Effects of Lead on Hepatic Antioxidant Status and Transcription of Superoxide Dismutase Gene in Pigs

Ninety-six castrated boars (Duroc x Landrace x Yorkshire) were randomly divided into four groups, each of which was replicated three times with eight pigs. The groups received the same basal diet supplemented with 0, 5, 10, and 20 mg/kg lead, respectively. The malondialdehyde and glutathione levels, antioxidant enzymes activities, and zinc/copper superoxide dismutase (Zn/Cu SOD) mRNA content in the liver were determined to evaluate the lead hepatic intoxication caused by the lead. Results showed the increased lipid peroxides level and the reduced glutathione content, along with a concomitant decrease in the activities of superoxide dismutase, catalase, and glutathione peroxidase. Moreover, the level of hepatic Zn/Cu SOD mRNA was also significantly reduced. We suggest potential mechanism for lead intoxication in liver as follows: lead causes parallel decrease in Zn/Cu SOD mRNA and activities of antioxidant enzymes, leading to the declined ability of scavenging free radicals with excessive production of lipid peroxides, which seriously damages the hepatic structure and function.     

Effect of diet on the response in rats to lead acetate given orally or in the drinking water

Liver lead levels were higher for rats that were orally dosed with 100 mg lead acetate/kg body wt and fed a semipurified diet than those fed a pelleted diet. The activities of delta-aminolevulinic acid dehydratase in blood were decreased in the group given 10 μg lead acetate/mL in their drinking water and fed the semipurified diet, but not in the blood from the group treated with lead and fed the pelleted diet. The levels of glutathione in the liver decreased in response to lead acetate in the drinking water of rats fed the semipurified diet, but not in the livers from the group fed the pelleted diet and treated with lead. The levels of lead in the kidneys were higher in the group given lead acetate in their drinking water and fed the semipurified diet than in the lead treated group fed the pelleted diet. Rats dosed orally with lead or given lead in the drinking water and fed the semipurified diet were more sensitive to lead treatment than those fed the pelleted diet.     

Antioxidant and hypolipidaemic properties of red seaweed,Gracilaria changii

The edible red seaweed, Gracilaria changii, was collected from the coastal area of Sarawak, Malaysia, and evaluated for its hypolipidaemic properties using high cholesterol/high fat (HF) induced male Sprague–Dawley rats. In the in vivo study, the HF diet group showed significantly higher total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), atherogenic index (AI) and body weight gain as compared to other treatment groups. At the end of treatment period, rats fed with a HF diet supplemented with 5 % freeze-dried G. changii powder had significantly reduced plasma TC (?39.19 %), LDL-C (?36.36 %), and triglycerides (TG) content (? 25.45 %). Meanwhile, 10 % seaweed powder significantly lowered the plasma TC, LDL-C and TG content by ?40.34, ?35.95 and ?30.91 % respectively, compared to the HF group. The AI of rats supplemented with 10 % seaweed powder was the lowest among the treatment groups and indicates a lowered risk for cardiovascular diseases. The plasma lipid peroxidation of the seaweed powder-fed groups was also significantly lower than the HF group, while the erythrocyte enzyme antioxidant activities of superoxide dismutase, catalase and glutathione peroxidase of the treatment groups were also improved. Diets supplemented with seaweed powder also decreased plasma aspartate aminotransferase and the alanine aminotransferase levels.     

Role of selenium against lead toxicity in male rats

Male albino rats were intramuscularly administered a single dose of lead acetate (100 μmol/kg b.wt). Another group of rats were injected with sodium selenite (10 μmol/kg b.wt) before lead intoxication. After 3 and 24 hours, lead treatment resulted in significant increases in acid and alkaline phosphatases, GOT and GPT, total proteins, and cholesterol in serum. The total triglycerides in serum was decreased after 24 hours of intoxication. Lead treatment also produced significant elevation of lipid peroxidation in liver and kidney. The antioxidant capacity of hepatic and renal cells in terms of the activities of superoxide dismutase, glutathione reductase, and glutathione content was diminished. It appears from these results that lead may exert its toxic effect via peroxidative damage to renal and hepatic cell membranes after 24 hours. Selenium administration prior to lead injection produced pronounced prophylactic action against lead effects, and it is observed that selenium enhances the endogenous antioxidant capacity of the cells by increasing the activities of the superoxide dismutase and glutathione reductase and the glutathione content. As a result, the lipid peroxidation was decreased in both liver and kidney. © 1998 John Wiley & Sons, Inc. J Biochem Mol Toxicol 12: 345–349, 1998     

The effects of dietary boric acid and borax supplementation on lipid peroxidation,antioxidant activity,and DNA damage in rats

The aims of this study were to clarify the effects of high dietary supplementation with boric acid and borax, called boron (B) compounds, on lipid peroxidation (LPO), antioxidant activity, some vitamin levels, and DNA damage in rats. Thirty Sprague Dawley male rats were divided into three equal groups: the animals in the first group (control) were fed with a standard rodent diet containing 6.4 mg B/kg, and the animals in the experimental group were fed with a standard rodent diet added with a supra-nutritional amount of boric acid and borax (100 mg B/kg) throughout the experimental period of 28 days. The B compounds decreased malondialdehyde (MDA), DNA damage, the protein carbonyl content (PCO) level in blood, and glutathione (GSH) concentration in the liver, Cu–Zn superoxide dismutase (SOD), and catalase (CAT) activity in the kidney. The B compounds increased GSH concentration in blood and the vitamin C level in plasma. Consequently, our results demonstrate that B supplementation (100 mg/kg) in diet decreases LPO, and enhances the antioxidant defense mechanism and vitamin status. There are no differences in oxidant/antioxidant balance and biochemical parameters except for serum vitamin A and liver GSH concentration, between the boron compounds used in this study.     

Chromium(III) Nanoparticles Affect Hormone and Immune Responses in Heat-Stressed Rats

This study was conducted to evaluate the effects of chromium nanoparticles (CrNano) on the hormone and immune responses of rats in heat stress condition. A total of 80 male Sprague–Dawley rats were randomly assigned to four dietary treatment groups (n?=?20). The first group was offered a basal diet as a control. The second, third, and fourth groups received basal diet supplemented with 150, 300, and 450 μg/kg Cr, respectively, in the form of CrNano. At the end of the 8-week trial, growth performance, food utilization, and sera concentrations of hormones, immunoglobulins, and alexins were determined. Lymphocyte proliferation activity, antibody response to injected sheep red blood cells (SRBCs), and phagocytosis of peritoneal macrophages were determined by ³H-thymidine uptake method, plaque-forming cells (PFC) assay, and ingesting chicken red blood cells test, respectively. The results indicated that rats that received CrNano exhibited no changes in growth rate and food efficiency compared to the control group. However, dietary supplementation of 150, 300, and 450 μg/kg Cr from CrNano significantly decreased serum concentrations of insulin and cortisol, increased sera levels of insulin-like growth factor I and immunoglobulin G, and enhanced the lymphoproliferative response, anti-SRBC PFC response, and phagocytic activity of peritoneal macrophages. These results suggest that dietary supplementation of Cr as CrNano affects hormone and immune status in heat-stressed rats.     

The effect of taurine supplementation on oxidative stress in experimental hypothyroidism

The purpose of this study was to investigate the oxidative status in experimental hypothyroidism and the antioxidant effect of taurine supplementation. Forty male Sprague Dawley rats were randomly divided into four groups (group 1, control; group 2, control + taurine; group 3, propylthiouracil (PTU); group 4, PTU + taurine). Hypothyroidism was induced by giving 0.05% PTU in drinking water for 8 weeks. Taurine was supplemented in drinking water at a concentration of 1% for 5 weeks. Plasma (p < 0.05), red blood cell (p < 0.01), liver (p < 0.001) and kidney tissue (p > 0.05) malondialdehyde levels were increased in the PTU group compared with those of the control rats and were decreased in the PTU + taurine group compared with the PTU alone group. No significant changes were observed in glutathione levels of kidney and liver in the PTU group, but taurine supplementation significantly increased the glutathione levels of these tissues. Paraoxonase and arylesterase activities were decreased in the PTU group while taurine supplementation caused no significant changes in paraoxonase and arylesterase activities. These findings suggest that taurine supplementation may play a protective role against the increased oxidative stress resulting from hypothyroidism.     

Effects of chitosan oligosaccharides on intestinal oxidative stress and inflammation response in heat stressed rats

This study was to verify the effects of chitosan oligosaccharides (COS) on intestinal integrity, oxidative status, and inflammatory response in a heat-stressed rat model. A total of 24 male Sprague Dawley rats were randomly divided into 3 treatment: CON, the control group; HS, the heat stress group; HSC, the heat stress group with 200 mg/kg COS. Rats in the HS and HSC group exposed to a cyclical heat stress for 7 consecutive days. The CON and HS group provided basal diet, and the HSC group provided the same diet with 200 mg/kg COS. Compared with the HS group, rats in the HSC group had lower serum diamine oxidase and D-lactate acid level, higher villus height of jejunum and ileum, lower malondialdehyde (MDA) content in duodenum, jejunum, and ileum mucosa, higher glutathione peroxidase (GSH-Px), catalase (CAT) and total antioxidant capacity (T-AOC) activity in duodenum mucosa, higher T-AOC activity in jejunum mucosa, and higher glutathione (GSH) level in ileum mucosa. Compared with the HS group, rats in the HSC group had higher interleukin-10 (IL-10) level, but lower tumor necrosis factor-α (TNF-α) level in duodenum, jejunum, and ileum mucosa. These results indicated that COS may alleviate intestinal damage under heat stress condition, probably by modulating intestinal inflammatory response and oxidative status.     

Antioxidant status,lipid peroxidation,mixed function oxidase and UDP-glucuronyl transferase activities in livers from control and DOCA salt-hypertensive male Sprague Dawley rats

The effects of DOCA-salt hypertensive treatment on hepatic glutathione-dependent defense system, antioxidant enzymes, lipid peroxidation, mixed function oxidase and UDP-glucuronyl transferase activities were investigated in male Sprague Dawley rats.Compared with controls, DOCA-salt hypertensive rats had lower body weights (linked to liver hypertrophy). Mixed function oxidase and p-nitrophenol-UGT activities were not affected by the treatment but a significant lower rate of the glucuronoconjugation rate of bilirubin (p < 0.001) was observed in DOCA-salt hypertensive rats. While cytosolic glutathione contents and glutathione reductase activity were not affected, glutathione peroxidase (p < 0.001), glutathione transferase (p < 0.001) and catalase (p < 0.01) activities were decreased and associated with higher malondialdehyde contents (p < 0.001) in treated rats. The imbalance in liver antioxidant status (increasing generation of cellular radical species), associated with increases in lipid peroxidation, suggests that oxidative stress might be directly related to arterial hypertension in DOCA-salt treated male Sprague Dawley rats.     

Relative and Combined Effects of Selenium, Protein Deficiency and Ethanol on Hepatocyte Ballooning and Liver Steatosis

Oxidative damage plays a key role in alcohol-mediated liver alterations. Selenium, a potent antioxidant, is decreased in alcoholics. This study was conducted to analyse if the supplementation with selenium may alter liver changes in a murine model fed ethanol and/or a 2 % protein-containing diet, following the Lieber–DeCarli design. Adult male Sprague Dawley rats were divided into eight groups which received the Lieber–DeCarli control diet; an isocaloric, 36 % ethanol-containing diet; an isocaloric, 2 % protein-containing diet; and an isocaloric diet containing 2 % protein and 36 % ethanol diet; and other similar four groups to which selenomethionine (1 mg/kg body weight) was added. After sacrifice (5 weeks later), liver fat amount and hepatocyte areas of pericentral and periportal cells were measured, and liver and serum selenium, activity of liver glutathione peroxidase (GPX), and liver malondialdehyde were determined. Ethanol-fed rats showed increased hepatocyte areas and fat accumulation especially when ethanol was added to a 2 % protein diet. Selenium caused a decrease in hepatocyte ballooning and liver fat amount, but an increase in GPX activity, and a marked increase in serum and liver selenium. The present study demonstrates that selenium, added to the diet of rats in the form of seleniomethionine, prevents the appearance of early signs of ethanol-mediated liver injury under the conditions of the Lieber–DeCarli experimental design.     

Vitamin D Supplementation Modulates Blood and Tissue Zinc, Liver Glutathione and Blood Biochemical Parameters in Diabetic Rats on a Zinc-Deficient Diet

Previous studies suggest a protective effect of vitamin D3 on zinc deficiency-induced insulin secretion and on pancreas β-cell function. The aim of this study was to investigate the effect of vitamin D on blood biochemical parameters, tissue zinc and liver glutathione in diabetic rats fed a zinc-deficient diet. For that purpose, Alloxan-induced diabetic rats were divided into four groups. The first group was fed a zinc-sufficient diet while the second group was fed a zinc-deficient diet. The third and fourth groups received zinc-sufficient or zinc-deficient diets plus oral vitamin D3 for 27 days. At the end of the experiment, blood, femur, pancreas, kidney and liver samples were taken from all rats. The serum, femur, pancreas, kidney and liver zinc concentrations, liver glutathione, serum alkaline phosphatase activity, daily body weight gain and food intake were lower in the zinc-deficient rats in comparison with those receiving adequate amounts of zinc. These values were increased in the zinc-deficient group that was supplemented with vitamin D3. The serum total cholesterol, triglycerides, total protein, urea, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and blood glucose values were higher in rats fed a zinc adequate diet, but their concentrations were decreased by vitamin D3 supplementation. The serum total protein levels were not changed by zinc deficiency and vitamin D3 supplementation. These results suggest that vitamin D3 modulates tissue zinc, liver glutathione and blood biochemical values in diabetic rats fed a zinc-deficient diet.     

Effects of Selenium on Liver and Muscle Contents and Urinary Excretion of Zinc,Copper, Iron and Manganese

Selenium is a main component of glutathione peroxidase (GPX), a key antioxidant enzyme. Other elements, such as zinc, copper, manganese and iron, are also involved in the pathogenesis of oxidative damage as well as in other important metabolic pathways. The effects of selenium supplementation on the metabolism of these elements have yield controversial results .The aim of this study is to analyse the effects of selenium supplementation on liver, muscle and urinary excretion of zinc, copper, iron and manganese in a situation of oxidative stress, such as protein deficiency. The experimental design included four groups of adult male Sprague–Dawley rats, which received the Lieber–DeCarli control diet, an isocaloric 2 % protein-containing diet and another similar two groups to which selenomethionine (6 mg/l liquid diet) was added. After sacrifice (5 weeks later), muscle, liver and serum selenium were determined, as well as muscle, liver and urinary zinc, copper, manganese and iron and liver GPX activity and liver malondialdehyde. Selenium addition led to decreased liver copper, increased muscle copper, increased copper excretion and increased liver iron, whereas zinc and manganese parameters were essentially unaltered. Muscle, liver and serum selenium were all significantly correlated with liver GPX activity.     

Protective effect of green tea on lead-induced oxidative damage in rat’s blood and brain tissue homogenates

Recent studies have shown that lead (Pb) could disrupt tissue prooxidant/antioxidant balance which lead to physiological dysfunction. Natural antioxidants are particularly useful in such situation. Current study was designed to investigate efficacy of green tea extract (GTE), on oxidative status in brain tissue and blood caused by chronic oral Pb administration in rats. Four groups of adult male rats (each 15 rats) were utilized: control group; GTE-group (oral 1.5% w/v GTE for 6 weeks); Pb-group (oral 0.4% lead acetate for 6 weeks), and Pb+GTE-group (1.5% GTE and 0.4% lead acetate for 6 weeks). Levels of prooxidant/antioxidant parameters [lipid peroxides (LPO), nitric oxides (NO), total antioxidant capacity (TAC), glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD)] in plasma, erythrocytes, and brain tissue homogenate were measured using colorimetric methods. Pb concentrations in whole blood and brain tissue homogenate were measured by atomic absorption. In Pb-group, levels of LPO were higher while NO and GSH were lower in plasma, erythrocytes, and brain tissue than controls. TAC in plasma, SOD in erythrocytes, and GST in brain tissue homogenate were lower in Pb-group versus control. GTE co-administrated with Pb-reduced Pb contents, increased antioxidant status than Pb-group. In erythrocytes, Pb correlated positively with LPO and negatively with NO, GSH, SOD, and Hb. In brain tissue homogenate, Pb correlated positively with LPO and negatively with GSH. This study suggests that lead induce toxicity by interfering balance between prooxidant/antioxidant. Treatment of rats with GTE combined with Pb enhances antioxidant/ detoxification system which reduced oxidative stress. These observations suggest that GTE is a potential complementary agent in treatment of chronic lead intoxication.     

Comparison of the effects of zinc alone and zinc associated with selenium and vitamin E on insulin sensitivity and oxidative stress in high-fructose-fed rats

PURPOSE: In the present study, we investigated the effect of an association of micronutrients (zinc (Zn), selenium (Se) and vitamin E (vit E)) on insulin activity and antioxidant status in an animal model of insulin resistance, the high-fructose-fed rat. PROCEDURES: Five experimental groups were compared: a control group (C) receiving a standard diet, a high-fructose-fed group (F) where 58% of the diet carbohydrate was fructose, a high-fructose-fed group supplemented with Zn alone (FZn group), a high-fructose-fed group supplemented micronutrients (Zn, Se and vit E) (FMicro group). A fifth group consumed a high-fructose diet and received metformin in the drinking water (200mg/day/rat) (FMet group). Insulin sensitivity was measured using the euglycemic hyperinsulinic glucose clamp technique. Metabolic parameters, trace elements and antioxidant parameters were measured in blood samples from all groups. RESULTS: High-fructose-fed rats were resistant to insulin as indicated by the lower glucose infusion rate. The insulin sensitivity of FZn, FMicro and FMet groups was higher than that of F group, with the highest insulin sensitivity for the FMicro group. No statistically significant difference in glycemia between the groups was observed. The ratio of reduced to oxidized glutathione was higher in FZn and FMicro groups than in all other groups, as a consequence of decreased oxidized glutathione. CONCLUSION: Our results provide direct evidence that micronutrients have a beneficial effect on insulin sensitivity and some components of the antioxidant defense system in an animal model of insulin resistance.     

Vitamin E supplementation in the mitigation of carbon tetrachloride induced oxidative stress in rats

Oxidative stress is implicated in the pathophysiology of a number of chronic diseases including atherosclerosis, diabetes, cataracts and accelerated aging. The aim of this study was to elucidate the protective role of vitamin E supplementation when oxidative stress is induced by CCl4 administration, using the rat as a model. Rats were fed diets for four weeks either with or without dl-alpha-tocopherol acetate supplementation. Half of the rats (n = 9) from each of the diet groups were then challenged with CCl4 at the completion of the four week diet period. Plasma levels of 8-iso-PGF(2alpha), antioxidant micronutrients and antioxidant enzyme activities were measured to examine changes in oxidative stress subsequent to the supplementation of dl-alpha-tocopherol in the diet. Plasma alpha-tocopherol (vitamin E) concentrations were higher for the groups supplemented with dl-alpha-tocopherol acetate, however the supplemented diet group that was subsequently challenged with CCl4 had significantly lower (p <0.001) plasma alpha-tocopherol concentration than the dl-alpha-tocopherol acetate diet group that was not challenged with CCl4. Total plasma 8-iso-PGF(2alpha) concentration was elevated in diet groups challenged with CCl4, however, the concentration was significantly lower (p <0.001) when the diet was supplemented with dl-alpha-tocopherol acetate. The antioxidant enzymes were not influenced by either dietary alpha-tocopherol manipulation or by the inducement of oxidative stress with CCl4. Plasma concentrations of trans-retinol (vitamin A) were reduced by CCl4 administration in both the dl-alpha-tocopherol acetate supplemented and unsupplemented diet groups. The results of this study indicate that dl-alpha-tocopherol acetate supplementation was protective of lipid peroxidation when oxidative stress is induced by a pro-oxidant challenge such as CCl4.     

Oxidative stress and serum paraoxonase activity in experimental hypothyroidism: effect of vitamin E supplementation

Thyroid hormones are associated with the oxidative and antioxidative status of the organism. Since data on the oxidative status of hypothyroidism are limited and controversial, we investigated the oxidant and antioxidant status and serum paraoxonase/arylesterase activities in propylthiouracil-induced hypothyroidism and examined the effect of vitamin E supplementation on this experimental model. Forty male Sprague Dawley rats were randomly divided into four groups (group 1, control; group 2, control + vitamin E; group 3, propylthiouracil; group 4, propylthiouracil + vitamin E). Plasma, red blood cell, liver, heart and skeletal muscle malondialdehyde levels were increased in the propylthiouracil-treated group compared with the control rats and were decreased in propylthiouracil + vitamin E group compared with the propylthiouracil-treated group. Vitamin E supplementation also significantly increased liver and kidney reduced glutathione levels in propylthiouracil treated animals. Serum paraoxonase and arylesterase activities were decreased in propylthiouracil treated group and vitamin E supplementation caused significant increase in serum paraoxonase activity compared with the propylthiouracil-treated rats. These findings suggest that hypothyroidism is accompanied with increased oxidative stress and vitamin E supplementation exerts beneficial effects on this situation.     

慢性乙醇摄入大鼠肝脏醇脱氢酶和谷胱甘肽硫转移酶活性影响

为探讨长期摄入乙醇大鼠肝脏ＡＤＨ和ＧＳＴ活性的动态变化,旨在为酒精中毒的发病机理提供实验依据,进行了下述实验研究。选用体重１００～１２０ｇＳＤ雄性大鼠４８只,随机分成两组：（１）对照组：２４只喂普通饲料,饮用自来水,（２）乙醇组：２４只白天饮用１０％蔗糖水,夜间饮用１０５乙醇水溶液,平均每只实验动物的乙醇摄入量为８．０ｇ／ｋｇ体重／ｄ,饲料同对照组。实验开始后的３０ｄ、６０ｄ时分批处死动物,第９０天时处死全部动物,除肉眼观察肝脏形态学改变外,同时留取病理标本和进行组织中ＡＤＨ和ＧＳＴ活性测定,结果显示：（１）大鼠肝细胞胞浆中ＡＤＨ活性,在服用乙醇３０ｄ时即可看到明显减低,较对照组有显著差别（Ｐ＜０．０５）,至实验９０ｄ结束时,其减低的更明显（Ｐ＜０．０１）．（２）大鼠肝细胞胞浆中ＧＳＴ活性　在６０ｄ和９０ｄ时乙醇组较对照组均明显减低,经统计学处理均有显著差别（Ｐ＜０．０１）。上述结果提示肝脏ＡＤＨ和ＧＳＴ活性表达在酒精性肝病发病机制中起着重要作用。     

Effect of dietary cardiac glycosides on blood pressure regulation in rats

To investigate the possible physiological significance of dietary cardiac glycosides in blood pressure regulation, the blood pressure of normal Sprague Dawley rats raised on a regular diet, which naturally contains large amounts of Na+-pump inhibitors, was compared with that of rats on a purified synthetic diet, which contains no Na+-pump specific inhibitors, and with that of rats on a synthetic diet supplemented with 10 microg x mL(-1) ouabain or 10 microg x mL- convallatoxin in the drinking water. After 6 weeks on the synthetic diet, the systolic blood pressure in the synthetic diet group was significantly elevated (145 +/- 5 vs. 128 +/- 4 mmHg, P < 0.05). At 10 weeks it reached a plateau (154 +/- 3 vs. 122 +/- 3 mmHg, P < 0.05). Plasma renin activity and Na+ level were significantly higher in animals fed synthetic diets than in the regular diet group (P < 0.01). Administration of either losartan or lisinopril or a switch to a low salt synthetic diet (0.03% sodium) normalized the synthetic diet-induced high blood pressure. Supplementation of the synthetic diet with the cardiac glycosides delayed the onset of the increase in blood pressure for 4 weeks. Plasma aldosterone levels were approximately doubled in the cardiac glycoside-treated groups. Higher plasma Na+ levels and hematocrit values present in the synthetic diet group were normalized by the glycoside supplements. These results suggest that supplemental dietary cardiac glycosides exert bidirectional effects on blood pressure regulation through actions that modulate extracellular fluid and electrolyte balance.     

Influence of age on lead-induced oxidative stress in rat

Influence of age on lead-induced oxidative stress was investigated in young, adult, and old rats maintained on 0.2% lead acetate (2000 ppm lead) in drinking water for 3 mo. The lead-induced depletion of blood and liver reduced glutathione was about equal in young and adult but not in old rats. The increases in blood, liver, and brain oxidized glutathione and blood and liver superoxide dismutase levels were related to the accumulation of lead in these tissues and followed the order young >adult>old. The lead-induced inhibition of blood δ-aminolevulinic acid dehydratase activity, lowering in hemoglobin, and enhanced urinary excretion of δ-aminolevulinic acid were independent of variation in age. The results indicate that young rats may be most sensitive, whereas old rats may be most resistant to some of the oxidative effects of lead examined, which may be related to the accumulation of lead.     

Manganese Supplementation Reduces the Blood Cholesterol Levels in Ca-Deficient Ovariectomized Rats

Manganese (Mn) is an essential element for normal development and bodily functions in humans. In the present study, we examined whether Mn supplementation can alter the serum lipid parameters and liver function in Ca-deficient ovariectomized (OVX) rats. Sixty female Sprague–Dawley rats (6 weeks) were divided into five groups and bred for 12 weeks: sham-operated control group (Sham), OVX Ca deficiency group (OLCa) with Ca-deficient diet (0.1% Ca modified AIN-93N diet), OVX Ca deficiency and Mn supplementation group (OLCaMn), OVX with adequate Ca group (OACa; 0.5% Ca AIN-93N diet), and OVX with adequate Ca and Mn supplementation group (OACaMn). A low Ca diet increased the liver weight and serum levels of GOT, GPT, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in OVX rats. Mn supplementation decreased these parameters in Ca-deficient OVX rat. The results of our study suggest Mn supplementation results in reductions of the blood cholesterol levels, which show an increase due to Ca deficiency in OVX rats.