Effect of taurine on toxicity of aluminum in rats

Early Metabolomic Markers of Acute Low-Dose Exposure to Uranium in Rats

Changes in metabolomics over time were studied in rats to identify early biomarkers and highlight the main metabolic pathways that are significantly altered in the period immediately following acute low-dose uranium exposure. A dose response relationship study was established from urine and plasma samples collected periodically over 9 months after the exposure of young adult male rats to uranyl nitrate. LC-MS and biostatistical analysis were used to identify early discriminant metabolites. As expected, low doses of uranium lead to time-based non-toxic biological effects, which can be used to identify early and delayed markers of exposure in both urine and plasma samples. A combination of surrogate markers for uranium exposure was validated from the most discriminant early markers for making effective predictions. N-methyl-nicotinamide, kynurenic acid, serotonin, tryptophan, tryptamine, and indole acetic acid associated with the nicotinate–nicotinamide and tryptophan pathway seem to be one of the main biological targets, as shown previously for chronic contaminations and completed, among others, by betaine metabolism. This study can be considered as a proof of concept for the relevance of metabolomics in the field of low-dose internal contamination by uranium, for the development of predictive diagnostic tests usable for radiotoxicological monitoring.

Salinity-dependent effects of ZnO nanoparticles on bioenergetics and intermediate metabolite homeostasis in a euryhaline marine bivalve, Mytilus edulis

Engineered nanoparticles including ZnO nanoparticles (nZnO) are important emerging pollutants in aquatic ecosystems creating potential risks to coastal ecosystems and associated biota. The toxicity of nanoparticles and its interaction with the important environmental stressors (such as salinity variation) are not well understood in coastal organisms and require further investigation. Here, we examined the interactive effects of 100 μg l^-1 nZnO or dissolved Zn (as a positive control for Zn²⁺ release) and salinity (normal 15, low 5, and fluctuating 5-15) on bioenergetics and intermediate metabolite homeostasis of a keystone marine bivalve, the blue mussel Mytilus edulis from the Baltic Sea. nZnO exposures did not lead to strong disturbances in energy or intermediate metabolite homeostasis regardless of the salinity regime. Dissolved Zn exposures suppressed the mitochondrial ATP synthesis capacity and coupling as well as anaerobic metabolism and modified the free amino acid profiles in the mussels indicating that dissolved Zn is metabolically more damaging than nZnO. The environmental salinity regime strongly affected metabolic homeostasis and altered physiological and biochemical responses to nZnO or dissolved Zn in the mussels. Exposure to low (5) or fluctuating (5-15) salinity affected the physiological condition, energy metabolism and homeostasis, as well as amino acid metabolism in M. edulis. Generally, fluctuating salinity (5-15) appeared bioenergetically less stressful than constantly hypoosmotic stress (salinity 5) in M. edulis indicating that even short (24 h) periods of recovery might be sufficient to restore the metabolic homeostasis in this euryhaline species. Notably, the biological effects of nZnO and dissolved Zn became progressively less detectable as the salinity stress increased. These findings demonstrate that habitat salinity must be considered in the biomarker-based assessment of the toxic effects of nanopollutants on coastal organisms.

A Novel Approach towards Synthesis and Characterization of Non-Cytotoxic Gold Nanoparticles Using Taurine as Capping Agent

Metal gold nanoparticles are of great interest due to their unique physico-chemical properties and their potential to be used as nano-probes in biosensors, drug delivery, and therapeutic applications. Currently, many capping agents are used for metal gold nanoparticles, such as cetyltrimethylammonium bromide (CTAB) and tri-sodium citrate that have been reported to be toxic and hinders biological applications. To address this issue, we report, for the first time, the use of taurine as a stable non-cytotoxic capping agent for synthesizing gold nanoparticles by using an in situ wet-chemical method. This facile method resulted in monodisperse gold nanospheres with a high yield and stability. Monodisperse gold nanospheres with average diameters of 6.9 nm and 46 nm were synthesized at a high yield with controlled morphology. Temperature played a critical role in determining the size of the taurine-capped gold nanoparticles. The subtle changes in the reaction parameters had a tremendous effect on the final size of nanoparticles and their stability. The synthesized nanoparticles were characterized by using optical spectroscopy, a ZetaSizer, a NanoSight, Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), X-ray Photon Spectroscopy (XPS) and Electron Microscopy to understand their physico-chemical properties. Taurine was explored as a capping and stabilizing agent for gold nanospheres, which were evaluated for their toxicity responses towards human liver carcinoma cells (HepG2) via MTT assay.

Expression of metallothioneins I and II related to oxidative stress in the liver of aluminium-treated rats

Hepatotoxicity, induced by aluminium chloride (AlCl₃), has been well studied but there are no reports about liver metallothionein (MT) genes induction. Therefore, it is of interest to establish the mechanism involving the relation between MT gene expression levels and the oxidative stress status in hepatic cells of aluminium-treated rats. Aluminium (Al) was administered to rats in their drinking water at a dose of 50 mg/kg body weight for three weeks. AlCl₃ provoked hepatotoxicity objectified by an increase in malondialdehyde (MDA), hydrogen peroxide (H₂O₂), advanced oxidation protein products (AOPP), protein carbonyls (PCO) and a decrease in reduced glutathione (GSH), non-protein thiols (NPSH) and vitamin C. CAT and Glutathione peroxidase (GPx) activities were decreased while Mn-SOD gene expression, total Metallothionein content and MT I and MT II genes induction were increased. There are changes in plasma of some trace elements, albumin levels, transaminases, LDH and ALP activities. All these changes were supported by histopathological observations.

Determination of aluminium induced metabolic changes in mice liver: a Fourier transform infrared spectroscopy study

In this study, we made a new approach to evaluate aluminium induced metabolic changes in liver tissue of mice using Fourier transform infrared spectroscopy analysis taking one step further in correlation with strong biochemical evidence. This finding reveals the alterations on the major biochemical constituents, such as lipids, proteins, nucleic acids and glycogen of the liver tissues of mice. The peak area value of amide A significantly decrease from 288.278±3.121 to 189.872±2.012 between control and aluminium treated liver tissue respectively. Amide I and amide II peak area value also decrease from 40.749±2.052 to 21.170±1.311 and 13.167±1.441 to 8.953±0.548 in aluminium treated liver tissue respectively. This result suggests an alteration in the protein profile. The absence of olefinicCH stretching band and CO stretching of triglycerides in aluminium treated liver suggests an altered lipid levels due to aluminium exposure. Significant shift in the peak position of glycogen may be the interruption of aluminium in the calcium metabolism and the reduced level of calcium. The overall findings exhibit that the liver metabolic program is altered through increasing the structural modification in proteins, triglycerides and quantitative alteration in proteins, lipids, and glycogen. All the above mentioned modifications were protected in desferrioxamine treated mice. Histopathological results also revealed impairment of aluminium induced alterations in liver tissue. The results of the FTIR study were found to be in agreement with biochemical studies and which demonstrate FTIR can be used successfully to indicate the molecular level changes.

Fenugreek seeds, a hepatoprotector forage crop against chronic AlCl3 toxicity

Background

Having considered how bioavailable aluminium (Al) may affect ecological systems and animals living there, especially cattle, and in search for a preventive dietary treatment against Al toxicity, we aimed to test the protective role of fenugreek seeds against chronic liver injury induced by aluminum chloride (AlCl₃) in Wistar rats.

Results

Five months of AlCl₃ oral exposure (500 mg/kg bw i.g for one month then 1600 ppm via drinking water) caused liver atrophy, an inhibition of aspartate transaminase (AST), alanine transaminase (ALT) and glutamyl transpeptidase (GGT), an enhancement of both lipid peroxidation and lactate dehydrogenase (LDH) activity and an increase of total protein level in liver. Moreover, histopathological and histochemical examinations revealed moderate alterations in the hepatic parenchyma in addition to a disrupted iron metabolism. Co-administration of fenugreek seed powder (FSP) at 5% in pellet diet during two months succeeded to antagonize the harmful effects of AlCl₃ by restoring all tested parameters.

Conclusion

This study highlighted the hepatotoxicity of AlCl₃ through biochemical and histological parameters in one hand and the hepatoprotective role of fenugreek seeds on the other hand. Thus this work could be a pilot study which will encourage farmers to use fenugreek seeds as a detoxifying diet supplement for domestic animals.