Effects of endocrine disrupting chemicals on expression of phospholipid hydroperoxide glutathione peroxidase mRNA in rat testes

Sex-dimorphic distribution and anti-oxidative effects of selenomethionine and Se-methylselenocysteine supplementation

Selenium (Se) is a vital trace element in human beings and is essential for protection against oxidative stress. This study aimed to investigate the accumulation and antioxidant effects of two organic seleniums, L-selenomethionine (SM) and L-Se-methylselenocysteine (SMC), through in vivo and in vitro experiments. L02 cells were pretreated with 10 nM SM or SMC for 24 h, followed by exposure to 100 nM of H₂O₂. Cell viability, apoptosis, and antioxidant capacity were detected to evaluate SM and SMC's protective effect. Organic selenium (SM and SMC) and inorganic selenium (sodium selenite, SS) were compared in terms of their in vivo accumulation and antioxidant capacity when supplemented daily and subsequently deprived in SD rats. Our results show that SM or SMC pre-treatment could significantly prevent elevated apoptosis and declined antioxidant ability. We found that organic Se supplementation resulted in higher Se accumulation than inorganic Se in the liver and kidney. The antioxidant capacity of liver and kidney tissues from rats fed with either organic selenium was significantly improved and was higher than that of SS. In summary, this study suggests that organic selenium supplements are more effective in facilitating Se accumulation in liver and kidney, enhancing antioxidant capacities, thereby protecting cells from oxidative stress. PRACTICAL APPLICATION: This study compared the antioxidant capacity of sodium selenite, L-selenomethionine, and L-Se-methylselenocysteine in vitro and in vivo. The results showed that organic selenium has a stronger antioxidant capacity and that significant differences exist in its absorption and conversion in male and female rats. Our results provide theoretical guidance for dietary supplementation of selenium.

SEXUAL DIMORPHISM IN SELENIUM METABOLISM AND SELENOPROTEINS

Sexual dimorphism, the condition in which males and females in a species differ beyond the morphology of sex organs, delineates critical aspects of the biology of higher eukaryotes, including selenium metabolism. While sex differences in selenium biology have been described by several laboratories, delineation of the effects of sex in selenium function and regulation of selenoprotein expression is still in its infancy. This review encompasses the available information on sex-dependent parameters of selenium metabolism, as well as the effects of selenium on sex hormones. Gaps in the current knowledge of selenium and sex are identified and discussed.

A systematic review on the adverse health effects of di-2-ethylhexyl phthalate

Di (ethylhexyl) phthalate (DEHP) is a global environmental pollutant. This study aims to systematically review the literature on health effects of exposure to DEHP including effects on reproductive health, carcinogenesis, pregnancy outcome, and respiratory system. The literature search was done through Scopus, ISI Web of Science, Google Scholar, PubMed, Medline, and the reference lists of previous review articles to identify relevant articles published to June 2016 in each subject area. The inclusion criteria were as follows: original research, cross-sectional studies, case-control studies, cohort studies, interventional studies, and review articles. Both human and animal studies were included. The search was limited to English language papers. Conference papers, editorials, and letters were not included. The systematic review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Overall, 152 of the 407 papers met the inclusion criteria. We provided an up-to-date comprehensive and critical assessment of both human and animal studies undertaken to explore the effects of DEHP. It revealed that in experimental studies, exposure to DEHP mainly targeted the reproductive, neurodevelopment, and respiratory systems. Human studies reported that exposure to this contaminant had carcinogenic effects and influenced neurodevelopment in early life. This systematic review underscored the adverse health effects of DEHP for pregnant women and the pediatric age group. It summarizes different response of humans and experimental animals to DEHP exposure, and some suggested underlying mechanisms.

Integrated proteomics and metabolomics analysis of rat testis: Mechanism of arsenic-induced male reproductive toxicity

Arsenic is a widespread metalloid in environment, whose exposure has been associated with a broad spectrum of toxic effects. However, a global view of arsenic-induced male reproductive toxicity is still lack, and the underlying mechanisms remain largely unclear. Our results revealed that arsenic exposure decreased testosterone level and reduced sperm quality in rats. By conducting an integrated proteomics and metabolomics analysis, the present study aims to investigate the global influence of arsenic exposure on the proteome and metabolome in rat testis. The abundance of 70 proteins (36 up-regulated and 34 down-regulated) and 13 metabolites (8 increased and 5 decreased) were found to be significantly altered by arsenic treatment. Among these, 19 proteins and 2 metabolites were specifically related to male reproductive system development and function, including spermatogenesis, sperm function and fertilization, fertility, internal genitalia development, and mating behavior. It is further proposed that arsenic mainly impaired spermatogenesis and fertilization via aberrant modulation of these male reproduction-related proteins and metabolites, which may be mediated by the ERK/AKT/NF-κB-dependent signaling pathway. Overall, these findings will aid our understanding of the mechanisms responsible for arsenic-induced male reproductive toxicity, and from such studies useful biomarkers indicative of arsenic exposure could be discovered.

The adverse effect of 4-tert-octylphenol on fat metabolism in pregnant rats via regulation of lipogenic proteins

Alkylphenols such as 4-tert-octylphenol (OP), nonylphenol, and bisphenol A are classified as endocrine-disrupting chemicals (EDCs). Digestion and metabolism of food are controlled by many endocrine factors, including insulin, glucagon, and estrogen. These factors are differentially regulated during pregnancy. The alteration of nutritional intake and fat metabolism may affect the maintenance of pregnancy and supplementation of nutrients to the fetus, and therefore can cause severe metabolic diseases such as ketosis, marasmus and diabetes mellitus in pregnant individuals. In this study, we examined the effects of OP on fat metabolism in pregnant rats. Ethinyl estradiol (EE) was also administered as an estrogenic positive control. In our results, rats treated with OP showed significantly reduced body weights compared to the control group. In addition, histological analysis showed that the amount of fat deposited in adipocytes was reduced by OP treatment. To study the mechanism of action of OP in fat metabolism, we examined the expression levels of fat metabolism-associated genes in rat adipose tissue and liver by real-time PCR. OP and EE negatively regulated the expression of lipogenic enzymes, including FAS (fatty acid synthase), ACC-1 (acetyl-CoA carboxylase-1), and SCD-1 (stearoyl-CoA desaturase-1). The levels of lipogenic enzyme-associated transcription factors such as C/EBP-α (CAAT enhancer binding protein alpha) and SREBP-1c (sterol regulatory element binding protein-1c) were also reduced in both liver and adipose tissue. In summary, these findings suggest that OP has adverse effects on fat metabolism in pregnant rats and inhibits fat deposition via regulating lipogenic genes in the liver and adipose tissue. The altered fat metabolism by OP may affect the nutrition balance during pregnancy and can cause metabolism-related diseases.

Ameliorative Effects of Curcumin on Artesunate-Induced Subchronic Toxicity in Testis of Swiss Albino Male Mice

India is one of the endemic areas where control of malaria has become a formidable task. Artesunate is the current antimalarial drug used to treat malaria, especially chloroquine resistant. The objective of the present study was to investigate the dose-dependent effect of oral administration of artesunate on the oxidative parameters in testes of adult male Swiss albino mice and ameliorative efficacy of curcumin, a widely used antioxidant. An oral dose of 150 mg/kg body weight (bwt; low dose) and 300 mg/kg bwt (high dose) of artesunate was administered for a period of 45 days to male mice, and ameliorative efficacy of curcumin was also assessed. The results revealed that artesunate caused significant alteration in oxidative parameters in dose-dependent manner. Administration of artesunate brought about significant decrease in activities of superoxide dismutase, glutathione, glutathione peroxidase, and glutathione reductase, whereas lipid peroxidation and glutathione-S-transferase activity were found to be significantly increased. The results obtained show that oxidative insult is incurred upon the intracellular antioxidant system of testis tissue by artesunate treatment. Further, administration of curcumin at the dose level of 80 mg/kg bwt along with both doses of artesunate attenuated adverse effects in male mice.

The combined effect of clothianidin and environmental stress on the behavioral and reproductive function in male mice

Neonicotinoids, some of the most widely used pesticides in the world, act as agonists to the nicotinic acetylcholine receptors (nAChRs) of insects, resulting in death from abnormal excitability. Neonicotinoids unexpectedly became a major topic as a compelling cause of honeybee colony collapse disorder, which is damaging crop production that requires pollination worldwide. Mammal nAChRs appear to have a certain affinity for neonicotinoids with lower levels than those of insects; there is thus rising concern about unpredictable adverse effects of neonicotinoids on vertebrates. We hypothesized that the effects of neonicotinoids would be enhanced under a chronic stressed condition, which is known to alter the expression of targets of neonicotinoids, i.e., neuronal nAChRs. We performed immunohistochemical and behavioral analyses in male mice actively administered a neonicotinoid, clothianidin (CTD; 0, 10, 50 and 250 mg/kg/day), for 4 weeks under an unpredictable chronic stress procedure. Vacuolated seminiferous epithelia and a decrease in the immunoreactivity of the antioxidant enzyme glutathione peroxidase 4 were observed in the testes of the CTD+stress mice. In an open field test, although the locomotor activities were not affected, the anxiety-like behaviors of the mice were elevated by both CTD and stress. The present study demonstrates that the behavioral and reproductive effects of CTD become more serious in combination with environmental stress, which may reflect our actual situation of multiple exposure.

Effect of nonylphenol on male reproduction: analysis of rat epididymal biochemical markers and antioxidant defense enzymes

The mechanism by which nonylphenol (NP) interferes with male reproduction is not fully elucidated. Therefore, the present study was conducted to evaluate the effect of NP on male reproductive organ's weight, sperm characteristics, and to elucidate the nature and mechanism of action of NP on the epididymis. Adult male Wistar rats were gavaged with NP, dissolved in corn oil, at 0, 100, 200 or 300mg/kg/day for 30 consecutive days. Control rats were gavaged with vehicle (corn oil) alone. Body weight did not show any significant change while, absolute testes and epididymides weights were significantly decreased. Sperm count in cauda and caput/corpus epididymides, and sperm motility was significantly decreased. Daily sperm production was significantly decreased in a dose-related manner. Sperm transit time in cauda epididymis was significantly decreased by 300mg/kg, while in the caput/corpus epididymis it was significantly decreased by 200 and 300mg/kg of NP. Plasma LDH was significantly increased while; plasma testosterone was significantly decreased in a dose-related pattern. In the epididymal sperm, NP decreased acrosome integrity, Δψm and 5'-nucleotidase activity. Hydrogen peroxide (H(2)O(2)) production and LPO were significantly increased in a dose-related pattern. The activities of SOD, CAT and GPx were significantly decreased in the epididymal sperm. In conclusion, this study revealed that NP treatment impairs spermatogenesis and has a cytotoxic effect on epididymal sperm. It disrupts the prooxidant and antioxidant balance. This leads oxidative stress in epididymal sperms of rat. Moreover, the reduction in sperm transit time may affect sperm quality and fertility potential.

Phospholipid hydroperoxide glutathione peroxidase gene is regulated via an estrogen and estrogen receptor signaling in cultured mouse fetuses

Although it has been suggested that the transcription of phospholipid hydroperoxide glutathione peroxidase (PHGPx), an essential antioxidant selenoenzyme, may be affected by the estrogen state in mammals, the direct mechanism underlying the regulation of the PHGPx gene by estrogens in mammalian tissues remains to be clearly elucidated. In this study, we evaluated the expression of the PHGPx mRNA in cultured mouse fetuses (embryonic days 8.5-10.5) exposed to 17β-estradiol (E(2); 0.1, 1, 10, 100, and 1,000 ng/ml); estrogen receptor (ER) agonists [propyl pyrazole triol (PPT, an ERα-selective ligand, 1 μl/ml) and diarylpropionitrile (DPN, an ERβ-selective ligand, 1 μl/ml)]; and/or ER antagonist [ICI 182,780 (ICI, 1 μl/ml)] using a whole embryo culture system. E(2)-alone treatment significantly stimulated the expressions of both ERα and ERβ mRNAs in all the cultured fetuses (p < 0.05), although the ERβ mRNA levels were higher than ERα mRNA. PHGPx mRNA expression was significantly increased in all the fetuses treated with E(2) (1-1,000 ng/ml), PPT, and DPN (p < 0.05). Furthermore, pretreatment with ICI completely blocked the E(2)-induced PHGPx mRNA expression in the fetuses. In addition, the mRNA levels of cytosolic GPx, the other intracellular antioxidant selenoenzyme, did not differ significantly from the controls by an exposure to those agents. These results suggest that the PHGPx gene is regulated via an estrogen and ER signal pathway in the cultured mouse fetus.

Anti-oxidative status and hepatic enzymes following acute administration of diethyl phthalate in olive flounder Paralichthys olivaceus, a marine culture fish

Although diethyl phthalate (DEP) is one of the most frequently used phthalates in solvents and fixatives for numerous industrial products, almost no research has been done on its biochemical toxicity in aquatic animals. Olive flounder (Paralichthys olivaceus), an important culture fish in far eastern Asian countries, were treated with intraperitoneal DEP at 0, 100, 300 or 900 mg/kg for three consecutive days and biochemical effects were assessed in the liver, kidney and serum 24 h after the final dosing. Measured parameters were mostly restricted to oxidative status and toxicity of the organs. In the hepatic tissue, there were significant increases in lipid peroxide (LPO) at 100mg/kg and above. Other hepatic parameters, which were examined, changed only after 900 mg/kg: reduced glutathione content (GSH), glutathione reductase activity (GR), glutathione peroxidase (GPx) activity increased; catalase (CAT) activity decreased. DEP also induced elevation in LPO levels at above 100 mg/kg in renal tissues; however, there was only a decrease in GR and glutathione S-transferase (GST) activities with DEP 900 mg/kg in contrast to the liver. Enzyme activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in hepatic tissues decreased in a dose-dependent manner in response to DEP at above 300 mg/kg. DEP at 300-900 mg/kg, although not uniform among parameters, caused increases in serum alkaline phosphatase (ALP), lactate dehydrogenase (LDH), AST, ALT activities and osmolality value, suggesting that DEP at these doses induced hepatic cell damage. The results indicate that 100-900 mg/kg DEP induced oxidative stress and the fish seemed to activate compensatory anti-oxidant systems to cope with the imposed substance on the liver. Such compensatory activation was not evident in the kidney. Overall, DEP was only weakly toxic to olive flounder in terms of oxidative and hepatic damage.

The effect of eurycoma longifolia Jack on spermatogenesis in estrogen-treated rats

INTRODUCTION

There is little data concerning the ability of Eurycoma longifolia Jack (EL) to reverse the inhibitory effects of estrogen on testosterone production and spermatogenesis. The aim of the present study was to determine the effect of EL on testicular histology and sperm count in estrogen-treated male rats.

METHODS

Adult male Sprague-Dawley rats weighing 200-250 g were divided into four groups of six rats each. Group A (control) was given solvent in the same manner as the treated groups were given EL. Group B was treated with EL (8 mg/kg body weight) orally. Group C was treated with estradiol (E(2)) (intramuscular dose of 500 microg/kg body weight), and group D received a combined treatment of oral EL and intramuscular E(2). After fourteen consecutive days of treatment, rats from all groups were sacrificed and subjected to spermatogenic and epididymal sperm cell counts.

RESULTS

The spermatogenic cell count in the E(2)-treated group was significantly decreased as compared to the control (p < 0.05) and EL+E(2)-treated groups (p < 0.05). A similar finding was found for the epididymal sperm count; the E(2)-treated group had a significant decrease in the count compared to the control (p < 0.05) and EL+E(2)-treated groups (p < 0.05). Rats that were treated with EL alone exhibited significantly higher sperm counts and sperm motility when compared to the control group (p < 0.05).

CONCLUSIONS

EL extract acts as a potential agent for reversing the effects of estrogen by increasing spermatogenesis and sperm counts in rats after fourteen consecutive days of treatment.