Exercise conditioning attenuates the hypertensive effects of nitric oxide synthase inhibitor in rat

Cerebrovascular damage after midlife transient hypertension in non-transgenic and Alzheimer's disease rats

Hypertension, including transient events, is a major risk factor for developing late-onset dementia and Alzheimer's disease (AD). Anti-hypertensive drugs facilitate restoration of normotension without amelioration of increased dementia risk suggesting that transient hypertensive insults cause irreversible damage. This study characterized the contribution of transient hypertension to sustained brain damage as a function of normal aging and AD. To model transient hypertension, we treated F344TgAD and non-transgenic littermate rats with L-NG-Nitroarginine methyl ester (L-NAME) for one month, ceased treatment and allowed for a month of normotensive recovery. We then examined the changes in the structure and function of the cerebrovasculature, integrity of white matter, and progression of AD pathology. As independent factors, both transient hypertension and AD compromised structural and functional integrity across the vascular bed, while combined effects of hypertension and AD yielded the largest deficits. Combined effects of transient hypertension and AD genotype resulted in loss of cortical myelin particularly in the cingulate cortex which is crucial for cognitive function. Increased cerebral amyloid angiopathy, a prominent pathology of AD, was detected after transient hypertension as were up- and down-regulation of proteins associated with cerebrovascular remodeling - osteopontin, ROCK1 and ROCK2, in F344TgAD rats even 30 days after restoration of normotension. In conclusion, transient hypertension caused permanent cerebrovasculature and brain parenchymal damage in both normal aging and AD. Our results corroborate human studies that have found close correlation between transient hypertension in midlife and white matter lesions later in life outlining vascular pathologies as pathological links to increased risk of dementia.

Effects of exercise training on hepatic oxidative stress and antioxidant status in aged rats

This study investigated the effects of exercise training on oxidative stress, and antioxidant defense markers in the liver tissues of young and aged rats. Two age groups of 4-(young) and 20-months-(aged) old male Wistar rats were performed exercise training program consisted of swimming exercise for 8 weeks. The biomarkers of pro/antioxidant status malondialdehyde (MDA), protein carbonyl (PC), 8-hydroxy-2'-deoxyguanosine (8-OHdG), total glutathione (GSH) and superoxide dismutase (SOD) were assessed by commercially available kits. PC levels were higher in the untrained aged rats compared to the young groups and exercise training decreased PC levels (p < 0.05). 8-OHdG levels were higher in the aged groups (p < 0.05). MDA and GSH levels and SOD activity did not differ significantly between the groups (p > 0.05). The present findings indicate that exercise training prevents aging-induced hepatic oxidative damage especially in the proteins.

Swimming training prevents alterations in acetylcholinesterase and butyrylcholinesterase activities in hypertensive rats

BACKGROUND

Cholinergic enzyme activities are altered in hypertension, reflecting a low-grade inflammation. Regular physical exercise exerts anti-inflammatory effects and has been described as a coadjutant in the treatment of hypertension. In this study, we investigated the effect of 6 weeks of swimming training on cholinergic enzyme activities (acetylcholinesterase and butyrylcholinesterase) in Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats.

METHODS

The rats were divided into 4 groups: control (n = 10), exercise (n = 10), L-NAME (n = 10), and exercise L-NAME (n = 10). The animals were trained 5 times per week in an adapted swimming system for 60 minutes with a gradual increase of the workload up to 5% of animal's body weight. Enzyme activities were measured spectrophotometrically in lymphocytes, whole blood, and serum.

RESULTS

A significant rise in acetylcholinesterase activity was observed in lymphocytes and whole blood as well as in serum butyrylcholinesterase activity in the L-NAME group when compared with the other groups (P < 0.05), and the increase in cholinesterase activities was positively correlated with the rise in blood pressure (r = 0.5721, r = 0.6121, and r = 0.5811, respectively). Swimming training was efficient in preventing these alterations in the exercise L-NAME group, which displayed values similar to those of the control group. Exercise training demonstrated a significant hypotensive effect in hypertensive rats.

CONCLUSIONS

Exercise training was shown to prevent increased cholinesterase related to inflammatory processes in hypertensive rats, providing a new insight about protective exercise mechanisms to avoid hypertension-related inflammation.

The effect of bisphenol A on some oxidative stress parameters and acetylcholinesterase activity in the heart of male albino rats

Bisphenol A (BPA) is an endocrine disrupting chemical used on a wide range in industry. Several studies reported that BPA may cause cardiovascular disorders in humans and animals. The present study aims to investigate the effect of BPA on the heart of adult male rats. The rats received a daily oral administration of BPA (25 mg/kg for 6 weeks and 10 mg/kg for 6 and 10 weeks). It was found that BPA at the two studied doses induced a significant increase in malondialdehyde, and a significant decrease in catalase after 6 weeks. Moreover, a significant decrease in reduced glutathione and acetylcholinesterase (AchE) activity was observed after treatment with the two doses of BPA throughout the studied time intervals. The two doses (25 and 10 mg/kg) resulted in a significant decrease in nitric oxide (NO) levels after 6 and 10 weeks, respectively. A significant increase in body weight gain occurred in all animals after BPA treatment. These results suggest that BPA has cardiotoxic effects which are mediated by the oxidative stress resulting from the overproduction of free radicals, the deficiency of NO and the inhibition of AchE leading to cholinergic activation. The obesity promoting effect of BPA may also participate in the observed cardiovascular disturbances.

Effects of administration of IH901, a ginsenoside intestinal metabolite, on muscular and pulmonary antioxidant functions after eccentric exercise

This study was conducted to investigate whether administration of IH901, a ginseng intestinal metabolite, ameliorates exercise-induced oxidative stress while preserving antioxidant defense capability in rat skeletal muscles and lung. Eight adult male Sprague-Dawley rats per group were randomly assigned to the resting control, exercise control, resting with IH901 (25, 50, and 100 mg/kg) consumption (R/IH901), or exercise with IH901 (25, 50, and 100 mg/kg) consumption (E/IH901) group. The trained groups ran 35 min 2 days/week for 8 weeks. To analyze the IH901-training interaction, serum biochemical analysis, lipid peroxidation, citrate synthase, protein oxidation, antioxidant and superoxide dismutase in skeletal muscles and lung tissue were measured. Compared to the exercise control group, animals that consumed IH901 had significantly increased exercise endurance times (p < 0.05) and decreased plasma creatine kinase and lactate dehydrogenase levels (p < 0.05), while those in the E/IH901 groups had increased citrate synthase and anti-oxidant enzymes and decreased lipid peroxidation and protein oxidation (p < 0.05). In conclusion, IH901 consumption in aging rats after eccentric exercise has beneficial effects on anti-inflammatory and anti-oxidant activities through down-regulation of pro-inflammatory mediators, lipid peroxidation, and protein oxidation and up-regulation of anti-oxidant enzymes.

Effect of treadmill exercise and Ferula gummosa on myocardial HSP72, vascular function, and antioxidant defenses in spontaneously hypertensive rats

This study evaluates the effect of treadmill exercise and Ferula gummosa (FG) on heat shock protein (HSP72), biomarkers related to vascular function, and oxidant/antioxidant system in the heart tissue of spontaneously hypertensive rats treated with N(ω)-nitro-L-arginine-methyl ester (L-NAME). Fifty adult male Wistar rats are randomly classified into five groups: treadmill exercise, FG, combination of treadmill exercise + FG, L-NAME, and saline. Treadmill exercise was performed between 25 and 64 minutes at the speed of 15-22 m per minute for 8 weeks and five sessions a week. The FG will be fed through gavage with 90 mg/kg dosage. Hypertension was induced by l-NAME (10 mg/kg) for 8 weeks and six sessions a week. Administration of L-NAME for 8 weeks caused significant increase in HSP72, angiotensin-converting enzyme (ACE), and protein carbonyl (PC), and significant decrease in glutathione peroxidase (GPx) and nitric oxide (NO) level, when compared with the saline group. In contrast, both treadmill exercise and/or FG protocols, in particular, the combined protocol, led to the improvement in HSP72 and balance in oxidant/antioxidant process and inhibited vascular dysfunction, when compared with the L-NAME group. Moreover, no significant differences were detected in the HSP72 level between rats in the treadmill exercise and FG groups. These results provide a rationale for an inhibitory role and a cardioprotective effect of lifestyle related to the health in the attenuation of hypertension-induced cardiotoxicity.

Exercise training prevents ecto-nucleotidases alterations in platelets of hypertensive rats

In this study, we investigated the effect of 6 weeks of swimming training on the ecto-nucleotidase activities and platelet aggregation from rats that developed hypertension in response to oral administration of L-NAME. The rats were divided into four groups: control (n = 10), exercise (n = 10), L-NAME (n = 10), and exercise L-NAME (n = 10). The animals were trained five times per week in an adapted swimming system for 60 min with a gradual increase of the workload up to 5 % of animal's body weight. The results showed an increase in ATP, ADP, AMP, and adenosine hydrolysis, indicating an augment in NTPDase (from 35.3 ± 8.1 to 53.0 ± 15.1 nmol Pi/min/mg protein for ATP; and from 21.7 ± 7.0 to 46.4 ± 15.6 nmol Pi/min/mg protein for ADP as substrate), ecto-5'-nucleotidase (from 8.0 ± 5.7 to 28.1 ± 6.9 nmol Pi/min/mg protein), and ADA (from 0.8 ± 0.5 to 3.9 ± 0.8 U/L) activities in platelets from L-NAME-treated rats when compared to other groups (p < 0.05). A significant augment on platelet aggregation in L-NAME group was also observed. Exercise training was efficient in preventing these alterations in the exercise L-NAME group, besides showing a significant hypotensive effect. In conclusion, our results clearly indicated a protector action of moderate intensity exercise on nucleotides and nucleoside hydrolysis and on platelet aggregation, which highlights the exercise training effect to avoid hypertension complications related to ecto-nucleotidase activities.

Lisinopril attenuates renal oxidative injury in L-NAME-induced hypertensive rats

Hypertension and related oxidative stress are involved in the pathogenesis of any renal diseases. Angiotensin-converting enzyme inhibitors have multi-directional renoprotective effects. In this study, we aimed to investigate whether lisinopril treatment has any biochemical alterations on renal tissue in L-NAME (Nε-nitro-L-arginine methyl ester) induced hypertension model. Twenty-eight Sprague-Dawley rats were included in this study and divided into four equal groups (n = 7): control group, L-NAME treated group (75 mg/kg/day), L-NAME plus lisinopril treated group and only lisinopril treated group (10 mg/kg/day). L-NAME and lisinopril were continued for 6 weeks. Systolic blood pressures were measured by using tail cuff method. In biochemical analysis, malondialdehyde (MDA, an index of lipid peroxidation) levels, the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in renal tissues were used as markers of oxidative stress-induced renal impairment. Microalbumin and N-acetyl-β-D-glucosaminidase (NAG) in urine were determined as markers of renal tubular damage related to hypertension. Chronic L-NAME administration resulted in a significant depletion of serum nitric oxide (NO). When compared with control group, serum creatinine, microalbumin, urine NAG, renal tissue MDA level, and CAT activities were significantly high, while renal tissue SOD and GSH-Px activities low in L-NAME group. In the L-NAME plus lisinopril treated group, serum creatinine, microalbumin and urine NAG, renal MDA level and CAT activity decreased, whereas SOD, GSH-Px activities in renal tissue and serum NO levels were increased. Thus, lisinopril treatment reversed these effects. There were not any significant difference between L-NAME plus lisinopril treated group and control group concerning serum creatinine, renal tissue MDA level and SOD, GSH-Px, CAT activities. These results suggest that lisinopril could diminish biochemical alterations in L: -NAME induced hypertensive renal damage that occurs by oxidative stress.

β-Escin sodium inhibits inducible nitric oxide synthase expression via downregulation of the JAK/STAT pathway in A549 cells

β-escin, a triterpene saponin, is one of the major active compounds extracted from horse chestnut (Aesculus hippocastanum) seed. Previous work has found that β-escin sodium has antiinflammatory and antitumor effects. In the present study, we investigated its effect on cell proliferation and inducible nitric-oxide synthase (iNOS) expression in human lung carcinoma A549 cells. β-escin sodium (5-40 µg/mL) inhibited cytokine mixture (CM)-induced nitric oxide (NO) production in A549 cells by reducing the expression of iNOS. β-escin sodium suppressed phosphorylation and nuclear translocation of STAT1 (Tyr701) and STAT3 (Tyr705) induced by CM but did not affect the activation of c-Jun and NF-κB. β-escin sodium inhibited the activation of protein tyrosine kinase JAK2. Pervanadate treatment reversed the β-escin sodium-induced downregulation of STAT3 and STAT1. β-escin sodium treatment enhanced an activating phosphorylation of the phosphatase SHP2. Small interfering RNA-mediated knockdown of SHP2 inhibited β-escin sodium-induced phospho-STAT dephosphorylation. Moreover β-escin sodium reduced the activation of p38 MAPK. Finally, β-escin sodium inhibited the proliferation of A549 cells, did not change the cell membrane's permeability, nuclear morphology and size and the mitochondria's transmembrane potential of A549 cells. Taken together, these results demonstrate that β-escin sodium could downregulate iNOS expression through inhibiting JAK/STAT signaling and p38 MAPK activation in A549 cells. β-escin sodium has a marked antiproliferative effect on A549 cells at least in part by inhibiting the JAK/STAT signaling pathway, but not by a cytotoxic effect. β-escin sodium would be useful as a chemopreventive agent or a therapeutic against inflammatory-associated tumor. © 2011 Wiley Periodicals, Inc.

Vulnerability of the mid aged rat myocardium to the age-induced oxidative stress: Influence of exercise training on antioxidant defense system

This study investigated the onset of age-related changes in the myocardial antioxidant defense system (ADS) and the vulnerability of the myocardium to oxidative stress following exercise training. Few studies have investigated the influence of the most prevalent life-prolonging strategy physical exercise, on the age-dependent alterations in the myocardial antioxidant enzyme system of female rats at mid age and to determine whether exercise-induced ADS could attenuate lipid peroxidation. Two age groups young (3 months old) and mid age (12 months old) Wistar strain female albino rats were given chronic exercise training for a period of 12 weeks. We found a striking decrease (p < 0.01) in the activity levels of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) in the myocardium of mid aged rats when compared to young rats by 36, 50 and 29%, respectively, suggesting the onset of age-dependent decrease in the myocardial ADS. A similar age-related decrease (p < 0.01) was observed in the reduced glutathione (GSH) content (36%). Despite the reduction in ADS, lipid peroxidation (LPO) (20%) was also decreased. In contrast, exercise training significantly elevated (p < 0.01) these antioxidant enzyme activities and the content of GSH. The increase in SOD and CAT activities were more pronounced in the mid aged rats when compared to younger rats, but increased the level of lipid peroxidation to higher levels in the mid-age group following the training regimen. The findings of the present study suggest that, although the activity levels of the myocardial antioxidant enzymes were elevated with the 12 weeks of exercise training, the changes were not sufficient enough in attenuating oxidative stress in the myocardium of female rats during this short period of exercise training.

Down regulation of aortic nitric oxide and antioxidant systems in chronic alcohol-induced hypertension in rats

The aim of this study was to investigate the relationship between chronic ethanol-induced increase in blood pressure (BP) and alterations in the aortic nitric oxide (NO) and the antioxidant systems in rats. Male Fisher rats (200-250 g) were divided into two groups of six animals each and treated as follows: 1) control (5% sucrose, orally) daily for 12 weeks and 2) 20% ethanol (4 g/kg, orally) daily for 12 weeks. The BP (systolic, diastolic and mean) was recorded every week through tail-cuff method. The animals were sacrificed 12 weeks after treatments and thoracic aorta was collected and analysed. The results show that systolic, diastolic and mean BP was significantly elevated 12 weeks after ethanol ingestion in rats compared to control. The endothelial nitric oxide synthase (eNOS) and vascular endothelial growth factor (VEGF) expressions were down-regulated (50-55% of control) leading to depletion of aortic NO levels (69% of control) in ethanol treated rats compared to control. The ratio of reduced to oxidized glutathione (GSH/GSSG) was significantly depleted (58% of control) in the aorta of ethanol-treated rats compared to control. The decrease in aortic GSH/GSSG ratio was good correlated with increase in BP (r = 0.69). The antioxidant enzymes: copper/zinc-superoxide dismutase (CuZn-SOD) and manganese (Mn)-SOD, catalase (CAT) and glutathione peroxidase (GSH-Px) activities were significantly depressed (36-53% of control) in the aorta of ethanol-treated rats compared to control. The study concluded that chronic ethanol ingestion induces hypertension which relates to the vascular endothelial dysfunction on account of the down-regulation of aortic endothelial antioxidants and NO generating system in rats.

Myocardial antioxidant status and oxidative stress after combined action of exercise training and ethanol in two different age groups of male albino rats

The interaction of exercise training and ethanol on the myocardial antioxidant enzymes and the oxidative stress markers was investigated in the Wistar strain male albino rats. We also tested the interactive effects of exercise training and ethanol on the age-associated free radical production and antioxidant defense system. We found a significant decrease (p<0.05) in the activity levels of superoxide dismutase (SOD) and catalase (CAT) in the myocardium of old rats when compared to young rats by 26% and 58%, respectively, suggesting the onset of age-dependent decrease in the myocardial antioxidant enzyme system. In contrast to the decreased antioxidant enzyme activity, xanthine oxidase (XOD) and lipid peroxidation (LPO) levels were elevated, suggesting the age-induced oxidative stress. Exercise training significantly (p < 0.05) elevated the activities of SOD, CAT, XOD and LPO levels in both the age groups of animals. Ethanol consumption significantly lowered the SOD and CAT activities in both the age groups, whereas a significant increase was observed in the XOD and LPO levels. In contrast, the combination of exercise training plus ethanol lowered XOD and LPO levels in both the age groups of rats compared to ethanol treated rats. A significant (p < 0.05) increase in the activities of SOD and CAT was reported in the rats treated with the combination of exercise training plus ethanol. This increase was more pronounced in the younger rats than the older rats. The findings of the present investigation on the potential role of antioxidant enzymes to counter the ethanol-induced pro-oxidants showed an increase with the interaction of exercise training. With age, a decrease in the antioxidant enzyme capacity was observed. This reveals that the old age rats were more affected to the pro-oxidants when compared to the young age rats. In conclusion it is demonstrated that two months treadmill endurance exercise training is beneficial to both young and old rats in improving antioxidant defense to challenge the oxidative stress in the myocardial tissue and thereby successfully countering the free radical production due to ethanol intoxication.

Physiological basis for effect of physical conditioning on chronic ethanol-induced hypertension in a rat model

The study aim was to investigate the interaction of physical conditioning and chronic ethanol ingestion on blood pressure (BP), heart rate (HR), nitric oxide (NO) and oxidants/antioxidants balance in the plasma of rats. Male Fisher rats were divided into four groups of seven animals each and treated as follows: (1) Control (5% sucrose, orally) daily for 12 weeks; (2) ethanol (4 g kg(-1), orally) daily for 12 weeks; (3) exercise training on treadmill plus sucrose daily for 12 weeks and (4) exercise training on treadmill followed by ethanol (4 g kg(-1), orally) daily for 12 weeks. The body weight, BP and HR were recorded every week. The animals were sacrificed under ether anesthesia after 12 weeks, blood collected in heparinzed vials, plasma isolated and analyzed. The results show that exercise training significantly lowered the weight gain 6-12 weeks in ethanol treated rats compared to ethanol alone or control rats. The mean arterial BP was significantly elevated 6-12 weeks after ethanol ingestion without significant alterations in HR. Exercise training lowered the BP close to the normal control values in ethanol fed rats. Ethanol significantly decreased the plasma NO levels, reduced to oxidized glutathione ratio (GSH/GSSG) and antioxidant enzymes-superoxide dismutase (CuZn-SOD, and Mn-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities while plasma NADPH oxidase activity and malondialdehyde (MDA) levels were significantly elevated compared to control. Exercise training significantly restored the depletion of plasma NO levels, GSH/GSSG ratio, and antioxidant enzyme activities and normalized the MDA levels and NADPH oxidase activity in the plasma of ethanol treated rats. The study concluded that physical conditioning attenuates the chronic ethanol-induced hypertension by augmenting the NO bioavailability and reducing the oxidative stress response in the plasma of rats.

Exercise training attenuates cardiovascular adverse remodeling in adult ovariectomized spontaneously hypertensive rats

OBJECTIVE

To study the combined effects of ovariectomy and regular exercise training on hypertension and on cardiac and aortic remodeling in spontaneously hypertensive rats (SHR).

DESIGN

Three-month-old female spontaneously hypertensive rats (SHR) were ovariectomized (ovx) or were left intact (int) and divided in four groups (n = 7): sedentary (sed-ovx), exercise-trained (ex-ovx), sedentary intact (sed-int), and exercise-trained intact (ex-int). The exercise protocol was performed on a motor treadmill for 13 weeks. Blood pressure (BP), left ventricular myocardium and aortic wall were studied by light microscopy and stereology.

RESULTS

Exercise-trained SHR showed a BP reduction of more than 15% compared with the matched sedentary SHR (sed-int: 210 +/- 5 mm Hg, sed-ovx: 225 +/- 4 mm Hg, ex-int: 178 +/- 2 mm Hg, ex-ovx: 180 +/- 3 mm Hg, P < 0.001). Ovariectomy caused adverse cardiac and aortic wall remodeling, including cardiomyocyte hypertrophy, myocardial interstitial reparative fibrosis and vascularization impairment with loss of cardiomyocytes, and aortic tunica media hypertrophy. Exercise training showed beneficial effects, mainly reduced BP, decreased cardiac hypertrophy due to hypertension, and increased myocardial vascularization. Ovariectomy accelerated cardiomyocyte loss in SHR while exercise training offset this process. Exercise training was the main factor influencing the improvement of intramyocardial arteries length density and significantly reduced the aortic wall thickness and increased the density of smooth muscle cell nuclei per tunica media unit area.

CONCLUSIONS

In ovariectomized SHR, exercise training exerts beneficial effects diminishing adverse cardiac and aortic wall remodeling, mainly by reducing interstitial myocardial fibrosis, improving myocardial vascularization, and sustaining the number of cardiomyocytes.

Physical training ameliorates chronic alcohol-induced hypertension and aortic reactivity in rats

AIMS

The aim of this study was to investigate the interactive effect of physical training and chronic ethanol ingestion on changes in blood pressure (BP) and aortic reactivity response in rats.

METHODS

Male Fisher rats were divided into four groups of seven animals each and treated as follows: (i) control (5% sucrose, orally) daily for 12 weeks; (ii) ethanol (4 g kg(-1), orally) daily for 12 weeks; (iii) exercise training on treadmill followed by sucrose daily for 12 weeks; (iv) exercise training on treadmill followed by ethanol daily for 12 weeks. The body weight and BP were recorded every week. The animals were anaesthetized with pentobarbital after 12 weeks; blood and thoracic aorta were isolated and analysed for ethanol and reactivity response using tissue bath technique, respectively.

RESULTS

The data show that exercise training significantly lowered the weight gain 6-12 weeks in ethanol-treated rats compared to ethanol alone or control rats. The systolic and mean BP significantly elevated 6-12 weeks, whereas diastolic BP elevated 8-12 weeks after ethanol ingestion. Exercise training lowered the BP close to the normal control values in ethanol fed rats. Blood ethanol level significantly elevated in ethanol group but decreased in exercise plus alcohol group. Aortic contractile response to phenylephrine in ethanol or control groups was attenuated by training with or without intact endothelium. Ethanol significantly reduced the aortic relaxation response to acetylcholine whereas training enhanced the relaxation response with intact endothelium. The relaxation responses to adenosine and sodium nitroprusside in the aortic ring segments of rats with or without endothelium were decreased in ethanol group which were attenuated by exercise training.

CONCLUSIONS

Physical training attenuates the chronic ethanol-induced hypertension via reduction of body weight, clearance of ethanol, and augmentation of the aortic endothelial relaxation response in rats.

Different antioxidants status, total antioxidant power and free radicals in essential hypertension

Hypertension is a multi-factorial process, prevalent in developed as well as in developing countries. Different antioxidants and free radicals play an important role in cardiovascular system. In present study, total antioxidant power in terms of FRAP (ferric reducing activity of plasma), free radicals and different antioxidants have been studied in essential hypertensives (n = 50) and normal subjects (n = 50). Levels of total cholesterol, low-density lipids-cholesterol, malonialdehyde, very low-density lipids (VLDL), uric acid, plasma homocysteine and low-density lipids (LDL), were significantly higher in hypertensives as compared to normotensive. HDL-cholesterol, SOD, GPx, reduced glutahione, total glutathione, oxidized glutathione, total thiols, protein thiols, non protein thiols, RNI, total antioxidant power, vitamin A, ascorbic acid and glutahione-S-transferase (GST) were decreased significantly in normotensive. We observed significantly low nitric oxide levels in hypertensive patients. No correlation was observed between severity of disease and plasma nitric oxide levels. There was a significant decrease in plasma FRAP value in essential hypertensives as compared to normotensive controls, which showed a negative correlation with diastolic blood pressure. In conclusion, our study revealed that there was a consistent significant difference between essential hypertensives versus controls with respect to most of the parameters. These complex changes are consistent in the view that essential hypertension is associated with an abnormal level of antioxidant status compared to normal response to oxidative stress or both.

Response of hepatic antioxidant system to exercise training in aging female rat

This study was undertaken to investigate the effect of exercise training on aging in the hepatic oxidative status and antioxidant defense of female albino rat. Two age groups of 3 months and 12 months old Wistar strain female albino rats were given chronic exercise training for a period of 12 weeks. The antioxidant enzyme assays were carried out by the standard methods. Lower (P<0.01) activities of the antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR) by 21%, 44% and 63% respectively was observed in the older rats when compared to younger rats. Also, glutathione (GSH) levels were 42% lower (P<0.01) in older than younger animals. Exercise training to the 12 months aged rats significantly (P<0.01) elevated these antioxidant enzyme activities and GSH content, when compared to older control rats. These levels are almost equal to the values observed in the younger control rats. The levels of lipid peroxidation end product, malondialdehyde (MDA) the major indicator of oxidative stress, was found to increase with age (11%) and exercise training caused further elevation (28% of control). The present findings imply that the reactive oxygen species that are generated due to aging process were detoxified by the exercise induced antioxidant system in the liver tissue. These findings are also in agreement with similar changes in male animals, which clearly envisage no gender difference in the amelioration of the antioxidant enzyme system in older age due to exercise. In conclusion, it can be stated that twelve weeks treadmill exercise training has beneficial effect in improving antioxidant defense capacity by augmenting SOD, CAT and GR activities and GSH levels of older rats, thereby preventing oxidative damage to the liver tissue.

Physical conditioning modulates rat cardiac vascular endothelial growth factor gene expression in nitric oxide-deficient hypertension

Many individuals with cardiac diseases undergo periodic physical conditioning with or without medication to improve cardiovascular health. Therefore, this study investigated the interaction of physical training and chronic nitric oxide synthase (NOS) inhibitor (nitro-L-arginine methyl ester, L-NAME) treatment on blood pressure (BP), cardiac vascular endothelial factor (VEGF) gene expression, and nitric oxide (NO) systems in rats. Fisher 344 rats were divided into four groups and treated as follows: (1) sedentary control, (2) exercise training (ET) for 8 weeks, (3) L-NAME (10mg/kg, s.c. for 8 weeks), and (4) ET+L-NAME. BP was monitored with tail-cuff method. The animals were sacrificed 24h after last treatments and hearts were isolated and analyzed. Physical conditioning significantly increased respiratory exchange ratio, cardiac NO levels, NOS activity, endothelial eNOS, and inducible iNOS protein expression as well as VEGF gene expression. Training also caused depletion of cardiac malondialdehyde (MDA) levels indicating the beneficial effects of the training. Chronic L-NAME administration resulted in a depletion of cardiac NO level, NOS activity, and eNOS, nNOS, and iNOS protein expressions, as well as VEGF gene expression (2-fold increase in VEGF mRNA). Chronic L-NAME administration also enhanced cardiac MDA levels indicating cardiac oxidative injury. These biochemical changes were accompanied by increases in BP after L-NAME administration. Interaction of training and NOS inhibitor treatment resulted in normalization of BP and up-regulation of cardiac VEGF gene expression. The data suggest that physical conditioning attenuated the oxidative injury caused by chronic NOS inhibition by up-regulating the cardiac VEGF and NO levels and lowering the BP in rats.

Arteriolar Endothelial Dysfunction Is Restored in Ischaemic Muscles by Chronic Electrical Stimulation

Chronic intermittent electrical stimulation (15 min on, 85 min off, seven times per day) eliminated endothelial dysfunction of pre-capillary arterioles in ischaemic rat ankle flexor muscles. Responses to acetylcholine were restored from constriction to dilation, and the reduced dilation to bradykinin was corrected by 1 week of stimulation. Administration of the NOS inhibitor N(omega)-nitro-L-arginine for 1 week impaired arteriolar reactivity in a similar way to ischaemia, and dilator function was likewise restored by chronic stimulation. This suggests that nitric oxide production in the microcirculation is depressed by chronic ischaemia and that chronic electrical stimulation can specifically reverse this deficit. Stimulation applied to ischaemic muscles for 2 weeks also increased the numbers of microvessels immunostained for alpha-smooth muscle actin and the numbers of eNOS-positive microvessels and capillaries. These findings help to elucidate the mechanism of the beneficial effect of exercise in the treatment of peripheral vascular diseases by showing that muscle activity can improve both function and structural capacity of the microvasculature.

Green tea inhibits human inducible nitric-oxide synthase expression by down-regulating signal transducer and activator of transcription-1alpha activation

Green tea has been reported to show anti-inflammatory properties because of its inhibitory effects on the expression of several pro-inflammatory genes. Because the inducible nitricoxide synthase (iNOS) plays an important role in chronic inflammatory diseases, we have focused our attention on the regulation of iNOS expression by green tea in two different human epithelial cell lines, alveolar A549/8 and colon DLD-1 cells. With the use of electrophoretic mobility shift assays, we found a green tea-mediated down-regulation of the DNA binding activity of the transcription factor signal transducer and activator of transcription-1alpha (STAT-1alpha), but not of nuclear factor-kappaB. This down-regulation of the STAT-1alpha DNA binding was shown to result from reduced tyrosine phosphorylation of the STAT-1alpha protein and not from antioxidative effects of the green tea extract. Green tea extract inhibited human iNOS expression in a concentration-dependent manner, quantified in terms of iNOS mRNA, iNOS protein, and nitric oxide production in both cell lines. This inhibitory effect of green tea resulted from transcriptional inhibition as shown in reporter gene experiments. These data suggest that green tea extracts may be promising at least as an auxiliary anti-inflammatory principle in chronic inflammatory diseases.

Interaction of regular exercise and chronic nitroglycerin treatment on blood pressure and rat aortic antioxidants

Many cardiac patients undergo exercise conditioning with or without medication. Therefore, we investigated the interaction of exercise training and chronic nitroglycerin treatment on blood pressure (BP), aortic nitric oxide (NO), oxidants and antioxidants in rats. Fisher 344 rats were divided into four groups and treated as follows: (1) sedentary control, (2) exercise training (ET) for 8 weeks, (3) nitroglycerin (15 mg/kg, s.c. for 8 weeks) and (4) ET+nitroglycerin. BP was monitored with tail-cuff method. The animals were sacrificed 24 h after the last treatments and thoracic aorta was isolated and analyzed. Exercise training on treadmill for 8 weeks significantly increased respiratory exchange ratio (RER), aortic NO levels, and endothelial nitric oxide synthase (eNOS) protein expression. Training significantly enhanced aortic glutathione (GSH), reduced to oxidized glutathione (GSH/GSSG) ratio, copper/zinc-superoxide dismutase (CuZn-SOD), Mn-SOD, catalase (CAT), glutathione peroxidase (GSH-Px) glutathione disulfide reductase (GR) activities and protein expressions. Training significantly depleted aortic malondialdehyde (MDA) and protein carbonyls without change in BP. Nitroglycerin administration for 8 weeks significantly increased aortic NO levels and eNOS protein expression. Nitroglycerin significantly enhanced aortic Mn-SOD, CAT, GR and glutathione-S-transferase (GST) activities and protein expressions with decreased MDA levels, protein carbonyls and BP. Interaction of training and nitroglycerin treatment significantly increased aortic NO levels, eNOS protein expression, GSH/GSSG ratio, antioxidant enzymes and normalized BP. The data suggest that the interaction of training and nitroglycerin maintained BP by up-regulating the aortic NO and antioxidants and reducing the oxidative stress in rats.

Interaction of exercise training and chronic NOS inhibition on blood pressure, heart rate, NO and antioxidants in plasma of rats

Many individuals with cardiovascular diseases undergo periodic exercise conditioning with or without medication. Therefore, the purpose of this study was to examine the effect of exercise training on BP and HR under the condition of NOS inhibition and to clarify the mechanism of the effect in regard to oxidative stress, antioxidant enzyme activity, and NO production in the plasma of the rat. Fisher 344 rats were divided into four groups: (1) sedentary control, (2) exercise training for 8 weeks, (3) nitro-L-arginine methyl ester (L-NAME) (10mg/kg, s.c. for 8 weeks) and (4) ET + L-NAME. Blood pressure (BP) and heart rate (HR) were monitored weekly for 8 weeks. The animals were sacrificed 24h after last treatments, plasma isolated and analyzed. The results show that exercise conditioning resulted in enhanced NO production (120% of control), GSH levels (110% of control), GSH/GSSG ratio (124% of control) and the up-regulation of catalase (CAT) (225% of control), glutathione peroxidase (GSH-Px) (161% of control), glutathione reductase (GR) (142% of control) and glutathione-S-transferase (GST) (189% of control) and depression of malondialdehyde (MDA) (90% of control) and lactate (75% of control) in plasma of the rat. These biochemical changes were accompanied by no significant change in BP but slight increase in HR. Chronic L-NAME administration resulted in depression of NO (84% of control), GSH (90% of control), GSH/GSSG ratio (76% of control), the down-regulation of superoxide dismutase (SOD) (67% of control), GST (74% of control), and GR (90% of control). Plasma CAT and GSH-Px activities, MDA and lactate levels were significantly increased in L-NAME treated rats. The biochemical changes were accompanied by increase in blood pressure and heart rate. Interaction of exercise training and chronic NOS inhibitor treatment resulted in normalization of plasma NO levels, GSH/GSSG ratio, SOD and GST activities, and the up-regulation of, CAT, GSH-Px, and GR activities. The interaction resulted in depletion of plasma MDA levels compared to L-NAME treated group. The biochemical changes were accompanied by decrease in BP and HR compared to L-NAME treated group. The data suggest that the exercise training attenuated the oxidative injury caused by NOS inhibitor by increasing the plasma NO levels, GSH/GSSG ratio and up-regulating the antioxidant enzyme and lowering the BP and HR in the rat.

Anti-inflammatory actions of St. John's wort: inhibition of human inducible nitric-oxide synthase expression by down-regulating signal transducer and activator of transcription-1alpha (STAT-1alpha) activation

St. John's wort (SJW) has been described to show anti-inflammatory properties due to its inhibitory effects on the expression of pro-inflammatory genes like cyclooxygenase-2, interleukin-6, and inducible nitric-oxide synthase (iNOS). Since iNOS plays a critical role in chronic inflammatory diseases, we have focused our attention on the regulation of iNOS expression by SJW in two different human epithelial cell lines, alveolar A549/8 and colon DLD-1 cells. SJW extract concentration dependently inhibited human iNOS expression evaluated by measuring the amounts of iNOS mRNA, iNOS protein, and NO production in both cell lines. This inhibitory effect resulted from transcriptional inhibition as shown in reporter gene experiments. With electrophoretic mobility shift experiments, we found a SJW-mediated down-regulation of the DNA binding activity of the transcription factor signal transducer and activator of transcription-1alpha (STAT-1alpha), but not of nuclear factor-kappaB. This down-regulation of the STAT-1alpha DNA binding was shown to result from reduced tyrosine phosphorylation of the STAT-1alpha protein. The diminished STAT-1alpha tyrosine phosphorylation resulted from SJW-mediated reduction of Janus kinase 2 activity. These data suggest that extracts from SJW may be a promising anti-inflammatory principle in chronic inflammatory diseases.

Attenuation of homocysteine-induced endothelial dysfunction by exercise training

Hyperhomocysteinemia is an independent risk factor for the development of cardiovascular disease. Exposure of endothelial cells to elevated levels of homocysteine (HCY) results in decreased availability of nitric oxide (NO) and impaired vascular function, both of which are early events in atherogenesis. Exercise training improves vascular function by increasing endothelial NO production secondary to an increase in the enzyme responsible for its synthesis, endothelial nitric oxide synthase (eNOS). We hypothesized that exercise training would increase endothelial NO production, which would attenuate the endothelial dysfunction associated with HCY exposure. Rats were randomly assigned to either sedentary (SED) or exercise (EX) groups. The exercise regimen consisted of treadmill running at 20-25 m/min, 15% grade, 30 min/day, 5 day/week for 6 weeks. Aortic rings obtained from SED and EX trained rats were incubated with 2 mM HCY for 120 min, then exposed to norepinephrine (NE 100 nM) to induce vasoconstriction. Once a stable contraction plateau was achieved, rings were exposed to increasing concentrations of the receptor-mediated endothelium-dependent vasodilator acetylcholine (ACh; 0.1, 1, 10, 100 nM). This procedure was repeated with the non-receptor-mediated endothelium-dependent vasodilator A-23187 (0.1, 1, 10, 100 nM), and the endothelium-independent vasodilator, NaNO(2) (0.1, 1, 10, 100 muM). In addition, eNOS protein content and eNOS enzyme activity were determined. Aortic rings obtained from exercise trained rats demonstrated significantly (P<0.05) greater relaxation to both ACh and A-23187 in comparison to aortic rings obtained from SED rats following exposure to HCY. Additionally, exercise training increased aortic eNOS protein content and activity. Our data demonstrate that exercise training improves endothelium-dependent vasorelaxation following HCY exposure and this may be due, at least in part, to elevated levels of eNOS protein and an increase in eNOS activity. These results suggest the possible role exercise may play in attenuating the endothelial dysfunction associated with hyperhomocysteinemia.

Interaction of physical training and chronic nitroglycerin treatment on blood pressure and plasma oxidant/antioxidant systems in rats

Many individuals with cardiovascular diseases undergo periodic physical conditioning with or without medication. Therefore, this study investigated the interaction of exercise training and chronic nitroglycerin treatment on blood pressure (BP) and alterations in nitric oxide (NO), glutathione (GSH), antioxidant enzyme activities and lipid peroxidation in rats. Fisher 344 rats were divided into four groups: (1) sedentary control, (2) exercise training for 8 weeks, (3) nitroglycerin (15 mg/kg, s.c. for 8 weeks) and (4) training + nitroglycerin for 8 weeks. BP, heart rate (HR) and respiratory exchange ratio (RER) were monitored weekly for 8 weeks using tail-cuff method and oxygen/carbon dioxide analyzer, respectively. The animals were sacrificed 24 h after last treatments and plasma isolated and analyzed using HPLC, ELISA and UV-VIS spectrophotometric techniques. The results show that exercise conditioning significantly enhanced NO production (p < 0.001), GSH levels (p < 0.001), GSH/GSSG ratio (p < 0.05) and the up-regulation of the activities of catalase (CAT) (p < 0.05), glutathione peroxidase (GSH-Px) (p < 0.001), and glutathione reductase (GR) (p < 0.05), and depression of lactate levels (p < 0.001) in the plasma of the rat. These biochemical changes were accompanied by a significant increase in RER (p < 0.001) without a significant change in BP and HR. Chronic nitroglycerin administration significantly increased NO levels (p < 0.05), GSH levels (p < 0.001), superoxide dismutase (SOD) activity (p < 0.05), GST activity (p < 0.05), and decreased MDA levels (p < 0.05). These biochemical changes were accompanied by a significant decrease in BP (p < 0.05) and without any significant changes in HR and RER. Interaction of exercise training and chronic nitroglycerin treatment resulted in normalization of plasma NO, MDA, lactate levels, and CAT activity. The combination of exercise and nitroglycerin significantly enhanced GSH levels (p < 0.05), and the up-regulation of SOD (p < 0.001), GSH-Px (p < 0.05), GR (p < 0.05) and GST (p < 0.001) activities. These biochemical changes were accompanied by normalization of BP and a significant increased in RER (p < 0.001). The data suggest that the interaction of physical training and chronic nitroglycerin treatment resulted in the maintenance of BP and the up-regulation of plasma antioxidant enzyme activities and GSH levels in the rat.