Proteomic analysis of indium embryotoxicity in cultured postimplantation rat embryos

Parental exposure to waterborne selenite induces transgenerational development toxicity in zebrafish offspring

Excessive selenium (Se), especially selenite form exerts great toxicity to fish. Most studies have attached considerable attention to the adverse effects of Se on parental fish. However, the transgenerational toxicity of Se on fish has been rarely reported. In the present study, zebrafish embryos were exposed to environmentally relevant concentrations of Na₂SeO₃ (0, 12.5, 25, 50, and 100 μg/L) for 120 days. And the exposed zebrafish (F0) were allowed to spawn with normal zebrafish after sexual maturity. Subsequently, the offspring (F1) were cultured in clean water for 5 days. In the F0 generation, exposure to 100 μg/L Na₂SeO₃ significantly increased the Se content in the tissues (liver, brain and gonad) and decreased the body length and weight. After parental exposure to 100 μg/L Na₂SeO₃, the increased mortality, elevated malformation rate and reduced body length were measured in F1 zebrafish. The Se content was only significantly increased in F1 larvae derived from exposed females in the 100 μg/L exposure group. The contents of thyroid hormones (THs), growth hormone (GH) and insulin-like growth factor (IGF) significantly decreased in F0 and F1 zebrafish. The transcriptional levels of genes along the hypothalamic-pituitary-thyroid (HPT) axis and growth hormone/insulin-like growth factor (GH/IGF) axis were detected to further explore the possible mechanisms of Se-induced thyroid and growth hormone disruption. The results suggest that the toxicity of Se in zebrafish can be markedly transmitted to offspring. And the transgenerational development toxicity might be different due to the differences in gender of exposed parents.

Effects of 13 developmentally toxic chemicals on the migration of rat cephalic neural crest cells in vitro

The inhibition of neural crest cell (NCC) migration has been considered as a possible pathogenic mechanism underlying chemical developmental toxicity. In this study, we examined the effects of 13 developmentally toxic chemicals on the migration of rat cephalic NCCs (cNCCs) by using a simple in vitro assay. cNCCs were cultured for 48 h as emigrants from rhombencephalic neural tubes explanted from rat embryos at day 10.5 of gestation. The chemicals were added to the culture medium at 24 h of culture. Migration of cNCCs was measured as the change in the radius (radius ratio) calculated from the circular spread of cNCCs between 24 and 48 h of culture. Of the chemicals examined, 13-cis-retinoic acid, ethanol, ibuprofen, lead acetate, salicylic acid, and selenate inhibited the migration of cNCCs at their embryotoxic concentrations; no effects were observed for acetaminophen, caffeine, indium, phenytoin, selenite, tributyltin, and valproic acid. In a cNCC proliferation assay, ethanol, ibuprofen, salicylic acid, selenate, and tributyltin inhibited cell proliferation, suggesting the contribution of the reduced cell number to the inhibited migration of cNCCs. It was determined that several developmentally toxic chemicals inhibited the migration of cNCCs, the effects of which were manifested as various craniofacial abnormalities.

Fractionation and release behaviors of metals (In, Mo, Sr) from industrial sludge

Little is known on the fate of rare metals in the environment and the associated risks. The fractionation and release of three metals of an industrial sludge were assessed. The average concentration ranges from 39.3 to 41.5 mg/kg for indium (In), 43.1-77.8 mg/kg for molybdenum (Mo), and 131.1-376.4 mg/kg for strontium (Sr). Sequential extraction results implied that In was mobile, while Mo and Sr were immobile. However, experimental results from effects of Eh/pH revealed that In was slightly mobile under acidic (pH 4.5) in Eh range of 210-260 mV, and immobile under alkaline conditions (9.0) in Eh range of -250 to 125 mV. The release of Mo was slightly mobile under acidic conditions. However, Mo was very mobile under alkaline conditions and it increased with decreasing Eh. The release of Sr was significant under acidic conditions; however, it was immobile under alkaline conditions. Solubility and adsorption as affected by pH, and speciation could explain their release behaviors. Discrepancy in predictions from sequential extraction and actual observation from Eh/pH experiments was discussed.

Oxidative stress in blood and testicle of rat following intraperitoneal administration of aluminum and indium

Aluminum (Al) and indium (In) have embryotoxic, neurotoxic and genotoxic effects, oxidative stress being one of the possible mechanisms involved in their cytotoxicity. We have recently demonstrated that indium intraperitoneal (ip) administration induced histological disorganization of testicular tissue. In the present research we aimed at investigating the effect of Al and In ip administration on systemic and testicular oxidative stress status. Studies were performed on Wistar rats ip injected with Al, In or physiological solution for two weeks. Our results showed that In significantly decreased the absolute weight of testicles. Measurements of lactate dehydrogenase (LDH) and paraoxonase (PON) activities showed that In induced a significant augmentation in the first parameter but no changes were observed in the second. Both Al and In caused oxidative stress in testicles by increasing malondialdehyde (MDA) and protein carbonyls (PC) production. Concomitantly, thiol group (-SH) and glutathione (GSH) level were enhanced in the testicles. In the blood, while concentrations of MDA was not changed, those of GSH was significantly decreased in the Al and In groups. Our results indicated that Al and In cause oxidative stress both in blood and testicles but In has cytotoxic effect as well as negative impact on testicle weights. These findings could explain the testicular histological alterations previously described after In ip administration.

The impact of DNA methylation technologies on drug toxicology

INTRODUCTION

Drug toxicology is central to drug development. Despite improvements in our understanding of molecular and cell biology, high attrition rates in drug development continue, speaking to the difficulties of developing unequivocal methods to predict the efficacy and safety of drugs.

AREAS COVERED

In this review, the authors provide a short overview of the 'omics' technologies that have been applied to drug toxicology, with an emphasis on a whole-genome DNA methylation analysis. Preliminary results from DNA methylation analysis technologies that may help in predicting response and efficacy of a drug are discussed.

EXPERT OPINION

Currently, we cannot fully contextualize the application of epigenetics to the field of drug toxicology, as there are still many challenges to overcome before DNA methylation-based biomarkers can be effectively used in drug development. Comprehensive whole-genome DNA methylation methods for a unbiased analysis based on either microarray or next-generation sequencing need to be evaluated in drug toxicology in an intensive and systematic manner. Additionally, robust analysis systems need to be developed to decode the large amounts of data generated by whole-genome DNA methylation analyses as well as protocol standardization for reproducibility to develop meaningful databases that can be applied to drug toxicology.

Microscopy and microanalysis study of the indium (In) behavior in the intestinal mucosa, the liver, the kidney and the testicle

Several studies have demonstrated that In used in medicine has several impacts on organs like spleen and lungs after its systemic administration. In the present study, ultrastructural and microanalytical methods were used to investigate the impact of the presence of this element in the intestinal mucosa, the liver, the kidney and the testicle after its administration in two ways. After intraperitoneal administration, In was selectively concentrated in the lysosomes of hepatocytes, of tubular proximal convoluted cells and of Sertoli and Leydig cells. After intragastric administration, ultrastructural study showed that this element was concentrated in the lysosomes of duodenal enterocytes. Microanalytical methods showed that In was precipitated in those organelles in the form of insoluble phosphate salts. Similarly to other studies, it seemed that since In is a foreign element for the organism, it was precipitated in lysosomes, very probably due to the activity of an intralysosomal enzyme the acid phosphatase, to avoid its invasion to organism via the blood. This mechanism of precipitation of the mineral elements is of great interest in the process of defensive reaction of the organism against intoxication by foreign elements.