The effects of chronic exposure to ethanol and cigarette smoke on the level of reduced glutathione and malondialdehyde in rat kidney

Passive smoking and urinary oxidative biomarkers: A pilot study of healthy travelers from Los Angeles to Beijing

There is a great heterogeneity in smoking prevalence and tobacco control policy across different countries. However, it is unknown whether this heterogeneity could cause increased passive smoking and adverse health effects among international travelers. In this pilot study, we collected 190 urine samples from 26 Los Angeles residents before (LA-before), during (Beijing), and after (LA-after) a 10-week visit to Beijing to measure biomarkers of passive smoking (cotinine), exposure to polycyclic aromatic hydrocarbons (OH-PAHs), and oxidative stress (malondialdehyde, 8-isoprostane, and uric acid). The geometric mean concentrations of urinary cotinine were 0.14, 1.52, and 0.22 μg/g creatinine in LA-before, Beijing, and LA-after, respectively. Likewise, OH-PAH levels were significantly higher in Beijing as compared to LA-before or LA-after, in association with the urinary cotinine levels. One-fold increase in urinary cotinine levels was associated with 10.1% (95% CI: 5.53-14.8%), 8.75% (95% CI: 2.33-15.6%), and 25.4% (95%CI: 13.1-39.1%) increases in urinary levels of malondialdehyde, 8-isoprotane, and uric acid, respectively. OH-PAHs mediated 9.1-23.3% of the pro-oxidative effects associated with passive smoking. Taken together, our findings indicate that traveling to a city with higher smoking prevalence may increase passive smoking exposure, in association with pro-oxidative effects partially mediated by PAHs.

The modulatory effect of taurine on benzo (a) pyrene-induced hepatorenal toxicity

Toxicities linked with Benzo (a) pyrene B[a]P exposure, particularly in liver and kidney have been reported in both animals and humans. Taurine (2-aminoethane sulfonic acid) is an intracellular β-amino acid reported to elicit hepatorenal protective functions. However, the modulatory effect of taurine on hepatorenal toxicity associated with exposure to B[a]P has not been reported. This study evaluated the effects of taurine on the hepatorenal toxicities induced in cohorts of rats exposed to B[a]P. Experimental rats were treated as follows: B[a]P (10 mg/kg); co-treated cohorts -B[a]P (10 mg/kg) plus taurine (100 or 200 mg/kg) for 4 successive weeks. Results show that co-dosing with taurine significantly (P < 0.05) improved B[a]P-induced distortion of oxidative stress markers (catalase, superoxide dismutase, glutathione S-transferase, glutathione peroxidase, total sulphydryl, reduced glutathione, lipid peroxidation and xanthine oxidase), renal function (urea and creatinine) and liver function marker enzymes (alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase and gamma glutamyl transferase). Moreover, taurine effectively mitigated increase in myeloperoxidase activity, levels of reactive oxygen and nitrogen species, nitric oxide and interleukin-1β in kidney and liver of rats treated with B[a]P. In conclusion, taurine modulates hepatorenal toxicity in B[a]P-exposed rats by suppressing hepatic and renal damage indices, oxidative injury and inflammatory stress.

Short-Term Cigarette Smoking in Rats Impairs Physical Capacity and Induces Cardiac Remodeling

Despite the strong evidence on the cardiac and renal damages after chronic exposure to cigarette smoke, there is a paucity of data on its short-term effects. The study evaluated the short-term effects of cigarette smoking on left ventricular (LV) remodeling, in vitro myocardial and renal function. Female Wistar rats were randomized to control (C) and cigarette smoking rats for eight weeks. Physical capacity was assessed using an adapted model of exhaustive swim; left ventricle (LV) morphology and function were also evaluated. Renal function was assessed by creatinine clearance and urine protein. The in vitro myocardial performance was analyzed in isolated papillary muscles. Rats exhibited reduced physical capacity after short-term cigarette smoking. Although there was no change on LV function, reduced chamber diameter was found in the smoking group associated with an increased LV wall thickness. There was augmented cardiac mass compared to C that was confirmed by increased cardiomyocyte nucleus volume, but in vitro myocardial performance and renal function were unchanged. A short-term cigarette smoking induces cardiac remodeling without abnormalities in function. The smoking group still preserved renal function and in vitro myocardial performance. However, the reduced physical capacity may suggest an impairment of the cardiac reserve.

MitoQ supplementation prevent long-term impact of maternal smoking on renal development, oxidative stress and mitochondrial density in male mice offspring

To investigate the effect of maternal MitoQ treatment on renal disorders caused by maternal cigarette smoke exposure (SE). We have demonstrated that maternal SE during pregnancy increases the risk of developing chronic kidney disease (CKD) in adult offspring. Mitochondrial oxidative damage contributes to the adverse effects of maternal smoking on renal disorders. MitoQ is a mitochondria-targeted antioxidant that has been shown to protect against oxidative damage-related pathologies in many diseases. Female Balb/c mice (8 weeks) were divided into Sham (exposed to air), SE (exposed to cigarette smoke) and SEMQ (exposed to cigarette smoke with MitoQ supplemented from mating) groups. Kidneys from the mothers were collected when the pups weaned and those from the offspring were collected at 13 weeks. Maternal MitoQ supplementation during gestation and lactation significantly reversed the adverse impact of maternal SE on offspring’s body weight, kidney mass and renal pathology. MitoQ administration also significantly reversed the impact of SE on the renal cellular mitochondrial density and renal total reactive oxygen species in both the mothers and their offspring in adulthood. Our results suggested that MitoQ supplementation can mitigate the adverse impact of maternal SE on offspring’s renal pathology, renal oxidative stress and mitochondrial density in mice offspring.

Protective potency of Meristotropis xanthioides against nephrotoxicity in a rat model along with its antioxidant and antibacterial activities

OBJECTIVE

To investigate nephroprotective potential of Meristotropis xanthioides (M. xanthioides) extract against ethanol-induced nephrotoxicity in Wistar rats, and also its total phenolics content, antioxidant and antibacterial activities.

METHODS

Total phenol and flavonoid amounts of the leaf and stem extracts were determined by Folin-Ciocalteu and aluminum chloride reagents, respectively. Antioxidant and antibacterial activities of the extracts were investigated by 2,2-diphenyl-1-picrylhydrazyl radical scavenging and disc diffusion methods, respectively. In addition, protective potential of the leaf extract against ethanol-induced nephrotoxicity was studied by histological and biochemical analyses.

RESULTS

Obtained results indicated high total phenol [(10.26 ± 0.46) mg GAE/g of dry extract] and flavonoid [(3.63 ± 0.62) mg QE/g of dry extract] amounts in the leaf extract. The leaf and stem extracts possessed stronger antioxidant activity [IC₅₀: (0.119 ± 0.006) mg/mL and IC₅₀: (0.133 ± 0.009 mg/mL)] than that of ascorbic acid [IC₅₀: (0.142 ± 0.002) mg/mL]. Also, the extracts showed good antibacterial activity against the most of bacteria taken in this research, especially Gram-positive ones. Histological examinations revealed tissue injury in the kidney of rats treated with ethanol. Results from biochemical assays showed reduction in total protein content and also in superoxide dismutase activity. In addition, remarkable increased levels (P < 0.05) of H₂O₂ and malondialdehyde were found in ethanol-treated rats in comparison to control group. However, these injuries were significantly improved in rats treated by M. xanthioides leaf extract.

CONCLUSIONS

Results from present study demonstrates strong pharmaceutical potential of M. xanthioides extract to apply as a new drug supplement.

Protective effects of N-acetylcysteine on peroxidative changes of the fetal rat lungs whose mothers were exposed to cigarette smoke

Background: This experimental study investigated the protective effects of N-acetylcysteine (NAC) on peroxidative changes in fetal lungs in the offspring of rats exposed to cigarette smoke. Methods: Thirty fetal rats used for analysis, were divided into three groups as follows: control group (n = 10), whose mothers were exposed to fresh air; group I (n=10), whose mothers were exposed to cigarette smoke; and group II (n=10), whose mothers were exposed to cigarette smoke and given 10 mg/kg per day NAC. In groups I and II, smoke exposure was started 4 weeks before the pregnancy, and continued to the 14th day of pregnancy, and in Group II, NAC was administered intraperitoneally for 14 days. The mothers and their fetuses were decapitated on the 14th day of pregnancy. Malondialdehyde (MDA) and glutathione (GSH) levels were determined in the lung tissues of fetuses to determine the oxidant-antioxidant balance. Results: While tissue MDA levels in Group I were found significantly higher than the control group (129.7±65.4 versus 63.4±15.4 nmol/100 mg protein, P <0.05), GSH levels were significantly lower (17.1±7.3 versus 45.4±8.1 nmol/mg protein, P <0.01). Furthermore, in Group II, MDA levels were significantly lower (56.9± 20.6 versus 129.7±65.4 nmol/100 mg protein, P <0.05), and GSH levels were significantly higher (34.57±10.7 versus 17.1±7.3 nmol/mg protein, P <0.0001) when compared with Group I. No statistically significant difference was found in tissue MDA and GSH levels between Group II and the control group (P >0.05). Conclusions: These results suggest that smoke exposure during pregnancy causes oxidative damage in fetal lungs. This smoke-induced damage might be prevented by NAC. Human & Experimental Toxicology (2007) 26, 99-103

Effects of melatonin and vitamin C on cigarette smoke–induced damage in the kidney

This study was carried out to investigate smoke-induced structural and biochemical changes and protective effects of co-administered melatonin and vitamin C in the kidney. Twenty-four Wistar adult female rats were used in this study. Animals were divided into four groups. The first group rats were used as control. The second group of rats inhaled cigarette smoke. Smile smoke inhaling third and fourth group rats received melatonin and vitamin C, respectively. At the end of experimental study, kidney tissues and blood samples were taken under ether anesthesia. Tissues were prepared and examined by light microscopy. Malondialdehyde and glutathione levels and catalase activity were determined. By light microscopic observation, a decrease of Bowman space of some renal corpuscles, foamy-like tubules, dilatation and congestion of the peritubuler vessels, and atrophy of the some renal corpuscles were observed in group II. In groups III and IV melatonin and vitamin C relatively protected the kidney tissue against smoke intoxication. Biochemical examination showed that malondialdehyde and glutathione levels and catalase activity in group II were higher than in group I. Melatonin and vitamin C injection to group III and IV caused a decrease in malondialdehyde and glutathione levels. Catalase activity did not change in these groups. We have shown that cigarette smoke inhalation caused structural changes in the kidney. However, melatonin and vitamin C administration produced in some degree protection against smoke-induced damage.

Protective role of CYP2E1 inhibitor diallyl disulfide (DADS) on alcohol-induced malondialdehyde-deoxyguanosine (M1dG) adduct formation

BACKGROUND

Alcohol use disorders are often associated with lung disease. Alcohol exposure leads to the production of reactive oxygen species, lipid peroxidation, and formation of malondialdehyde (MDA) as well as to induce the expression of cytochrome p450 2E1 (CYP2E1). Likewise, cigarette smoking can lead to lung lipid peroxidation and formation of MDA. MDA can bind to DNA forming MDA-deoxyguanosine (M1dG) adducts, which have been implicated in alcohol-related cancers and cardiovascular disease. Because CYP2E1 regulates MDA production, and our previous studies have shown that alcohol and cigarette smoke can lead to MDA formation, we hypothesized that CYP2E1 would modulate M1dG adduct formation and single-strand DNA damage in alcohol- and cigarette smoke-exposed lung cells and tissue.

METHODS

Normal human bronchial epithelial cells (HBECs) were pretreated with 10 μM diallyl disulfide (DADS) for 1 hour and treated with 80 mM ethanol (EtOH) ± 5% cigarette smoke extract (CSE) for 3 hours for comet assay and 6 hours for CYP2E1, MDA, and M1dG adduct assays. C57BL/6 mice were administered 20% EtOH ad libitum in drinking water for 8 weeks and exposed to whole-body cigarette smoke for 5 weeks. Mice were also fed a CYP2E1 inhibitor, DADS, at 1 μM/g of feed in their daily diet for 7 weeks. Whole lung tissue homogenate was used for CYP2E1, MDA, and M1dG adduct assays.

RESULTS

EtOH exposure significantly increased HBEC olive tail moment. DADS pretreatment of HBECs attenuated this EtOH effect. EtOH also induced MDA and M1dG adduct formation, which was also significantly reduced by DADS treatment. CSE ± EtOH did not enhance these effects. In lung tissue homogenate of 8-week alcohol-fed mice, MDA and M1dG adduct levels were significantly elevated in comparison with control mice and mice fed DADS while consuming alcohol. No increase in MDA and M1dG adduct formation was observed in 5-week cigarette smoke-exposed mice.

CONCLUSIONS

These findings suggest that CYP2E1 plays a pivotal role in alcohol-induced M1dG adducts, and the use of DADS as dietary supplement can reverse the effects of alcohol on M1dG formation.

Chronic nicotine exposure augments renal oxidative stress and injury through transcriptional activation of p66shc

BACKGROUND

Chronic nicotine (Ch-NIC) exposure exacerbates ischemia/reperfusion (I/R)-induced oxidative stress and acute kidney injury (AKI), and mitochondrial production of reactive oxygen species (ROS) in cultured renal proximal tubule cells (RPTCs). Because Ser36-phosphorylated p66shc modulates mitochondrial ROS production and injury of RPTCs, we hypothesized that Ch-NIC exacerbates AKI by increasing stress-induced phosphorylation of p66shc.

METHODS

We first tested whether Ch-NIC augments I/R-AKI-induced expression and phosphorylation of p66shc in vivo. We then examined whether knocking down p66shc, or impairing its Ser36 phosphorylation or binding to cytochrome c, alters the effects of Ch-NIC on oxidative stress (H₂O₂)-induced production of ROS, mitochondrial depolarization and injury in RPTCs in vitro.

RESULTS

We found that Ch-NIC increased the expression of p66shc in the control and ischemic kidneys, but only increased its Ser36 phosphorylation after renal I/R. Knocking down p66shc or impairing phosphorylation of its Ser36 residue, via the S36A mutation (but not the phosphomimetic S36D mutation), blunted Ch-NIC + H2O2-dependent ROS production, mitochondrial depolarization and injury in RPTCs. Additionally, Ch-NIC + H2O2-dependent binding of p66shc to mitochondrial cytochrome c was attenuated by S36A mutation of p66shc, and impairing cytochrome c binding (via W134F mutation) abolished ROS production, mitochondrial depolarization and injury, while ectopic overexpression of p66shc (which mimics Ch-NIC treatment) augmented oxidant injury. We determined that Ch-NIC stimulates the p66shc promoter through p53- and epigenetic modification (promoter hypomethylation).

CONCLUSIONS

Ch-NIC worsens oxidative stress-dependent acute renal injury by increasing expression and consequent oxidative stress-dependent Ser36 phosphorylation of p66shc. Thus, targeting this pathway may have therapeutic relevance in preventing/ameliorating tobacco-related kidney injury.

Induction of oxidative stress in kidney

Oxidative stress has a critical role in the pathophysiology of several kidney diseases, and many complications of these diseases are mediated by oxidative stress, oxidative stress-related mediators, and inflammation. Several systemic diseases such as hypertension, diabetes mellitus, and hypercholesterolemia; infection; antibiotics, chemotherapeutics, and radiocontrast agents; and environmental toxins, occupational chemicals, radiation, smoking, as well as alcohol consumption induce oxidative stress in kidney. We searched the literature using PubMed, MEDLINE, and Google scholar with “oxidative stress, reactive oxygen species, oxygen free radicals, kidney, renal injury, nephropathy, nephrotoxicity, and induction”. The literature search included only articles written in English language. Letters or case reports were excluded. Scientific relevance, for clinical studies target populations, and study design, for basic science studies full coverage of main topics, are eligibility criteria for articles used in this paper.

Chronic nicotine exposure exacerbates acute renal ischemic injury

Recent epidemiological reports showed that smoking has a negative impact on renal function and elevates the renal risk not only in the renal patient but perhaps also in the healthy population. Studies suggested that nicotine, a major tobacco alkaloid, links smoking to renal dysfunction. While several studies showed that smoking/chronic nicotine exposure exacerbates the progression of chronic renal diseases, its impact on acute kidney injury is virtually unknown. Here, we studied the effects of chronic nicotine exposure on acute renal ischemic injury. We found that chronic nicotine exposure increased the extent of renal injury induced by warm ischemia-reperfusion as evidenced by morphological changes, increase in plasma creatinine level, and kidney injury molecule-1 expression. We also found that chronic nicotine exposure elevated markers of oxidative stress such as nitrotyrosine as well as malondialdehyde. Interestingly, chronic nicotine exposure alone increased oxidative stress and injury in the kidney without morphological alterations. Chronic nicotine treatment not only increased reactive oxygen species (ROS) production and injury but also exacerbated oxidative stress-induced ROS generation through NADPH oxidase and mitochondria in cultured renal proximal tubule cells. The resultant oxidative stress provoked injury through JNK-mediated activation of the activator protein (AP)-1 transcription factor in vitro. This mechanism might exist in vivo as phosphorylation of JNK and its downstream target c-jun, a component of the AP-1 transcription factor, is elevated in the ischemic kidneys exposed to chronic nicotine. Our results imply that smoking may sensitize the kidney to ischemic insults and perhaps facilitates progression of acute kidney injury to chronic kidney injury.

Comparable renovascular protective effects of moxonidine and simvastatin in rats exposed to cigarette smoke

Renovascular impairment plays a major role in smoking-induced nephrotoxicity. This study investigated the effect of the imidazoline I(1)-receptor/alpha(2)-adrenoceptor agonist moxonidine, as compared to the lipid lowering drug simvastatin, on abnormalities induced by cigarette smoke (CS) in renovascular reactivity. Six rat groups were used: control, CS (twice a day for 6weeks), simvastatin, moxonidine, CS+simvastatin, and CS+moxonidine. CS exposure increased plasma urea and creatinine and reduced plasma and renal nitrate/nitrite (NOx). In isolated perfused phenylephrine-preconstricted kidneys of CS rats, vasodilator responses to carbachol or isoprenaline, but not papaverine, were attenuated. Nitric oxide synthase (NOS) inhibition by N(G)-nitro-L-arginine (L-NNA) reduced carbachol vasodilations in control but not CS kidneys, suggesting the impairment of NOS activity by CS. Simultaneous administration of moxonidine or simvastatin abolished CS-induced abnormalities in indices of renal function, NOx, and vasodilations caused by carbachol or isoprenaline. The possibility whether alterations in antioxidant or lipid profiles contributed to the interaction was investigated. CS increased renal malondialdyde and decreased glutathione, and glutathione peroxidase, superoxide dismutase and catalase activities. Further, CS reduced plasma HDL and increased cholesterol, triglycerides, and LDL. Simvastatin or moxonidine abolished the deleterious CS effects on antioxidant activity; the lipid profile was normalized by simvastatin only. These findings highlight that renovascular dysfunction caused by CS and the underlying oxidative damage is evenly attenuated by moxonidine and simvastatin.

Ameliorative effect of caffeic acid phenethyl ester on histopathological and biochemical changes induced by cigarette smoke in rat kidney

It was aimed to investigate the histopathological and biochemical changes in kidney tissues of rats exposed to cigarette smoke and possible protective effects of caffeic acid phenethyl ester (CAPE) on these changes. Twenty one male Wistar albino rats were divided into three equal groups. Animals in group I were used as control. Rats in group II were exposed to cigarette smoke and rats in group III were exposed to cigarette smoke and daily administration of CAPE. At the end of the 60-day experimental period, all the animals were sacrificed by decapitation. The serum samples obtained from the animals were studied for uric acid, creatinine and blood urine nitrogen (BUN) levels. Following routine histological procedures, kidney tissue specimens were examined under a light microscope. In addition, dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities and malondialdehyde (MDA) and nitric oxide (NO) contents were determined spectrophotometrically in tissue samples. It was found that serum uric acid and BUN levels of the rats exposed to cigarette smoke alone were elevated, although serum creatinine levels did not significantly change. Furthermore, renal SOD, GSH-Px, NO and MDA levels were significantly increased. These increases in serum BUN, and renal SOD, GSH-Px, NO and MDA levels were significantly inhibited by CAPE treatment. In light microscopic observations of tissues from rats exposed to smoke, mesangial cell proliferation in the renal corpuscles, dilatation and congestion in the peritubular capillaries and degenerative alterations in the proximal tubules were noted. There were also atrophic renal corpuscles. However, these histopathological changes were partially disappeared in the rats exposed to cigarette smoke plus CAPE. The present findings indicate that cigarette smoke causes impairment in renal structure and function, which can be prevented by CAPE administration.

Effects of cigarette smoke and alcohol on ciliated tracheal epithelium and inflammatory cell recruitment

Ciliated epithelium represents the first line of host defense against lung infection. Most alcoholics smoke and are at high risk for developing lung infections. We reported that cigarette smoke activates protein kinase C (PKC) and alcohol desensitizes ciliary beat frequency (CBF) to beta-agonists in bovine bronchial epithelial cells in vitro. The combined effect of smoke and alcohol exposure on mouse ciliated tracheal epithelium has not been studied in vivo. We hypothesized that previously observed in vitro effects of smoke and alcohol exposure could be replicated in vivo. Female C57BL/6 mice were exposed to whole body cigarette smoke only, 20% alcohol ad libitum in drinking water only, or the combination of cigarette smoke plus alcohol for 6 wk. Bronchoalveolar lavage (BAL) cell populations, CBF, and airway kinase activity were assessed. Total BAL cells were decreased in animals exposed to alcohol alone and increased in animals exposed to smoke alone. Mice receiving smoke and alcohol had cell levels similar to smoke alone. Baseline CBF was not affected in any group; however, isoproterenol stimulation of CBF was blunted by alcohol exposure and actually slowed below baseline in the smoke plus alcohol group. Isoproterenol-induced PKA activity was inhibited in mice receiving alcohol independent of smoke exposure. Smoke activated PKC independent of alcohol. The isoproterenol-induced slowing below baseline of CBF after combined smoke and alcohol exposure demonstrates a novel ciliary impairment likely related to the combination of alcohol-mediated PKA desensitization and smoke-stimulated PKC activation, possibly through acetaldehyde present in the vapor phase of cigarette smoke.

The effects of chronic exposure to ethanol and cigarette smoke on the formation of peroxynitrite, level of nitric oxide, xanthine oxidase and myeloperoxidase activities in rat kidney

The aim of this study was to investigate the effects of chronic ethanol intake and cigarette smoke exposure on rat kidney. The animals were divided into four experimental groups: (1) the control group (C), (2) the ethanol group (E), (3) the cigarette smoke group (CS), and (4) the cigarette smoke plus ethanol group (CS+E). Rats in E, CS and CS+E groups were treated with ethanol and/or cigarette smoke for 6 months. The animals were killed and the kidneys were removed to determine the activity of xanthine oxidase (XO), myeloperoxidase (MPO) and the levels of nitric oxide (NO). Histopathological and immunohistochemical analysis were performed in kidney tissues. The activity of XO/g protein were 2.8 +/- 0.3, 5.2 +/- 0.3, 3.2 +/- 0.1, and 7.4 +/- 0.7 U for C, E, CS and CS+E groups, respectively. In groups E, and CS+E, the XO values were significantly higher than in group C (P < 0.05). The increase in XO activity of CS was not significantly different from group C (P > 0.05). There was a significant increase in XO activity of group CS+E as compared to CS and E groups (P < 0.05), and also a significant difference in XO activity between E and CS was observed (P < 0.05). The activity of MPO/g protein were 13.5 +/- 0.6, 16.2 +/- 1.1, 14.7 +/- 1.1, 23.8 +/- 0.9 U for C, E, CS, and CS+E groups, respectively. While MPO activity of kidneys from group CS+E were significantly higher as compared to C, CS, and E groups (P < 0.05), there was no significant difference among the groups of C, CS, E (P > 0.05). The levels of NO/g wet tissue were 347.7 +/- 8.5, 261.1 +/- 4.8, 329.8 +/- 5.6, and 254.2 +/- 3.8 nmol for C, E, CS, and CS+E groups, respectively. In groups of E and CS+E, the NO values were significantly lower than that of group C animals (P < 0.05). Although we detected lower NO levels in the E and CS+E groups than in CS group (P < 0.05), a significant difference in NO levels between CS+E and E groups was not observed. In the histopathological analysis of the kidney slices, severe degenerations in kidney tissues of group CS, E, CS+E were observed. Generally, the histological changes in kidney of CS+E and E groups were more severe than those observed in CS alone. While we observed a strong immunoreactivity for anti-nitrotyrosine antibody in kidneys of group CS+E, examination of sections from rat kidneys in group E revealed moderate staining. On the other hand, group CS had very little immunostaining. There was no immunostaining in group C. We concluded that chronic ethanol administration and cigarette smoke exposure may cause oxidative and nitrosative stress which lead to rat kidney damage.

Thiol/disulfide redox status is oxidized in plasma and small intestinal and colonic mucosa of rats with inadequate sulfur amino acid intake

Low molecular weight thiol/disulfide redox pools are dependent upon extracellular cysteine (Cys) availability. We determined whether dietary sulfur amino acid (SAA) deficiency induces oxidative stress in vivo, as determined by redox state of major thiol/disulfide couples in plasma [Cys/cystine (CySS)] and intestinal mucosa [glutathione (GSH)/glutathione disulfide (GSSG)]. Rats were fed isocaloric, isonitrogenous semipurified diets: either SAA-adequate (control), SAA-deficient, or SAA-supplemented, pair-fed to intake of the SAA-deficient group. Reference rats consumed standard rat food ad libitum. After 7 d, plasma and gut mucosal samples were analyzed for Cys, CySS, GSH and GSSG, and the redox potentials of Cys/CySS and GSH/GSSG were determined. Mean daily food intake in the pair-fed rats was similar (approximately one-half of reference-rat intake). Body weight decreased in all pair-fed groups, but rats fed the SAA-deficient diet lost significantly more body weight. Dietary SAA deficiency decreased GSH concentrations in both plasma and gut mucosa, increased plasma GSSG, and oxidized plasma and gut mucosal GSH/GSSG redox and plasma Cys/CySS redox. SAA supplementation resulted in a more reducing plasma Cys/CySS redox potential. Reference rats exhibited similar tissue and plasma GSH/GSSG redox as rats that ate semipurified SAA-adequate rat food, which provided similar net SAA intake. Our in vivo data show that inadequate dietary SAA intake oxidizes the thiol/disulfide redox status in rat-gut mucosa and plasma. Such oxidation of redox pools is associated with oxidative stress and the onset or progression of several pathological conditions. Thus, dietary SAA deficiency could contribute to the progression of disease by causing an oxidation of these components.

Ethanol-induced alterations of the antioxidant defense system in rat kidney

We report here the effects of chronic ethanol consumption on the antioxidant defense system in rat kidney. Thirty-two male Wistar rats were randomly divided in two identical groups and were treated as follows: control group (water for fluid) and the ethanol-fed group (2 g/kg body weight/24 h). The animals were sacrificed after 10 weeks, and respectively 30 weeks of ethanol consumption, and the renal tissue was isolated and analyzed. Results revealed that kidney alcohol dehydrogenase activities increased significantly after ethanol administration, but the electrophoretic pattern of alcohol dehydrogenase isoforms was unmodified. The SDS polyacrylamidegel electrophoretic study of kidney proteins has revealed the appearance of two new protein bands after long-term ethanol consumption. The kidney reduced glutathione/oxidized glutathione ratio decreased, indicating an oxidative stress response due to ethanol ingestion. The malondialdehyde contents and xanthine oxidase activities were unchanged. The antioxidant enzymatic defense system showed a different response during the two periods of ethanol administration. After 10 weeks, catalase, glutathione peroxidase, glutathione reductase, and glucose-6-phosphate dehydrogenase were activated, while superoxide dismutase, glutathione transferase, and gamma-glutamyltranspeptidase levels were stationary. After 30 weeks, superoxide dismutase and glutathione peroxidase activities were unmodified, but catalase, glutathione transferase, gamma-glutamyltranspeptidase, glutathione reductase, and glucose-6-phosphate dehydrogenase activities were significantly increased. Remarkable changes have been registered after 30 weeks of ethanol administration for glutathione reductase and glucose-6-phosphate dehydrogenase activities, including an increase by 106 and 216' of control values, respectively. These results showed specific changes in rat kidney antioxidant system and glutathione status as a consequence of long-term ethanol administration.

Arsenic and cigarette smoke synergistically increase DNA oxidation in the lung

Epidemiological evidence has indicated that arsenic and cigarette smoking exposure act synergistically to increase the incidence of lung cancer. Since oxidative damage of DNA has been linked to cancer, our hypothesis is that aerosolized arsenic and cigarette smoke work synergistically to increase oxidative stress and increase DNA oxidation in the lung. To test this hypothesis male Syrian golden hamsters were exposed to room air (control), aerosolized arsenic compounds (3.2 mg/m3 for 30 minutes), cigarette smoke (5 mg/m3 for 30 minutes), or both smoke and arsenic. Exposures were for 5 days/week for 5 or 28-days. Animals were sacrificed one day after the last exposure. In the 28-day group, glutathione levels and DNA oxidation (8-oxo-2'-deoxyguanosine (8-oxo-dG)) were determined. Our results show that in the 28-day arsenic/smoke group there was a significant decrease in both the reduced and total glutathione levels compared with arsenic or smoke alone. This correlated with a 5-fold increase in DNA oxidation as shown by HPLC. Immunohistochemical localization of 8-oxo-dG showed increase staining in nuclei of airway epithelium and subadjacent interstitial cells. These results show that dual exposure of arsenic and cigarette smoke at environmentally relevant levels can act synergistically to cause DNA damage.

Alcohol-induced oxidative stress and reduction in oxidation by ascorbate/L-cys/ L-met in the testis, ovary, kidney, and lung of rat

Chronic exposure to high doses of alcohol results in many pathophysiologic changes in cellular function caused by the alcohol itself and the effects of its metabolism (ie, generation of acetaldehyde, nicotinamide adenine dinucleotide [NADH], free radicals, and oxidative stress). However, the role of each of these effects on the testis, ovary, kidney, and lung in chronic alcoholism must be investigated. It is hypothesized that cysteine-methionine and vitamin C might neutralize harmful compounds and potentiate the antioxidant capacity of the cell or tissue. In this study, rats were fed regular diets and were maintained in the following groups for 90 days: control group; alcoholic group (2.5 g of 50% ethanol/kg body wt administered intragastrically every other day); and alcoholic with antioxidant supplement group (2.5 g of 50% ethanol plus a solution containing 200 mg vitamin C, 100 mg cysteine, and 100 mg methionine/kg body wt administered intragastrically every other day). After treatment had been completed, rat blood, testis, ovary, kidney, and lung were taken for biochemical analysis. Mean alcohol level in the alcoholic group was raised (by 40%) compared with that in the control group, but it was lower (by 30%) in the antioxidant-supplemented group than in the alcoholic group. In accordance with the levels of alcohol, oxidized protein and lipid content in the testis, ovary, kidney, and lung were low in the control group, higher in the antioxidant-supplemented group, and highest in the alcoholic group. It is interesting to note that levels of glutathione in the testis and lung of the alcoholic group were lower than those in both the control and antioxidant-supplemented groups. In conclusion, chronic alcohol administration led to a significant increase in the level of protein oxidation in the ovary and kidney of rats. Simultaneous intake of ascorbate/L-cys/L-met, along with ethanol, partly attenuated the amount of lipid and protein oxidation that occurred in tissues with oxidative stress caused by alcohol consumption.

Sodium pertechnetate (Na99mTcO4) biodistribution in mice exposed to cigarette smoke

BACKGROUND: The biological effects of cigarette smoke are not fully known. To improve our understanding of the action of various chemical agents, we investigated the biodistribution of sodium pertechnetate (Na99mTcO4) in mice exposed to cigarette smoke. METHODS: Fifteen BALB/c male mice were exposed to the smoke of nine whole commercial cigarettes per day, 3 times/day, for up to 10 days to whole body exposure in a chamber. A control group of 5 BALB/c male mice was sham-smoked. One day later, the exposed and control groups of mice received (7.4 MBq/0.3 ml) of Na99mTcO4 before being killed at 30 min. Bones, brain, heart, intestine, kidney, liver, lungs, muscle, pancreas, spleen, stomach, testis and thyroid were weighed and these organs and blood radioactivity recorded with a gamma counter. The percentage per gram of tissue of injected dose (%ID/g) was determined for each organ. RESULTS: Cigarette smoke significantly decreased (p < 0.05) the %ID/g in red blood cells, bone, kidney, lung, spleen, stomach, testis and thyroid of the exposed mice. CONCLUSION: The toxic effects of cigarette smoke reduced the Na99mTcO4 biodistribution.