Effects of nonylphenol induced oxidative stress on apoptosis and autophagy in rat ovarian granulosa cells.

Nonylphenol (NP) is a kind of environmental endocrine disruptors which is generally recognized to cause female reproductive toxicity, but its basic mechanism has not been fully elucidated. In this study, granulosa cells (GCs) were treated with 0-70 µM NP for 24 h, the cell viability of GCs was reduced significantly, as well as increased cell apoptosis with G2/M arrest. Furthermore, NP significantly induced autophagy and the production of reactive oxygen species (ROS). However, these phenomenons were inhibited by blocking the production of ROS with N-Acetyl-l-cysteine (NAC) administration. Intriguingly, the inhibition of autophagy with 3-Methyladenine (3-MA) could enhance the apoptosis induced by NP. Moreover, the down regulating of p-Akt/Akt, p-mTOR/mTOR and subsequent up-regulation of p-AMPK/AMPK induced by NP can be rescued by pretreatment of NAC. Our findings suggested that NP promotes rat ovarian GCs apoptosis and autophagy simultaneously, which may involve the activation of ROS-dependent Akt/AMPK/mTOR pathway. Whatever, the activation of autophagy is likely to develop a protective mechanism to improve the apoptosis of rat ovarian GCs induced by NP.

Determination of urinary carnitine levels as a potential indicator of uterine fibroids caused by nonylphenol exposure.

Our previous studies have shown that uterine fibroids are associated with nonylphenol (NP) exposure, and the changes of carnitines in critical reproductive tissues and body fluids could be used to indicate the female reproductive toxicity caused by NP exposure. In this work, on the basis of further clarifying the correlation between NP exposure level and uterine fibroids, the possibility of the urinary carnitine levels as a potential indicator of uterine fibroids caused by NP exposure was discussed. The urine samples were collected from 84 female volunteers: the control group of 34 healthy women without gynecological disease and 50 uterine fibroids patients, respectively. Methods were respectively established for the determination of NP and eight carnitines in human urine samples by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that the NP level of uterine fibroids group was significantly higher than that of control group (P = 0.002), indicating that NP exposure was an important environmental factor in the occurrence of uterine fibroids. It was further found that in urine samples of the uterine fibroids group, the levels of L-Carnitine (C0), L-Acetyl-carnitine (C2), L-Octanoyl-carnitine (C8), Tetradecanoyl-carnitine (C14), Oleoyl-carnitine (C18:1) and Linoleoyl-carnitine (C18:2) had obviously increased compared with those in the control group (P < 0.001; < 0.001; < 0.001; = 0.003; < 0.001; = 0.010). The concentrations of L-Hexanoyl-carnitine (C6) and L-Palmitoyl-carnitine (C16) in the uterine fibroids group were also higher than those in the control group, although the difference was not statistically significant (P > 0.05). The results suggested that the changes in urinary carnitine levels might be a potential indicator to help to warn of the risk of uterine fibroids caused by NP exposure at the early stage.

Zinc supplement ameliorates phthalates-induced reproductive toxicity in male rats.

People are inevitably exposed to phthalates (PEs) ubiquitously existing in environment. Our previous studies, simulating the actual situations of people exposure to PEs, have shown that the sub-chronic exposure to low-doses PEs mixture (MIXPs) impaired reproductive function in male rats. Zinc is an important element in maintaining male reproductive functions. However, it is still unknown whether zinc supplement could mitigate PEs-induced male reproductive toxicity or not with sub-chronic low-dose mixture exposure. This study aimed to explore the effect of zinc supplement on the reproductive toxicity caused by sub-chronic MIXPs exposure (160 mg/(kg•body weight)/d, for 90 days) in male rats, and further to reveal the underlying mechanisms. Testosterone (T), FSH and LH in serum, early toxicity indicators in urine, PIWI proteins (PIWIL1 and PIWIL2) expression in testes and pathological examination were performed for toxicity evaluation. Steroidogenic proteins (17ß-HSD, StAR, CYP17A1, P450scc and SRD5A) were measured for mechanisms of exploration. The results indicated that zinc supplement could inhibit the T, LH, FSH level decreases in serum, abolish the effect of 5 early toxicity indicators' levels in urine, restrain the alteration of PIWI proteins expression and improve the constructional injury of testes. These effects might be relevant with the suppressed alteration of the expression of steroidogenic proteins induced by MIXPs in rat testicular cells. This work may offer further insights into reducing health risks of MIXPs exposure.

A nanofiber mat prepared from sulfonated polyaniline for solid-phase extraction of fluoroquinolones from water and biological fluids prior to their quantitation by UPLC-MS/MS.

A bifunctional sulfonated polyaniline nanofiber mat (NFM) was synthesized by oxidative polymerization and by using polyacrylonitrile nanofiber mat (NFM) as the template. The adsorption capacity of the NFM for fluoroquinolones (FQs) is distinctly improved and the adsorption was a spontaneous process. According to theoretical calculations, hydrogen bonding and ion-exchange interaction are the two major kinds of interaction mechanisms between adsorbent and FQs. The adsorption and desorption properties for FQs were systematically evaluated by adsorption isotherms and by thermodynamic and kinetic studies. The results indicate that the NFM is a viable sorbent for FQs because of rapid mass transfer and good adsorption/desorption efficiency. The NFM is re-usable for at least 20 cycles without decline in performance. Following desorption of the FQs with 10% (V/V) formic acid/acetonitrile, they were quantified by UPLC with MS/MS detection. The sorbent was applied to the solid phase extraction of the FQs norfloxacin, ciprofloxacin, ofloxacin, enrofloxacin, danofloxacin, pefloxacin, marbofloxacin, lomefloxacin and difloxacin from water and biological fluids. Figures of merit include (a) low limits of detection (0.5-1.5 ng L-1 for water, 0.016-0.052 µg L-1 for urine and serum), (b) high recoveries from spiked samples (82.3%-109.4%) with low relative standard deviations (1.1%-12.3%); (c) short extraction times (2 min), and (d) low adsorbent dosage (4 mg). Graphical abstractSchematic representation of a bi-functional sulfonated polyaniline nanofiber mat (NFM) for solid phase extraction (SPE) of fluoroquinolones (FQs) in water, urine and serum.

Chronic low-dose exposure of nonylphenol alters energy homeostasis in the reproductive system of female rats.

Nonylphenol (NP) as a confirmed endocrine disrupt chemical that causes reproductive and developmental toxicity. Previous studies focused only on short-term, high-dose exposure in vivo, or in vitro on female reproductive toxicity, which cannot accurately simulate the real human exposure scenario. The present study aims to explore NP toxicity and the underlying mechanisms of chronic low-dose NP exposure (500 µg/kg·bw/day, for 8 weeks) in the reproductive system of female rats. The results indicated that NP exposure caused female reproductive toxicity, including alterations in serum 17ß-estradiol (E2) levels, endometria hyperplasia, altered oogenesis and significant changes in the metabolic profile observed in urine, serum, uterus and ovary. Furthermore, expression of the energy-sensitive proteins carnitine palmitoyltransferase I (CPTI), adenosine 5'-monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor gamma (PPAR-γ) were found to be down-regulated in uterus under NP exposure, which suggested the impaired fatty acid oxidation. Accordingly, a comprehensive metabolomics study in key reproductive tissues and body fluids revealed that 12 metabolites were associated with energy metabolism as potential biomarkers for the evaluation of low toxicity at early stages, with L-carnitines being the most representative ones. The present findings provide evidence that chronic low-dose NP exposure can significantly disrupt energy homeostasis in females, thus offering further insights into NP reproductive toxicity.

Combined effects of simultaneous exposure to six phthalates and emulsifier glycerol monosterate on male reproductive system in rats.

Human beings are inevitably exposed to ubiquitous phthalate esters (PEs), and simultaneously ingesting high quantities of food emulsifiers via daily diet. Glycerin monostearate (GMS) is a widely used food emulsifier. The purposes of this study were to investigate the combined effects between the mixture of six frequently used PEs (MIXPs) and GMS on male rat reproductive system, and further to explore the underlying mechanisms. Male rats were orally administered either sodium carboxymethyl cellulose as controls or MIXPs at three different low-doses with or without GMS (200mg/kg/d) by gavage. The 15-week exposure of MIXPs caused male reproductive toxicity in a dose- and time-dependent manner, including the decrease of serum testosterone and morphological damage of testis. Metabonomics analyses of urine and Western blotting analyses of steroidogenic proteins (StAR, P450scc, CYP17A1, 17ß-HSD and P450arom) indicated that MIXPs exposure down-regulated the expression of steroidogenic proteins, and might alter androgen metabolism. The results also showed that the presence of GMS exacerbated the toxicities of MIXPs to male rat reproductive system. These findings suggest that food emulsifier GMS could enhance the toxic effects of MIXPs on male hormone biosynthesis.