Effects of Subchronic Aluminum Exposure on the Reproductive Function in Female Rats

The aim of this study was to investigate the effects of aluminum (Al) exposure on the reproductive function in female rats. Forty female Wistar (5 weeks old) rats, weighing 110–120 g, were divided randomly into four groups. They were orally administrated with 0, 64.18, 128.36, and 256.72 mg aluminum chloride (AlCl₃) per kilogram body weight in drinking water for 120 days. Levels of Al, estrogen (E₂), progestogen (P), testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in serum were measured at the end of experiment. The results showed that levels of E₂, P, FSH, and LH were significantly lower and Al concentration was significantly higher in all three Al-treated groups than those in the control group (GC). The level of T was significantly higher in the low- and medium-dose groups (GL and GM) (P < 0.05) but not in high-dose group (GH) compared with GC. The results suggest that the reproductive function of female rats is inhibited under long-term Al exposure in an Al dose-dependent manner.     

Effects of Subchronic Aluminum Exposure on the Immune Function of Erythrocytes in Rats

This study assessed effects of aluminum (Al) exposure on the immune function of erythrocytes in rats. Forty male Wistar rats (5 weeks old) weighed 110–120 g were randomly allocated equally into four groups according to their weights and were orally exposed to 0, 64.18, 128.36, and 256.72 mg/kg body weight aluminum trichloride in drinking water for 120 days. Levels of erythrocytes C_3b receptor rate (RBC-C_3bRR), erythrocytes C_3b immune complex rosette rate (RBC-ICR), erythrocytes rosette forming enhancing rate (ERER) and erythrocytes rosette forming inhibitory rate (ERIR) were determined by the end of experiment. The three Al-treated groups had lower values of RBC-C_3bRR and ERER, and higher values of RBC-ICR and ERIR than those in control group. The levels of RBC-C_3bRR and ERER decreased, while the levels of RBC-ICR and ERIR increased with the increases of Al content in drinking water. The results suggest that the immune function of erythrocytes in rats is suppressed by Al exposure.     

旋转恒定磁场对大鼠血清中铁代谢相关蛋白的影响

目的:观察旋转恒定磁场对大鼠血清中铁代谢相关蛋白的影响,为深入认识磁场的多方面生物学效应提供依据.方法:将SD大鼠随机分为对照组和曝磁组.后者在磁场强度是0.4 T、频率为8.97 Hz的环境中每天曝磁1次,每次2 h,连续处理30 d后处死分组大鼠,获得血清,冻存后测定血清中铜蓝蛋白活力和总抗氧化能力、铁蛋白和乳铁蛋白含量等指标.结果:曝磁组大鼠血清中铜蓝蛋白活力与对照组大鼠相比没有显著性变化;总抗氧化能力有了显著性的提高(P＜0.05);铁蛋白含量有显著性的降低(P＜0.05);乳铁蛋白含量有显著性的降低(P＜0.01).结论:磁场对大鼠血清中铁代谢的部分相关蛋白存在影响.     

Effects of Aluminum Exposure on Serum Sex Hormones and Androgen Receptor Expression in Male Rats

The effects of aluminum (Al) exposure on reproductive functions of male rats were investigated. Forty male Wistar rats (4?weeks old) weighing 75-95?g were randomly divided into four groups and orally exposed to 0 (control group GC), 64.18 (low-dose group GL), 128.36 (middle-dose group GM), and 256.72 (high-dose group GH) mg/kg aluminum trichloride in drinking water for 120?days. The levels of testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were determined by radioimmunoassay. The androgen receptor (AR) expressions in testes were detected respectively by immunohistochemistry and time quantitative PCR. Results showed that the levels of T and LH in GM and GH were lower than those in GC (P??0.05). AR protein expressions in GM and GH were lower than those in GC (P?相似文献   

Effects of Aluminum Exposure on Bone Mineral Density,Mineral, and Trace Elements in Rats

The purpose of the study was to investigate the effects of aluminum (Al) exposure on bone mineral elements, trace elements, and bone mineral density (BMD) in rats. One hundred Wistar rats were divided randomly into two groups. Experimental rats were given drinking water containing aluminum chloride (AlCl₃, 430 mg Al³⁺/L), whereas control rats were given distilled water for up to 150 days. Ten rats were sacrificed in each group every 30 days. The levels of Al, calcium (Ca), phosphorus (P), magnesium (Mg), zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), selenium (Se), boron (B), and strontium (Sr) in bone and the BMD of femur were measured. Al-treated rats showed lower deposition of Ca, P, and Mg compared with control rats. Levels of trace elements (Zn, Fe, Cu, Mn, Se, B, and Sr) were significantly lower in the Al-treated group than in the control group from day 60, and the BMD of the femur metaphysis in the Al-treated group was significantly lower than in the control group on days 120 and 150. These findings indicate that long-term Al exposure reduces the levels of mineral and trace elements in bone. As a result, bone loss was induced (particularly in cancellous bone).     

Effect of Aluminum Exposure on Glucose Metabolism and Its Mechanism in Rats

The transforming growth factors β1 (TGF-β1) and TGF-β2, as two distinct homodimers of TGF-β superfamily, involve in chondrocyte growth and differentiation. Emerging evidence has implied that strontium (Sr) plays an important role in the bone formation and resorption, and has strong effects on stimulating human cartilage matrix formation in vitro. However, the direct effects of Sr on TGF-β1 and TGF-β2 expressions in chondrocytes are not entirely clear. The purpose of this study was to evaluate the influence of different Sr concentrations on the expression of TGF-β1 and TGF-β2 in rat chondrocytes in vitro. Chondrocytes were isolated from Wistar rat articular by enzymatic digestion. Strontium chloride hexahydrate (SrCl₂·6H₂O) was used as a Sr source in this study. Sr was added to the culture solution at final concentrations of 0, 0.5, 1.0, 2.0, 5.0, 20.0, and 100 μg/mL. After 72 h of continuous culture, TGF-β1 and TGF-β2 mRNA abundance and protein expression levels in the chondrocytes were determined by real-time polymerase chain reaction (real-time PCR) and Western blot, respectively. The results showed that TGF-β1 and TGF-β2 expressions in chondrocytes increased dose-dependently with Sr concentration. The mRNA abundance of TGF-β1 and TGF-β2 were markedly higher than those observed for control (P?<?0.01) when the Sr-treated concentration exceeded 1.0 and 5.0 μg/mL, respectively. The TGF-β1 and TGF-β2 protein expression levels were extremely significantly higher than those in the control group (P?<?0.01) at above 5.0 μg/mL Sr-treatment. These results indicated that Sr could involve in the chondrocytes metabolism via regulating TGF-β1 and TGF-β2 signalling.     

Effects of Subchronic Administration of Metrifonate on Cholinergic Neurotransmission in Rats

The effects of subchronic oral administration of metrifonate, a long-acting cholinesterase (ChE) inhibitor, on cholinergic neurotransmission were assessed in young adult male Wistar rats. Animals were treated twice daily with metrifonate. In a pilot study testing a 100 mg/kg dose of metrifonate for up to 14 days, ChE activity was found to steadily decrease to reach maximum inhibition levels of about 55%, 80% and 35% in brain, erythrocytes and plasma. Steady-state inhibition levels were attained by the 10th day of treatment. When metrifonate-treatment was discontinued, ChE activity in plasma returned to control levels within another day, while erythrocyte and brain ChE activity took more than 2 weeks to recover. In subsequent dose-response studies, metrifonate treatment was given for 3 and 4.5 weeks at doses of 0, 12.5, 25, 50, and 100 mg/kg, to different groups of animals, respectively. Correlation analysis indicted that brain ChE inhibition was more accurately reflected by erythrocyte than by plasma ChE inhibition, although all effects were highly correlated. The changes in ChE activity were not paralleled by changes in other parameters of the cholinergic neurotransmission, such as acetylcholine synthesis rate or acetylcholine receptor binding. It is therefore concluded that repeated administration of metrifonate to rats induces a long-lasting inhibition of ChE activity in a dose-related and predictable manner, which is neither subject to desensitization nor paralleled by counterregulatory downregulation of muscarinic or nicotinic receptor binding sites in brain.     

Protective Effects of Mangiferin in Subchronic Developmental Lead-Exposed Rats

Lead is a ubiquitous environmental and industrial pollutant. Exposure to excessive amounts of lead is especially harmful to the central nervous systems of infants and young children, and oxidative stress has been reported as a major mechanism of lead-induced toxicity. To evaluate the ameliorative potential of antioxidant mangiferin (MGN) on lead-induced toxicity, Morris water maze test, determination of blood and bone lead concentration, determination of antioxidant status in plasma, as well as observation of ultrastructural changes in the hippocampus were carried out. In the present study, under a transmission electron microscope, ameliorated morphological damages in the hippocampus were observed in MGN-treated groups. Blood and bone lead concentration in MGN-treated groups lowered to some extent (p?<?0.05, p?<?0.01). The activities of antioxidant enzymes, glutathione (GSH) content, and the GSH/oxidized glutathione ratio in MGN-treated groups were increased, respectively. Further studies are needed to establish whether the observed differences were a direct cause of mangiferin on lead-induced toxicity or not. This study might provide clues for the treatment of lead-induced toxicity.     

The Effects of Physical Exercise on the Serum Iron Profile in Spontaneously Hypertensive Rats

The purpose of this study was to evaluate the profile of serum iron in spontaneously hypertensive rats after an aerobic physical exercise. To accomplish this, 12 normotensive Wistar rats and 12 spontaneously hypertensive rats were distributed into “physical exercise” and “no physical exercise” groups. The animals in the physical exercise group underwent to an aerobic exercise for a total of 4 weeks. Blood was collected for the analysis of iron. Our results indicate that rats of the physical exercise group had significantly lower serum iron levels after the aerobic exercise protocol compared to the spontaneously hypertensive rats no physical exercise group (F _(3,16) = 4.4915, p < 0.01). No significant difference was found between no physical exercise groups. The results indicated that the difference in iron may be due to an increased demand for iron, prompted by chronic physical exercise. In addition, erythrocytosis has been associated with increased blood pressure in spontaneously hypertensive rats, suggesting that iron reduction may be related to decreased blood pressure in these animals.     

Effects of Formaldehyde Inhalation on Zinc,Copper and Iron Concentrations in Liver and Kidney of Male Rats

In the present study, adult Wistar albino male rats were exposed to formaldehyde at different periods (subacute and subchronic) and concentrations (5.0 and 10.0 ppm) in order to figure out the changes in the concentration of Zn, Cu and Fe. It was observed that the formaldehyde inhalation caused gradual decline of body weights in the experimental groups when compared with control groups. It was found that subacute (4-week) or subchronic (13-week) exposure to formaldehyde for rats may cause growth retardation. After inhalation procedure, concentration of copper, zinc and iron were determined in liver and kidney tissues of rats using atomic absorption spectrophotometer. In addition, concentrations of Cu, Zn and Fe changed by the effect of formaldehyde in subacute and subchronic groups.     

Subchronic Arsenic Exposure Through Drinking Water Alters Lipid Profile and Electrolyte Status in Rats

Arsenic is a groundwater pollutant and can cause various cardiovascular disorders in the exposed population. The aim of the present study was to assess whether subchronic arsenic exposure through drinking water can induce vascular dysfunction associated with alteration in plasma electrolytes and lipid profile. Rats were exposed to arsenic as 25, 50, and 100 ppm of sodium arsenite through drinking water for 90 consecutive days. On the 91st day, rats were sacrificed and blood was collected. Lipid profile and the levels of electrolytes (sodium, potassium, and chloride) were assessed in plasma. Arsenic reduced high-density lipoprotein cholesterol (HDL-C) and HDL-C/LDL-C ratio, but increased the levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and electrolytes. The results suggest that the arsenic-mediated dyslipidemia and electrolyte retention could be important mechanisms in the arsenic-induced vascular disorder.     

Effects of Aluminum Exposure on the Adherence, Chemotaxis, and Phagocytosis Capacity of Peritoneal Macrophages in Rats

To investigate the effects of aluminum (Al) exposure on peritoneal macrophages of Wistar rats, four groups of ten rats each were orally exposed to 0, 13, 26, and 52?mg?kg(-1) Al(3+) in form of aluminum trichloride (AlCl(3)) in drinking water for 120?days. At the end of the experimental period, the Al concentration in serum, the adherence, chemotaxis, and phagocytosis capacity of peritoneal macrophages were determined. The results showed that the Al concentration in serum significantly increased in a dose-dependent manner; the adherence, chemotaxis, and phagocytosis capacity of peritoneal macrophages decreased with the increase of Al dose, and present a dose-effective relationship. Further, they were significantly lower in the high-dose groups (P?相似文献   

Hematotoxicity and Genotoxicity of Mercuric Chloride Following Subchronic Exposure Through Drinking Water in Male Rats

Erythrocytes are a convenient model to understand the subsequent oxidative deterioration of biological macromolecules in metal toxicities. The present study examined the variation of hematoxic and genotoxic parameters following subchronic exposure of mercuric chloride via drinking water and their possible association with oxidative stress. Male rats were exposed to 50 ppm (HG1) and 100 ppm (HG2) of mercuric chloride daily for 90 days. A significant dose-dependent decrease was observed in red blood cell count, hemoglobin, hematocrit, and mean cell hemoglobin concentration in treated groups (HG1 and HG2) compared with controls. A significant dose-dependent increase was observed in lipid peroxidation; therefore, a significant variation was found in the antioxidant enzyme activities, such as superoxide dismutase, catalase, and glutathione peroxidase. Interestingly, mercuric chloride treatment showed a significant dose-dependent increase in frequency of total chromosomal aberration and in percentage of aberrant bone marrow metaphase of treated groups (p < 0.01). The oxidative stress induced by mercury treatment may be the major cause for chromosomal aberration as free radicals lead to DNA damage. These data will be useful in screening the antioxidant activities of natural products, which may be specific to the bone marrow tissue.     

Melatonin Ameliorates Neuropharmacological and Neurobiochemical Alterations Induced by Subchronic Exposure to Arsenic in Wistar Rats

Biological Trace Element Research - An experimental study was conducted in Wistar rats to characterize the arsenic (“As”)-induced alterations in neurobiochemistry in brain and its...     

Monitoring Gas Concentrations in Pollutant Exposure Systems: Defining Exposure Concentrations

Several reasons have been offered in the recent literature toexplain the disagreement in experimental results on the effectsof SO² on plants. The tacit assumption that each research groupis monitoring exposure concentration in a comparable manneris challenged. For example, in well-stirred chambers exposureconcentrations are identical with outlet concentrations, yetseveral studies have interpreted plant response in terms ofsupply (i.e. inlet) concentrations. Experiments are presentedthat illustrate the extent to which supply concentrations canbe depleted within chambers, and the magnitude of error in assumingsupply to represent exposure concentrations. Definitions forexposure concentration in chamber, wind tunnel, and glasshousesystems are suggested.     

Effects of Low Doses of Fluoride on Serum Proteins and a Serum Enzyme in Man

FLUORIDE ions have long been known to exert an inhibitory effect on the activity of certain enzymes-Frajola¹ lists ten human enzymes which are definitely inhibited in vitro and suggests that there may be more. In an experiment in one subject receiving 36 mg of sodium fluoride daily for 18 days Frajola was able to show that the activities of the serum enzymes lactic dehydrogenase, acid phosphatase and glutamic transaminase were reduced, but he does not say whether the general health of the subject was affected. Opponents of fluoridation as a public health measure argue that the action as an enzyme inhibitor will affect general health and they quote instances of subjectively assessed ill-health and allergylike reactions following fluoridation of public water supplies, but careful medical observations in fluoridated areas have shown no increase of systemic disease and no significant variation in mortality rates. It has been stated² that there is no evidence that fluoride ingested at 1 p.p.m. in drinking water has any effect on human enzyme activity, but there are no specific experimental data on this question.     

Prenatal Amphetamine Exposure Effects on Dopaminergic Receptors and Transporter in Postnatal Rats

We investigated the influence of prenatal amphetamine exposure (PAE) on dopamine (DA) receptors, and dopamine transporter (DAT) in various striatal and limbic subregions and locomotor activity induced by novel environmental conditions and amphetamine at two postnatal ages, 35 days old (prepubertal) and 60 days old (postpubertal). Experiments were carried out on pregnant female Sprague–Dawley rats, which were daily injected with either d-amphetamine sulfate (1 mg/kg) or saline solution (0.9%) for 11 days, from gestation day 11–21. In PAE rats compared to control we found the following: at pre-pubertal age, an enhancement of DA D1 in the dorsolateral area of the caudate-putamen (CPu), CPu-ventral and shell of the nucleus accumbens (NAcc) with a decrement of the DA D3 receptors in NAcc, olfactory tubercle (OT), and the islands of Calleja (IoC); whereas at postpubertal age, an increase in the levels of DAT in the NAcc and fundus of the CPu, and OT along with a decrease in the expression of DA D2 receptors only in the NAcc shell were found in PAE rats compared to control. In addition, amphetamine induces a marked decrease in locomotor activity at postpubertal age in rats with PAE. These results suggest a differential effect of amphetamines on the DAT mechanism of the nervous system during embryonic development of animals with implications in behavior and drug addictions at adulthood age.     

The Effects of Whole Body Cell Phone Exposure on the T1 Relaxation Times and Trace Elements in the Serum of Rats

The objective of this study was to investigate the effects of radiofrequency radiation emitted from cellular phones on: (1) trace elements such as manganese, iron, copper, zinc, (2) T1 relaxation times in serum, and (3) rectal temperature of rats exposed to microwave radiation emitted from cellular phones. Sixteen Spraque–Dawley rats were separated into two groups of eight, one sham-exposed (control) and one exposed (experimental). The rats were confined in Plexiglas cages and a cellular phone was placed 0.5 cm under the cage. For the experimental group, cellular phones were activated 20 min per day, 7 days a week, for 1 month. For the control group, a cellular phone placed beneath the cage for 20 min a day was turned off. Rectal temperatures were measured weekly. For 250-mW-radiated powers, the whole body average specified absorption rate (SAR) (rms) is 0.52 W/kg and 1-g-averaged peak SAR (rms) is 3.13 W/kg. The Mann-Whitney U test was used for statistical comparisons of groups. T1 relaxation time and the values of iron and copper in the serum of the experimental group were not changed compared to the control group (p > 0.05). However, manganese and zinc values in the serum of the experimental group were significantly different from the control group (p < 0.05). The difference in rectal temperature measured before and after exposure in the experimental groups was not statistically different from control (p > 0.05).