Effect of cadmium on lipid composition of the weanling rat brain

Effects of endocrine disrupting chemicals on myelin development and diseases

In the central and peripheral nervous systems, myelin is essential for efficient conduction of action potentials. During development, oligodendrocytes and Schwann cells differentiate and ensure axon myelination, and disruption of these processes can contribute to neurodevelopmental disorders. In adults, demyelination can lead to important disabilities, and recovery capacities by remyelination often decrease with disease progression. Among environmental chemical pollutants, endocrine disrupting chemicals (EDCs) are of major concern for human health and are notably suspected to participate in neurodevelopmental and neurodegenerative diseases. In this review, we have combined the current knowledge on EDCs impacts on myelin including several persistent organic pollutants, bisphenol A, triclosan, heavy metals, pesticides, and nicotine. Besides, we presented several other endocrine modulators, including pharmaceuticals and the phytoestrogen genistein, some of which are candidates for treating demyelinating conditions but could also be deleterious as contaminants. The direct impacts of EDCs on myelinating cells were considered as well as their indirect consequences on myelin, particularly on immune mechanisms associated with demyelinating conditions. More studies are needed to describe the effects of these compounds and to further understand the underlying mechanisms in relation to the potential for endocrine disruption.

Gene expression profile of mouse fibroblasts exposed to a biodegradable iron alloy for stents

Iron-based materials could constitute an interesting option for cardiovascular biodegradable stent applications due to their superior ductility compared to their counterparts - magnesium alloys. Since the predicted degradation rate of pure iron is considered slow, manganese (35% w/w), an alloying element for iron, was explored to counteract this problem through the powder metallurgy process (Fe-35 Mn). However, manganese presents a high cytotoxic potential; thus its effect on cells must first be established. Here, we established the gene expression profile of mouse 3T3 fibroblasts exposed to Fe-35 Mn degradation products in order to better understand cell response to potentially cytotoxic degradable metallic material (DMM). Mouse 3T3 cells were exposed to degradation products eluting through tissue culture insert filter (3 μm pore size) containing cytostatic amounts of 3.25 mg ml(-1) of Fe-35 Mn powder, 0.25 mg ml(-1) of pure Mn powder or 5 mg ml(-1) of pure iron powder for 24 h. We then conducted a gene expression profiling study from these cells. Exposure of 3T3 cells to Fe-35 Mn was associated with the up-regulation of 75 genes and down-regulation of 59 genes, while 126 were up-regulated and 76 down-regulated genes in the presence of manganese. No genes were found regulated for the iron powder. When comparing the GEP of 3T3 fibroblasts in the presence of Fe-35 Mn and Mn, 68 up-regulated and 54 down-regulated genes were common. These results were confirmed by quantitative RT-PCR for a subset of these genes. This GEP study could provide clues about the mechanism behind degradation products effects on cells of the Fe-35 Mn alloy and may help in the appraisal of its potential for DMM applications.

Determination of acute and chronic effects of cadmium on the cardiovascular system of rats

In this study, the systemic hemodynamics induced by acute and chronic cadmium (Cd+2) intoxication in the cardiovascular system of rats using thoracic electrical bioimpedance were examined and the acute and chronic effects of Cd+2 intoxication on the activities of antioxidant enzymes and malondialdehyde (MDA) were compared. Also, in this study, ultrastructural changes in the heart and aorta of rats were evaluated. Thirty-eight male Wistar albino rats were randomly divided into control, acute, and chronic groups. Chronic group was administered by oral gavage an aqueous solution of CdCl2 for 60 days, at dose of 15 mg Cd+2/kg/day. Acute group was administered by oral gavage an aqueous solution of CdCl2 with a single dose of 15 mg Cd+2/kg. Cadmium increased the stroke volume and cardiac output of rats in the chronic group, but did not change the heart rate significantly. Antioxidant enzymes activities and MDA level significantly increased in the chronic group. In ultrastructural examination, there were widespread degenerative changes in heart muscle cells of the chronic group but endothelial cells and smooth muscle cells in the aorta tissue samples had normal morphological features in all groups. All of the findings indicate that Cd+2 toxication can cause deformation in heart muscle cells due to an increase in free radicals and lipid peroxidation. Also, this study has confirmed that a long-term-Cd+2 exposure increased stroke volume (SV) and cardiac output (CO), but did not change the heart rate (HR).

High sucrose consumption potentiates the sub-acute cadmium effect on Na+/K+-ATPase but not on δ-aminolevulinate dehydratase in mice

High sucrose consumption and sub-acute cadmium effects on delta-ALA-D activity, Na+/K+ -ATPase activity, and lipid peroxidation were studied in different tissues of mice. Experimental groups were control, high sucrose (200 g/L), cadmium (5 mg/kg/day, subcutaneously, two consecutive doses in different days in each week, during 4 weeks), and sucrose plus cadmium. There was a significant increase in TBARS levels for spleen and liver in cadmium and sucrose plus cadmium groups. Testicular delta-ALA-D activity of cadmium and sucrose plus cadmium-treated animals was significantly inhibited, whereas the enzyme activity increased in blood (cadmium and sucrose plus cadmium groups) and spleen (sucrose plus cadmium group). Na+/K+ -ATPase activity was significantly decreased in brain and kidney of sucrose plus cadmium-treated animals. Our data indicate that sub-acute cadmium treatment inhibits significantly testicular delta-ALA-D activity, demonstrating the prevalent cadmium effect in vivo on reproductive systems. Furthermore, high sucrose consumption and sub-acute cadmium treatment have interactive effects on cerebral and renal Na+/K+ -ATPase, showing that a short-term intake of high quantity of sucrose can aggravate the toxicity of Cd2+.

Increased spontaneous motor activity in offspring after maternal cadmium exposure during lactation

Lactating rats were exposed to 0, 5 or 25ppm cadmium as cadmium chloride in the drinking water. A battery of neurobehavioural tests was applied to the male offspring after weaning at 5 weeks until 4 months of age. The mean cadmium levels in exposed pup kidneys ranged from 0.006 to 0.030mg/kg wet weight at weaning, with the corresponding maternal kidney cadmium levels ranging from 4 to 13mg/kg wet weight. Significantly increased activity during the initial 20min of the spontaneous motor activity test was observed in the highest-dose group compared to the control group. The activity outcome was significantly positively correlated with cadmium levels in the pup kidneys. No cadmium-related changes in performance were observed in the Morris water maze, the E-shaped maze or the elevated plus-maze. The results indicate that neurobehavioural effects during development may be a more sensitive parameter for Cd toxicity than renal dysfunction.

Fatty acid alterations in liver and milk of cadmium exposed rats and in brain of their suckling offspring

Fatty acid composition was studied in milk at day 14 and in liver at day 24 after parturition of lactating rats exposed to 0 ppm, 5 ppm or 25 ppm cadmium (Cd) via drinking water for 17 days during lactation, and in the brain of their offspring at day 19 after birth. In the liver phospholipid fraction, 22:5(n-3) was significantly higher, while in the triacylglycerol fraction 22:6(n-3)/20:5(n-3) ratio was significantly lower in the 25 ppm group compared to the controls. Significantly higher proportions of 16:0 and lower proportions of medium-chain fatty acids, 8:0-14:0, were observed in milk of dams in the 25 ppm group, indicating decreased enzymatic activity of thiotransferase II in the mammary gland. Slightly increased levels of 20:3(n-6) were observed in brains of pups in the 25 ppm group compared to control. The results indicate that Cd exposure influences fatty acid metabolism in lactating rats.

The effect of cadmium and experimental diabetes on EEG spectral data

Fifty-two healthy male Swiss albino rats, aged three months, were used in this study. They were divided into four groups: control (C), diabetic (D), cadmium (Cd) and diabetic + Cd (D + Cd). Diabetes was induced in the D and D + Cd groups by administration of alloxane (5 mg/100 g). After this treatment, the Cd and D + Cd groups were injected with CdCl2 i.p. (2 mg/kg/week). At the end of the two month experimental period, EEGs of the four groups were recorded and amplitude spectral analysis was computed by Fast Fourier Transform (FFT) algorithm. Significant amplitude (dB) increment was observed in 16-30 Hz of Cd group compared with C and D groups. Significant amplitude decrement was found in the 2-4 Hz frequency band of the D + Cd group compared with C, Cd and D groups.

The adaptation of mussels Crenomytilus grayanus to cadmium accumulation result in alterations in organization of microsomal enzyme-membrane complex (non-specific phosphatase)

The kinetic parameters (V(m), K(m) and slope) of membrane-bound microsomal non-specific phosphatase (NPase, with G6P as the substrate) from the digestive gland of unexposed and cadmium adapted (45 days for 100 µg Cd(2+)/l) mussels were investigated. In vivo and in vitro approaches were used. Adaptation of mussels (Crenomytilus grayanus) to cadmium resulted in a 1.6-fold increase in NPase activity. V(m) was increased by 1.6-fold, but K(m) was the same in terms of enzyme kinetics. This indicates that the total concentration of the enzymes in the digestive gland increased. Cd(2+) (1 mM) did not significantly alter the activity of the membrane-bound enzyme in vitro both for unexposed and for cadmium adapted mussels, meaning that cadmium ions are not a direct inhibitor of the membrane-bound enzyme in this concentration. The microsomal NPase activity in both unexposed and cadmium adapted mussels was inhibited by in vitro solubilization of microsomes with non-ionic detergent (Triton X100, 0.01%). This inhibition was uncompetitive for microsomes of unexposed mussels (K(m) decreased 3.1-fold). The most drastic events were observed in cadmium adapted mussels, where inhibition was mixed (K(m) decreased 7.2-fold). The simultaneous actions of detergent and cadmium ions did not alter NPase activity significantly in comparison with action of the detergent alone. The differences in the types and the extents of inhibition of the enzymes activity by membrane disordering agent (Triton X100) indicated that the enzyme-membrane complex (NPase) has been altered as a result of adaptation of mussels to cadmium accumulation. We conclude that the mussels produced a new enzyme-membrane complex, with the same K(m) as the previous complex, but with other detergent sensitivity and greater amounts. Thus, the adaptation capacity of this enzyme is reduced as result of adaptation of mussels to cadmium accumulation.

The effect of pre and postnatal cadmium exposure on somatosensory evoked potentials: relation to lipid peroxidation

Pregnant swiss albino rats were divided into three groups: control (C), gestational exposure of cadmium (G-Cd) and gestational/postnatal exposure of cadmium (GP-Cd) groups. Control animals received tap water and the rats of GP-Cd group received Cd as CdCl2 in their drinking water during the experimental period. G-Cd group was given Cd during pregnancy, but given tap water after birth. Twenty-two days after birth, 15 rats (for each group) were taken from their mothers and continued to be treated with Cd (GP-Cd group) or tap water (C and G-Cd groups) for an additional 38 days. On postnatal day (PND) 60, somatosensory evoked potentials (SEPS) of three groups were recorded following left posterior tibial nerve (PTN) stimulation. The mean latencies of N1, P1, and N2, components were significantly prolonged in both Cd groups compared with control group. The mean latency of N1 in the GP-Cd group was longer than control and the G-Cd groups. There was no significant amplitude differences among groups. On the other hand, thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation, were increased in the sciatic nerves of both groups compared with control group. A significant increase in the TBARS level of the brain was found only in GP-Cd group due to significant accumulation of Cd.

The effect of cadmium (Cd) treatment on somatosensory evoked potentials (SEPs) and conduction velocity in alloxane-induced diabetic rats: relation to lipid peroxidation

Fifty-two healthy Swiss male albino rats, aged three months, were divided into four groups: Control (C), diabetic (D), cadmium (Cd), and diabetic + Cd (D+Cd). Diabetes was induced in D and D+Cd groups by administration of alloxane (5 mg/100 g). Cd and D+Cd groups were injected with CdCl2 i.p. (2 mg/kg/week) for 2 months. Somatosensory evoked potentials (SEPs) of the four groups were recorded following left posterior tibial nerve (PTN) stimulation. The mean latencies of P1, N1, P2 and N2 components were prolonged in all experimental groups compared with the control group. P1N1 and N1P2 amplitudes were significantly decreased in Cd and D+Cd groups in comparison with the control group. P2N2 amplitude was significantly decreased in the Cd group compared with the control group. In addition, conduction velocities and action potential amplitudes were determined from the sciatic nerves. The means of peripheral conduction velocities and action potential amplitudes were decreased significantly in all the experimental groups in comparison with the control group. Thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation, were increased in the kidneys and sciatic nerves of all experimental groups compared with the control group. A significant increase in the TBARS level of the brain was found in the Cd and D+Cd groups.

The effects of cadmium and experimental diabetes on VEP spectral data and lipid peroxidation

Fifty-two healthy swiss male albino rats, aged three months were used in this study. They were divided into four groups: Control (C), diabetic (D), Cadmium (Cd) and diabetic + Cadmium (D + Cd) groups. Diabetic condition was induced in D and D + Cd groups by administration of alloxane (5 mg/100 g). After this treatment, Cd and D + Cd groups were injected with CdCl2 i.p. (2 mg/kg/week). At the end of the two months of experimental period, flash visual evoked potentials (FVEPs) of four groups were recorded and amplitude spectral analysis was computed by transient response-frequency characteristics (TRFC) method. Significant amplitude decrement was found in 2-4 Hz frequency band of D + Cd group in comparison with C group. On the other hand, our data showed that Cd treatment and diabetic condition caused a significant increase of lipid peroxidation in kidney, brain, retina and lens.

Effect of cadmium on antioxidant status in alloxane-induced diabetic rats

Fifty-two healthy Swiss Male Albino rats aged two mo were used in this study. They were divided into four groups: control (C), diabetic (D), cadmium (Cd), and diabetic + Cd (D + Cd) groups. Diabetic condition was induced in D and D + Cd groups by administration of alloxane (5 mg/100 g). After this treatment, Cd and D + Cd groups were injected with CdCl2 i.p. (2 mg/kg/wk). At the end of the 2-mo experimental period, thiobarbituric acid reactive substances (TBARS), plasma and erythrocyte selenium (Se), plasma ceruloplasmin (Cp), and vitamin E (vit E) were determined in four groups of rats. The erythrocyte Se was lower in the experimental groups than in the controls. Plasma Se was significantly decreased in the D and D + Cd groups compared with the control group. Plasma Cp was unaltered. Plasma vit E was significantly decreased in Cd group in comparison with the C, D, and D+Cd groups.

Time-dependent cadmium-neurotoxicity in rat brain synaptosomal plasma membranes

1. The modulation of lipid dynamics and lipid protein interactions were studied in rat brain synaptosomal plasma membranes (SPM) up to 24 hr after exposure to cadmium (Cd). 2. The activity of acetylcholinesterase and adenylate cyclase showed a considerable decrease after 6 hr of Cd exposure, followed by a progressive increase up to 24 hr. 3. SPM chemiluminescence showed a maximum decrease at 12 hr, demonstrating a considerable increase in lipid peroxidation. 4. SPM of Cd-exposed animals showed a statistical significant increase in fluorescence anisotropy parameter [(r0/r) - 1]-1 at 18 and 24 hr compared to SPM of the control, indicating a decrease of membrane fluidity.

The effect of cadmium on the composition and metabolism of hepatic fatty acids in zinc-adequate and zinc-deficient rats

Exposure to cadmium (Cd) caused changes in the fatty acid composition of phospholipids, such as increases in levels of saturated and (n-6) fatty acids and decreases in levels of (n-9) fatty acids, in the liver phospholipids of rats fed a fat-free diet. These changes were similar to those caused by dietary zinc deficiency. The changes in fatty acid composition after administration of Cd were greater in zinc-deficient (ZD) rats than zinc-adequate (ZA) rats. When [14C]18:0 was injected intravenously in order to examine the metabolism of (n-9) fatty acids, a decrease in the rate of conversion of [14C]18:0 to [14C]18:1 was observed in liver phospholipids after treatment of ZD rats with Cd. These results suggested that Cd can affect the metabolism of fatty acids in relation to zinc status and, in particular, causes a reduction in the activity of delta 9-desaturase which converts 18:0 to 18:1.

Effect of cadmium on lipid peroxidation and antioxidant enzymes in undernourished weanling rat brain

The effect of early postnatal cadmium exposure on lipid peroxidation and antioxidant enzymes in undernourished weanling rat brain has been studied. The results suggest that undernutrition makes the weanling rat brain more susceptible to the neurotoxic effects of cadmium. Cadmium at a low dose of 1 mg/kg body weight did not produce any changes in lipid peroxidation and antioxidant enzymes in normal weanling rat brain, but caused a significant increase in lipid peroxidation and markedly decreased the activities of antioxidant enzymes like glutathione peroxidase, superoxide dismutase and catalase when subjected to undernutrition.

Effect of cadmium on lipid metabolism of brain: in vivo incorporation of labelled acetate into lipids

The effect of early postnatal cadmium exposure on the in vivo incorporation of (1-14C) sodium acetate into various lipid classes of the weanling rat brain was studied. A stimulated incorporation of the label was observed in total lipids, phospholipids, cholesterol, cerebrosides and sulphatides of the brain of Cd-exposed animals compared to controls.