Veratric acid ameliorates hyperlipidemia and oxidative stress in Wistar rats fed an atherogenic diet

An investigation was made to reveal the protective effects of veratric acid (VA), a phenolic acid against atherogenic diet-induced hyperlipidemic rats. Male albino Wistar rats were fed with atherogenic diet (4% cholesterol, 1% cholic acid, and 0.5% 2-thiouracil) daily for 30 days and treated with VA (40 mg/kg body weight) daily for a period of 30 days. Rats fed with atherogenic diet showed significant (P < 0.05) elevation in the level of plasma lipids, systolic and diastolic blood pressure, oxidative stress markers (thiobarbituric acid reactive substances, lipid peroxides) and significant (P < 0.05) reduction in the activities of enzymatic (superoxide dismutase, catalase, glutathione peroxidase) and non-enzymatic (vitamin C, vitamin E, and reduced glutathione) antioxidants in erythrocytes, plasma, and tissues (liver, kidney, and aorta). Oral administration of VA (40 mg/kg body weight) for 30 days to atherogenic diet fed rats markedly attenuates systolic, diastolic blood pressure and lipid peroxidation products. Further, VA treatment significantly improved enzymatic and non-enzymatic antioxidants levels and showed beneficial effects on lipid profile in atherogenic diet rats. All the above alterations were supported by histopathological observations. These results indicate that oral administration of VA ameliorates atherogenic diet-induced hyperlipidemia in rats by its free radical scavenging; improving the antioxidants and lipid lowering properties.     

Evaluation of the anti-atherogenic potential of chrysin in Wistar rats

Hypercholesterolemia is one of the major risk factors that precipitate coronary heart disease and atherosclerosis. Oxidative stress is believed to contribute to the pathogenesis of hypercholesterolemic atherosclerosis; hence, various antioxidant compounds are being evaluated for potential anti-atherogenic effects. In the present study, the putative anti-atherogenic and antioxidant efficacy of a flavonoid, chrysin, was evaluated in an experimental model of atherosclerosis. In male, albino Wistar rats fed an atherogenic diet for 45 days and treated with saline, significantly higher mean levels of serum lipid profile parameters (total cholesterol, triglycerides, low-density, and very low-density lipoprotein cholesterol), lower mean levels of high-density lipoprotein cholesterol and higher mean serum levels of hepatic marker enzymes (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase) were observed when compared with the levels in rats fed a control diet. In addition, significantly lower mean hepatic levels of lipoprotein lipase, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase) and non-enzymatic antioxidants (reduced glutathione, and vitamins C and E), and a significantly higher mean level of hepatic malondialdehyde (MDA) were noted in comparison to the values in control rats. In atherogenic diet-fed rats that received chrysin orally (200 mg/kg b.wt) for 15 days, starting 30 days after the start of the atherogenic diet, significantly lower mean serum levels of lipid profile parameters (except for HDL-cholesterol which was elevated), hepatic marker enzymes, and significantly higher mean hepatic levels of LPL, HMG-CoA reductase, enzymatic, and non-enzymatic antioxidants and significantly lower mean levels of hepatic MDA were noted, compared to the values in atherogenic diet-fed, saline-treated rats. Histopathological studies appeared to suggest the protective effect of chrysin on the hepatic tissue and aorta of atherosclerotic rats. These results suggest that chrysin has anti-atherogenic potential in an experimental setting.     

Green tea catechins, alleviate hepatic lipidemic-oxidative injury in Wistar rats fed an atherogenic diet

In the present study, the efficacy of green tea catechins (GTC from the plant Camellia sinensis), with epigallocatechin gallate (EGCG), as the major component, was studied in relation to hepatic oxidative abnormalities in atherosclerotic rats. When male albino Wistar rats were fed an atherogenic diet for 30 days and then treated with saline for 7 or 15 days, there was a significant decline in hepatic mean activities of antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase and glutathione-S-transferase), and non-enzymatic antioxidants (reduced glutathione, vitamins C and E) while there was a significant elevation in the mean level of hepatic malondialdehyde (MDA), in comparison to the values noted in control rats fed a normal diet. In addition, a concomitant increase in the activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) was noted, when compared to the values in control rats. Following intraperitoneal administration of GTC (100 mg/kg) for 7 or 15 days to rats fed the atherogenic diet, significantly higher mean activities of enzymatic and non-enzymatic antioxidants and lower mean levels of MDA in hepatic tissue and lower mean activities of AST, ALT, ALP and LDH in serum were observed, compared to the values in the rats fed the atherogenic diet and treated with saline. Histopathological studies were performed to provide direct evidence of the atherogenic diet-induced hepatic changes and of the hepatoprotective effect of GTC. These results suggest that EGCG as a major component of green tea catechins may protect against the hepatic abnormalities occurring in Wistar rats fed an atherogenic diet.     

Combined effect of some physical and chemical factors

The effect of simultaneous exposure to noise and dimethylformamide (DMF), noise and xylol and also vibration and lead on the metabolism of the myocardium of albino rats was studied. Combined effect of the factors was examined by the method of bifactorial design of the experiment. The animals were exposed to noise, intensity 46, 85 and 95 dB (2 and 4 hours), DMF in doses of 0.25, 1.00 and 5.00 ml . kg-1 (5 days in a week), and xylol in a concentration of 300 mg . m-3 (4 hours, 5 days in a week) for a period of 1.5 months, as also to vibration, intensity 100 Hz, 4 m . sec-2 (2 hours) and lead acetate in a dose of 20 mg . kg-1 (daily for a period of 10 days). The activity of GlDG, SucDG, LDG, G6PDG, G6P-ase, PGM and CytO in the myocardium of experimental and control animals was examined. Disturbances in metabolic and energy processes in the heart muscle were established after both isolated and combined exposure to the effect of the factors. Results of bifactorial variance analysis demonstrate that combined effect of noise and DMF results in not only independent effect of the two factors, but also in their interaction. Isolated effect of two factors (vibration and lead) can be assessed according to the relationship of some enzymes; their interaction can be noticed in GlDG, ATP-ase and G6P-ase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of atherogenic diet on young farm pigs.

This study was designed to assess the usefulness of young farm pigs as an experimental model for hypercholesterolemia. In order to test this, we investigated both serologic and electrocardiographic effects of atherogenic diet. Four-week-old pigs were fed an atherogenic diet for 8 weeks. No arrhythmia was observed on ECG in all animals. There were no significant difference between control and atherogenic diet group on the values of ECG parameters. However, plasma lipids values of atherogenic diet group were significantly (p less than 0.05) higher than those of control diet group. Thus, hypercholesterolemia was induced in young farm pigs by feeding atherogenic diet in a relatively short time. This fact suggests that young farm pigs may be an useful model for further studies of the effect of hypercholesterolemia on cardiovascular function and the early pathogenesis of atherosclerosis.     

Glycosaminoglycan content in tissues and body fluids of rats treated with atherogenic diet.

An increase of total glycosaminoglycan content in aortic wall and liver as well as changes in the concentration of glycosaminoglycan fractions in aorta, skin, liver, and blood serum were found in white rats fed with atherogenic diet. Urinary excretion of glycosaminoglycans was increased in experimental animals.     

Effects of simvastatin treatment on oxidant/antioxidant state and ultrastructure of diabetic rat myocardium

In the present study we investigated the effects of simvastatin treatment on lipid metabolism and peroxidation, antioxidant enzyme activities and ultrastructure of the diabetic rat myocardium. Diabetes was induced by single injection of streptozotocin (45 mg/kg i.p.). Eight weeks after induction of diabetes, a subgroup of control and of diabetic rats was treated with simvastatin for 4 weeks (10 mg/kg/day, orally). Blood glucose, plasma cholesterol and triacylglycerol, as well as levels of cardiac thiobarbituric acid reactive substances (TBARS) were significantly increased in diabetic rats. The activities of antioxidant enzymes, catalase (CAT) and glutathione peroxidase (GSHPx), were also elevated in the diabetic myocardium. Treatment with simvastatin markedly reduced serum triacylglycerol and cholesterol, and partially controlled hyperglycemia in diabetic animals. The increased activation of antioxidant enzymes and the excess of lipid peroxidation measured by TBARS were completely reversed by simvastatin treatment. Diabetic rats displayed ultrastructural ischemia-like alterations of cardiomyocytes and capillaries, which support oxidative stress-induced tissue remodelling. In the diabetic myocardium simvastatin treatment partly attenuated angiopathic and atherogenic processes, detected by electron microscopy. These results suggest that simvastatin, known as a lipid-lowering drug, may positively affect diabetes induced cardiovascular complications via reducing risks of atherosclerotic pathological processes, such as imbalance between oxidant and antioxidant state.     

Process of fibrin depolymerization and non-enzymatic fibrinolysis in rabbits receiving atherogenic rations with addition of antioxidants

The rabbits were kept on atherogenic ration for 2 months. This diet contained 0.3 mg/kg of cholesterol. In blood plasma of animals the authors observed a sharply reduced non-enzymatic fibrinolysis and depolymerization activity of non-stabilized fibrin. The addition of antioxidants and alpha-tocopherol (10 + 10 mg/kg) for 1 month to the atherogenic ration protected from the disturbance of the system hemostasis and normalized the depolymerization of non-stabilized fibrin.     

Preliminary observations, at the ultrastructural level, on the reactivity of cerebral arteries from New Zealand rabbits to combined atherogenic stimuli (hypercholesterol diet and hypertension)

Both in monkeys (Rhesus and Cynomolgus) and in New Zealand rabbits fed an atherogenic diet, a marked delay in the appearance of atherosclerotic lesions of the cerebral arteries in comparison with other arterial districts has been observed. This appearance has been described in monkeys as relatively earlier if hypertension is added to the atherogenic diet. Preliminary observations on a little group of rabbits on a 3 months hypercholesterolic diet, subjected to Goldblatt aortic coarctation, have shown an increase of blood pressure and a severe gross atherosclerotic involvement of aorta, resembling the one obtainable after 6 months of atherogenic diet. Histologically, the aorta predominantly shows lesions of the fatty streaks type with necrotic areas in the deep; the carotid lesions show some lipid in smooth muscle cells disseminated in a sub-endothelial "edematous" space (rich in protein). The cerebral arteries do not show any lesion. At TEM, the aortic lesions look sometimes as advanced plaques with an initial fibrosis at the surface; the carotid lesions are characterized by a granular deposit in the sub-endothelial space in which some smooth muscle cells (with lipid in the cytoplasm) are present; in the cerebral arteries only the presence of collagen fibers among the smooth muscle cells of the media, never observed in the animals fed the atherogenic diet alone, has sometimes been noted.     

The Influence of Fluoride Ions upon Selected Enzymes of Protein Metabolism in Blood Plasma of Rabbits with Hypercholesterolemia

Three-month studies were performed on 18 adult rabbits of New Zealand breed divided into three groups, with six animals in each: a control group on standard diet, a cholesterol group receiving 500 mg of cholesterol/100 g of feed per rabbit per 24 h (CH group), and a cholesterol + fluorine group (CH + F group) receiving 500 mg of cholesterol/100 g of feed per rabbit per 24 h and 3 mg of F(-)/kg of body weight per 24 h. The conducted studies proved that cholesterol in the applied dosage (500 mg cholesterol per rabbit per 24 h) has an atherogenic action. Fluoride ions administered together with a 500-mg cholesterol atherogenic diet inhibit the atheromatosic changes in the aorta. The concentration of plasma cholesterol was elevated in both study groups when compared to the control group but decreased in the CH + F group when compare to the CH group. The influence of fluoride ions has been examined upon the activity of alanine aminotransferase, aspartate aminotransferase, and glutamate dehydrogenase (GLDH) in the plasma in the liver of rabbits in the course of experimental hypercholesterolemia. Increase in the activity of study enzymes has been observed in the blood plasma, which may be due to damage occurring to hepatocytes of the animals examined (a statistically significant increase in the activity of GLDH in the plasma). In the liver, the inhibition of activity for all examined enzymes has been observed in the group of rabbits with hypercholesterolemia, which testifies the disturbances in protein metabolism in examined animals. The addition of sodium fluoride to the diet rich in cholesterol results in "removing the block" on those activities, which increase. We suppose that the permeability of the hepatocyte membrane was elevated, so the activities of examined enzymes increased in the plasma ("escape" to plasma). On the one hand, fluoride ions result in probable lesion of hepatocytes membranes; on the other hand, they inhibit the atheromatosic changes in the aorta.     

Cardiovascular oxidative stress is reduced by an ACE inhibitor in a rat model of streptozotocin-induced diabetes

Blockade of the renin-angiotensin system (RAS) reduces cardiovascular morbidity and mortality in diabetic patients. Ang II-mediated generation of reactive oxygen species (ROS) has been suggested to be involved in several diabetic complications. We investigated whether the inhibition of Ang II production with an ACE inhibitor (ACEi) reduces oxidative stress and limits structural cardiovascular remodeling in a rat model of streptozotocin (STZ)-induced diabetes. Diabetic rats were treated for 7 weeks with an ACEi (lisinopril, 5 mg/kg/d), an antioxidant (N-acetyl-l-cysteine (NAC), 0.5 g/kg/d) and their combination. At sacrifice, ROS in the myocardium and thoracic aorta, LV myocyte number and size and aorta morphology were determined by quantitative histological methods. Superoxide and hydroxyl radical content, detected by dihydroethidium (DHE) and 8-hydroxydeoxyguanosine (8-OHdG), were 6.7 and 4.5-fold, respectively, higher in diabetic myocardium than in non-diabetic controls (p<0.001). The amount of superoxide was 5-fold higher in the thoracic aorta of diabetic rats compared to controls (p<0.001). Diabetes caused a modest increase in myocyte volume (+13%, p<0.01), a reduction of LV myocyte number (-43%, p<0.001), an accumulation of collagen around coronary arterioles (1.9-fold increase, p<0.01) and a decrease in arterial elastin/collagen ratio (-63%, p<0.001) compared to controls. Treatment with the ACEi attenuated ROS formation and prevented phenotypic changes in the heart (cardiomyocyte hypertrophy, perivascular fibrosis) and in the aorta of diabetic rats to the same extent as NAC. The absence of an additive effect, suggests a common mechanism of action, through the reduction of oxidative stress.     

Puerarin decreases serum total cholesterol and enhances thoracic aorta endothelial nitric oxide synthase expression in diet-induced hypercholesterolemic rats

Hypercholesterolemia is a dominant risk factor for the development and progression of atherosclerosis and cardiovascular diseases. Natural compounds have been proved to be useful in lowering serum cholesterol to slow down the progression of cardiovascular diseases. Pueraria lobata is employed clinically to treat cardiovascular diseases in China. In the present study, the atheroscleroprotective potential of the herb's major active compound, puerarin, was investigated by monitoring serum lipid profile and major enzyme expressions on cholesterol homeostasis in Sprague-Dawley rats fed with control diet, hypercholesterolmic diet or hypercholesterolmic diet plus administration of puerarin (300 mg/kg/day, p.o.) for 4 weeks. Puerarin markedly attenuated the increased total cholesterol induced by hypercholesterolmic diet in both serum and liver. It caused a significant reduction in the atherogenic index. Expression of mRNA for hepatic 7alpha-hydroxylase (CYP7A1) was significantly enhanced but not for those of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and lanosterol 14alpha-demethylase (CYP51). To further explore the atheroscleroprotective potential of puerarin, acetylcholine induced endothelium-dependent vasorelaxation and endothelial nitric oxide synthase (eNOS) expression on isolated thoracic aortas were analyzed. Animals administered with puerarin suppressed the hypercholesterolemic diet induced impairment of eNOS expression, whereas there was no significant difference in the endothelium-dependent vasorelaxation among various groups of animals. These data indicated that puerarin reduced the atherogenic properties of dietary cholesterol in rats. Its hypocholesterolemic function may be due to the promotion of cholesterol and bile acids excretion in liver. Whether puerarin targets directly on cholesterol homeostasis or both cholesterol homeostasis and endothelial function remains to be determined.     

Vitamin A deficiency induces prooxidant environment and inflammation in rat aorta

We evaluated whether nutritional vitamin A deficiency generates oxidative stress and inflammation in aorta. Wistar male rats (21 days old) were given free access to a control (8 mg retinol as retinyl palmitate/kg) or a vitamin A- deficient diet for three months. One group of deficient animals was fed with the control diet fifteen days before sacrifice. Thiobarbituric acid-reactive substances (TBARS) and nitrite concentration where both analyzed in serum and aorta. Aorta Copper-Zinc Superoxide dismutase (CuZnSOD), Glutathion peroxidase (GPx) and Catalase (CAT) activities were measured. In addition, binding activity of the nuclear factor- kB (NF-kB), inducible and endothelial Nitric Oxide synthase (iNOS and eNOS, respectively) and Ciclooxygenase-2 (COX-2) expressions were determinated in aorta. Rats fed the vitamin A- deficient diet were characterized by sub-clinical plasma retinol concentration and showed increased serum and aorta concentrations of TBARS compared to controls. Lower than control activities of CuZnSOD, GPx, and CAT were observed in aorta of the vitamin A- deficient group. The binding activity of NF- kB was higher in vitamin A- deficient animals than controls. In addition, NO production evaluated as nitrite concentration increased in aorta and serum, associated with a higher expression of iNOS, eNOS and COX-2 in aorta of vitamin A-deficient rats. The incorporation of vitamin A into the diet of vitamin A-deficient rats reverted the changes observed in TBARS level, CuZnSOD and GPx activities, nitrite concentration and also, iNOS, eNOS and COX-2 expression. Prooxidant environment and inflammation are induced by vitamin A deficiency in rat aorta.     

Exercise training promotes expression of apelin and APJ of cardiovascular tissues in spontaneously hypertensive rats

Because apelin may play an important regulatory role in human cardiac dysfunction, we investigated alterations in cardiovascular content of apelin and its receptor, APJ, during hypertension and the effect of exercise training on the cardiovascular apelin/APJ system in hypertensive animals. Spontaneously hypertensive rats (SHRs) underwent swimming training consisting of 54 swimming sessions of 60 min each (6 days/week for 9 weeks). Systolic blood pressure (SBP) was verified weekly by tail-cuff plethysmography. Apelin levels in plasma and cardiovascular tissues were determined by radioimmunoassay. The level of apelin/APJ mRNA was determined by RT-PCR. SHRs showed severe hypertension and pathological cardiomegaly. The level of apelin immunoreactivity (apelin-ir) in plasma and ventricular and aortic tissues was lower, by 40%, 40% and 42% (all P<0.01), respectively, in SHRs than in control Wistar-Kyoto rats, and the mRNA level of apelin and APJ in myocardium and aorta was markedly decreased. Compared with sedentary SHRs, swimming-trained SHRs showed decreased SBP and elevated mRNA expression of apelin and APJ in cardiovascular tissues and elevated apelin-ir level in plasma, myocardium and aorta (all P<0.01). SBP and level of apelin-ir in plasma and cardiovascular tissues were negatively correlated. Long-term swimming training relieved the pathogenesis of hypertension and reversed the downregulation of the cardiovascular apelin/APJ system induced by hypertension, which suggests that the improving effect of exercise training on hypertension could be mediated by upregulating the cardiovascular apelin/APJ system.     

Reactivity of mesenteric and aortic rings from trained rats fed with high caloric diet

A strong association between the benefits of physical exercise on the cardiovascular disease with an improvement of the endothelium-derived relaxing factor production has been consistently shown. The purpose of this study was to evaluate the effect of exercise training associated with high caloric diet in the reactivity of rat mesenteric and aortic rings. Experimental protocol consisted of 4 weeks of high caloric diet consumption previous to 4 weeks of run training (1.2 km/h, 0% grade, in sessions of 60 min, 5 days/week). Concentrations of triglycerides, glucose, insulin and nitrite/nitrate levels were measured and atherogenic index was calculated. Concentration-response curves to acetylcholine (10 nM-100 microM), sodium nitroprusside (100 pM-100 nM) and phenylephrine (1 nM-3 microM) were obtained. Exercise training reduced body mass (6%) and triglyceride levels (about 54%), without changes in glucose and insulin concentrations. An improvement of endothelium-dependent relaxation responses to acetylcholine in mesenteric and aortic rings was observed in trained group. No changes were seen for sodium nitroprusside and phenylephrine. In conclusion, our study is the first to show clearly that run training promotes an improvement of the endothelium-dependent relaxing response in aorta and mesenteric rings from rats fed with high caloric diet and that is associated with increase of NO production.     

Ripe beans of Canavalia ensiformis (jackbean) as feed ingredient for monogastric animals

Feeding and digestibility experiments were carried out in male growing albino rats to estimate the acceptable amount of Canavalia beans in the diet for monogastric farm animals. A reduced intake and live weight gain was observed with a ration containing 20% beans, but not with those containing 5 and 10% beans. No harmful effects were observed.     

Effects of phenotype, sex, and diet on plasma lipids in LA/N-cp rats

The LA/N-corpulent (cp) rat is a recently developed congenic strain which exhibits obesity. The effects of phenotype and sex on serum and lipoprotein lipid content were examined in LA/N-cp rats fed either a control or an atherogenic diet high in saturated fat and protein. Obese rats were pair-fed to equivalent lean animals. Results from this study indicate that sex, phenotype, and diet exert significant effects on plasma and lipoprotein cholesterol content. Plasma cholesterol levels were higher in obese compared with lean rats, females than in males, and rats consuming the atherogenic diet compared with the control diet. Plasma and lipoprotein triglyceride levels were significantly increased only in obese compared with lean animals. The increased plasma cholesterol and triglyceride was observed primarily in the chylomicron and very low density lipoprotein fractions. Increased levels of plasma cholesterol were not a result of increased dietary cholesterol absorption or increased liver cholesterol biosynthesis. These data suggest that LA/N-cp rats can serve as a unique rodent model for the study of the interrelationships between hyperlipidemia, obesity, and coronary heart disease.     

冠状动脉粥样硬化大鼠实验动物模型的改进与评价

目的通过对文献报道的动脉粥样硬化大鼠造模方法的改进,建立一种适合进行心血管疾病研究的冠状动脉粥样硬化Wistar大鼠模型。方法将40只大鼠随机分为对照组与模型组,对照组15只,模型组25只。模型组高脂饲料喂养配合前3个月,每月按15万U/kg每月腹腔注射维生素D3一次,对照组喂养普通饲料,造模时长150 d。实验结束后通过对血管内皮、脂代谢、炎症浸润几个方面对模型大鼠进行考察。结果证实模型组大鼠较对照组血清LDL-C、CHO、TG水平明显升高,HDL-C/LDL-C、NO/ET-1值明显降低;AI值显著增高;血清NO、ET-1、ox-LDL、AngⅡ、sICAM-1表达明显增高;HE染色显示：模型组大鼠冠状动脉出现血栓、内皮破坏、粥样斑块形成,血管壁钙化情况;心肌纤维组织增生,炎细胞浸润,心肌轻度变性;主动脉出现动脉粥样硬化斑块形成,而对照组无病变产生。结论本方法能够提供一种稳定的、复制性好的用于冠状动脉粥样硬化实验研究的大鼠模型。     

Protective effects of N-acetyl cysteine on lipid peroxide metabolism on isoproterenol-induced myocardial infarcted rats

The present study was designed to evaluate the preventive effects of N-acetyl cysteine on lipid peroxide metabolism in isoproterenol (ISO) induced myocardial infarcted rats. Male albino Wistar rats were pretreated with N-acetyl cysteine (5 and 10 mg/kg) daily for a period of 14 days. After the pretreatment period, ISO (100 mg/kg) was subcutaneously injected to rats twice at an interval of 24 h. Increased activities of serum creatine kinase, creatine kinase-MB, lactate dehydrogenase, and increased intensities of serum lactate dehydrogenase-isoenzyme bands (LDH-1, LDH-2) were observed in ISO-induced rats. The heart lipid peroxidation products were significantly increased, and the antioxidant system was significantly reduced in ISO-induced rats. Pretreatment with N-acetyl cysteine (5 and 10 mg/kg) to ISO-induced rats showed significant effects on all the biochemical parameters studied. Histopathological findings of the myocardium also showed the protective role of N-acetyl cysteine in ISO-induced rats. Furthermore, in vitro study confirmed the potent-free radical scavenging activity of N-acetyl cysteine. The effect at a dose of 10 mg/kg of N-acetyl cysteine was more pronounced than the dose, 5 mg/kg. The results of our study show that N-acetyl cysteine protects the heart against ISO-induced myocardial infarction by its free radical scavenging effect.