, but no significant temporal trend was apparent. Future studies must involve a larger population of pregnant women and their children to determine the effects of prenatal exposure to PFAA on health outcomes in infants and children.