Xylene delays the development of Leydig cells in pubertal rats by inducing reactive oxidative species

Butorphanol inhibits androgen biosynthesis and metabolism in rat immature Leydig cells in vitro

Butorphanol is a synthetic opioid analgesic medication that is primarily used for the management of pain. Butorphanol may have an inhibitory effect on androgen biosynthesis and metabolism in rat immature Leydig cells. The objective of this study was to investigate the influence of butorphanol on androgen secretion by rat Leydig cells isolated from the 35-day-old male rats. Rat Leydig cells were cultured with 0.5-50 μM butorphanol for 3 h in vitro. Butorphanol at 5 and 50 μM significantly inhibited androgen secretion in immature Leydig cells. At 50 μM, butorphanol also blocked the effects of luteinizing hormone (LH) and 8bromo-cAMP-stimulated androgen secretion and 22R-hydroxycholesterol- and pregnenolone-mediated androgen production. Further analysis of the results showed that butorphanol downregulated the expression of genes involved in androgen production, including Lhcgr (LH receptor), Cyp11a1 (cholesterol side-chain cleavage enzyme), Srd5a1 (5α-reductase 1), and Akr1c14 (3α-hydroxysteroid dehydrogenase). Additionally, butorphanol directly inhibited HSD3B1 (3β-hydroxysteroid dehydrogenase 1) and SRD5A1 activity. In conclusion, butorphanol may have side effects of inhibiting androgen biosynthesis and metabolism in Leydig cells.

Demethoxylation of curcumin enhances its inhibition on human and rat 17β-hydroxysteroid dehydrogenase 3: QSAR structure-activity relationship and in silico docking analysis

Curcuminoids have many pharmacological effects. They or their metabolites may have side effects by suppressing 17β-hydroxysteroid dehydrogenase 3 (17β-HSD3). Herein, we investigated the inhibition of curcuminoids and their metabolites on human and rat 17β-HSD3 and analyzed their structure-activity relationship (SAR) and performed in silico docking. Curcuminoids and their metabolites ranked in terms of IC50 values against human 17β-HSD3 were bisdemethoxycurcumin (0.61 μM) > curcumin (8.63 μM) > demethoxycurcumin (9.59 μM) > tetrahydrocurcumin (22.04 μM) > cyclocurcumin (29.14 μM), and those against rat 17β-HSD3 were bisdemethoxycurcumin (3.94 μM) > demethoxycurcumin (4.98 μM) > curcumin (9.62 μM) > tetrahydrocurcumin (45.82 μM) > cyclocurcumin (143.5 μM). The aforementioned chemicals were mixed inhibitors for both enzymes. Molecular docking analysis revealed that they bind to the domain between the androstenedione and NADPH active sites of 17β-HSD3. Bivariate correlation analysis showed a positive correlation between LogP and pKa of curcumin derivatives with their IC50 values. Additionally, a 3D-QSAR analysis revealed that a pharmacophore model consisting of three hydrogen bond acceptor regions and one hydrogen bond donor region provided a better fit for bisdemethoxycurcumin compared to curcumin. In conclusion, curcuminoids and their metabolites possess the ability to inhibit androgen biosynthesis by directly targeting human and rat 17β-HSD3. The inhibitory strength of these compounds is influenced by their lipophilicity and ionization characteristics.

Trichlorfon blocks androgen synthesis and metabolism in rat immature Leydig cells

Trichlorfon is a widely used organophosphorus insecticide. It has been reported that it has reproductive toxicity to animal models. However, whether trichlorfon affects testosterone biosynthesis and metabolism remains unclear. In this study, we explored the effects of trichlorfon on the steroidogenesis and the expression of genes in androgen biosynthetic and metabolic cascades in immature Leydig cells isolated from pubertal male rats. Immature Leydig cells were treated with trichlorfon (0.5-50 µM) for 3 h. Trichlorfon significantly inhibited total androgen output under basal condition at 5 and 50 μM, and under LH- and cAMP-stimulated conditions at 50 μM. Trichlorfon also downregulated the expression of Star, Sod2, and Gpx1 and their proteins at 5 and 50 μM and the expression of Cyp11a1, Hsd3b1, Cyp17a1, and Srd5a1 at 50 μM. Trichlorfon significantly inhibited total androgen output at 50 μM, which was partially reversed by 400 μg/ml vitamin E, which alone had no effects on androgen output. In conclusion, trichlorfon downregulates the expression of steroidogenesis-related genes and antioxidants, which leads to a decrease in androgen production in rat immature Leydig cells.

Bisphenol F blocks Leydig cell maturation and steroidogenesis in pubertal male rats through suppressing androgen receptor signaling and activating G-protein coupled estrogen receptor 1 (GPER1) signaling

Bisphenol F (BPF) is a new analog of bisphenol A (BPA). BPA has deleterious effects on the male reproductive system, but the effect of BPF has not been studied in detail. In this study we focus on the effect of BPF on Leydig cell maturation. Male Sprague-Dawley rats were gavaged with 0, 1, 10, or 100 mg/kg BPF from postnatal days 35-56. BPF significantly reduced serum testosterone levels and sperm count in cauda epididymis at dose ≥1 mg/kg. It significantly down-regulated the expression of steroidogenic enzymes, while increasing FSHR and SOX9 levels at 10 and 100 mg/kg. Further studies showed that BPF reduced NR3C4 expression in Leydig and Sertoli cells without affecting its levels in peritubular myoid cells. BPF markedly increased GPER1 in Leydig cells at 100 mg/kg, and it significantly reduced SIRT1 and PGC1α levels in the testes at 100 mg/kg. BPF significantly inhibited testosterone production by immature Leydig cells at 50 μM after 24 h of treatment, which was completely reversed by NR3C4 agonist 7α-methyl-19-nortestosterone and partially reversed by GPER1 antagonist G15 not by ESR1 antagonist ICI 182,780. In conclusion, BPF negatively affects Leydig cell maturation in pubertal male rats through NR3C4 antagonism and GPER1 agonism.

Toxicological Effects of Technical Xylene Mixtures on the Female Reproductive System: A Systematic Review

Technical xylene is a compound of massive production that is used in applications such as petrochemical and healthcare laboratories. Exposure to xylene can cause acute and chronic effects in humans and animals. Currently available studies regarding xylene’s adverse effects with credible designs were dated almost twenty years ago. This systematic review summarizes the findings regarding the detrimental effects of technical xylene from human, animal, and in vitro studies. It recapitulated available studies with respect to the effects of xylene on the female reproductive system to stress the need for updating the current data and guidelines. Based on pre-specified criteria, 22 studies from journal databases exploring the toxic effects of xylene on menstruation, endocrine endpoints, fetal development, and reproductive functions were included for the review. It was found that related studies with a specific focus on the effects of technical xylene on the female reproductive system were insufficient. Therefore, further studies are necessary to update the existing data, thus improving the quality and reliability of risk assessment of exposure to xylene in pregnant women

Methyl tert-butyl ether inhibits pubertal development of Leydig cells in male rats by inducing mitophagy and apoptosis

Methyl tert-butyl ether (MTBE) is a widely used gasoline additive. It is considered an endocrine-disrupting chemical. Whether MTBE affects the development of Leydig cells in late puberty of males and its underlying mechanism remains unclear. Twenty-four male Sprague-Dawley rats (35 days old) were randomly allocated into four groups and were orally given MTBE (0, 300, 600, and 1200 mg/kg/day) from postnatal day (PND) 35-56. MTBE markedly reduced serum testosterone levels at 300 mg/kg and higher doses without altering the serum levels of luteinizing hormone and follicle-stimulating hormone. It mainly inhibited cell proliferation, induced mitochondrial autophagy and apoptosis, and indirectly stimulated Sertoli cells to secrete anti-Müllerian hormones, thereby significantly reducing the number of Leydig cells at 1200 mg/kg. MTBE also markedly down-regulated the expression of mature Leydig cell biomarker Cyp11a1 and Hsd3b1 and their proteins, while up-regulating the expression of immature Leydig cell biomarker Akr1c14 and its protein at 600 mg/kg and higher. MTBE significantly down-regulated the expression of cell cycle gene Ccnd1, antioxidant gene Gpx1, and anti-apoptotic gene Bcl2, while increasing pro-apoptotic gene Bax level at 1200 mg/kg. In vitro study further confirmed that MTBE can inhibit testosterone synthesis by inducing reactive oxygen species (ROS) generation, mitophagy, and apoptosis at 200 and 300 mM. In conclusion, exposure to MTBE compromises the development of Leydig cells in late puberty in male rats.

Ascorbic acid specifically reduces the misclassification of nonirritating reactive chemicals in the OptiSafe™ macromolecular eye irritation test

Recently, we showed that the addition of physiological concentrations of ascorbic acid, a tear antioxidant, to the OptiSafe™ macromolecular eye irritation test reduced the optical density (OD) of false-positive (FP) chemicals that had reactive chemistries, leading to the formation of reactive oxygen species (ROS) and molecular crosslinking. The purpose of the current study was to 1) increase the number of chemicals tested to comprehensibly determine whether the antioxidant-associated reduction in OD is specific to FP chemicals associated with ROS chemistries and 2) determine whether the addition of antioxidants interferes with the detection of true positive (TP) and true negative (TN) ocular irritants. We report that when ascorbic acid is added to the test reagents, retesting of FP chemicals with reactive chemistries show significantly reduced OD values (P < 0.05). Importantly, ascorbic acid had no significant effect on the OD values of TP or TN chemicals regardless of chemical reactivity. These findings suggest that supplementation of ascorbic acid in alternative ocular irritation test may help improve the detection of TN for those commonly misclassified reactive chemicals.