Proteomic analysis of silver nanoparticle toxicity in rat

Silver nanoparticles (SNPs) have received considerable attention recently, because SNPs with different shapes and sizes exhibit variable antimicrobial activity, which makes them useful for medical and hygienic purposes. SNPs have been detected in various tissues and organisms after inhalation, oral ingestion, and contact with the skin, indicating that SNPs can be distributed to different body tissues after uptake. Thus, the toxicity of SNPs to different body tissues after their uptake needs to be studied. In this study, we performed a proteomic analysis of liver, lung, and kidney tissues in rats exposed to approximately 50 nm SNPs by intravascular injection. Then, the differentially expressed proteins representing a dose-dependent response were identified. The differentially expressed proteins were mostly related to the known toxicity of SNPs, such as apoptosis, increased reactive oxygen species, thrombus formation, and inflammation. Additionally, proteins related to metabolic disorders including diabetes were identified as differentially expressed proteins in kidney, based solely on the analysis of the protein profile and related disease pathway. In conclusion, the differentially expressed proteins identified in this study could provide basic data for understanding the toxic and pathological responses of SNP-exposed tissues and to identify candidate SNP toxicity biomarkers.     

Effects of cigarette smoke generated by different smoking machines on pulmonary macrophages of mice and rats

C57BL/6 male mice and Sprague Dawley male rats were exposed to cigarette smoke generated by different smoking machines. Animals inhaled 20% smoke from the Kentucky 2A1 Reference cigarette twice daily 7 days per week for 1 to 5 weeks. Microscopic assessment of lung tissue revealed no abnormal manifestations in animals exposed to smoke in the different smoking machines. However, pulmonary macrophages from lungs of animals exposed to smoke in one of the machines contained crystalline material resembling aluminum silicate. It was determined that this material originated from a structural component of the machine and not from cigarette smoke. It was also observed that smoke generated in the different smoking machines did not elevate equally the intraspecie and interspecie population size of the pulmonary macrophages. The present study points out the need in research dealing with tobacco smoke inhalation for careful evaluation and monitoring of the smoke generation and delivery systems, as well as for awareness of inherent differences in biological responses to smoke among species.     

Alteration of Pulmonary Surfactant Proteins in Rats Chronically Exposed to Cigarette Smoke

Surfactant proteins (SP) play an important role in enhancing the surface properties of pulmonary surfactant and participate in host–defense mechanism(s) of the lung. Although it is known that cigarette smoking alters both pulmonary surfactant lipid composition and function, its effect on SPs is unknown. The present study was carried out to determine if chronic exposure to cigarette smoke alters pulmonary SPs, namely, SP-A and SP-B, in a rat model. Sprague–Dawley rats were exposed to cigarette smoke in a nose-only exposure system twice a day, every day for 70 weeks. At termination, bronchoalveolar lavage (BAL) fluid and the lung tissues were collected from room control, sham-treated (SH), and smoke-exposed (SM) animals for analyses. The total protein levels in the BAL fluid of SM rats tended to be higher but were not statistically different from those of the SH group. However, the albumin content of BAL fluid in SM rats, measured by quantitative immunoblotting, was significantly higher than in control groups. Compared to control groups, SP-A and SP-B levels in the BAL fluid of SM rats were significantly reduced by 25 and 50%, respectively, when expressed as units per microgram of BAL fluid protein. However, when calculated as total BAL fluid SP recovered per rat, only the SP-B levels of SM rats were significantly different from the control groups. Further analysis by ELISA confirmed the reduced levels of SP-B in SM rats. In contrast to BAL fluid, the lung tissue levels of SP and their respective mRNAs were not significantly different between the control and smoke-exposed groups. These results show a selective reduction in SP-B content on the bronchoalveolar surface following chronic exposure to cigarette smoke and suggest an inhibitory effect of cigarette smoke on surfactant secretory processes and/or a localized destruction of SPs on the bronchoalveolar surface.     

Up-regulation of RAGE and S100A6 in rats exposed to cigarette smoke

Cigarette smoke has been widely investigated in terms of epidemiology and pathological endpoints in relation to human lung diseases and animal study. In this study we exposed Wistar rats to cigarette smoke at concentrations of 20% and 60% to explore potential molecular mechanisms at the protein level. Exposures were conducted twice a day, 5 days a week for 43 weeks. As a major metabolite of nicotine in cigarette, cotinine level in rat urine was determined by HPLC–MS. A dose-dependent analysis indicated that cotinine may be used as an exposure marker of cigarette smoke. Expression of receptor for advanced glycation endproducts (RAGE), an immunoglobulin super family that triggers the intracellular signal cascade reaction leading to inflammation and its ligand S100A6 (calgranulin) in bronchial epithelial cells and lung tissues of rats, were found to be positive correlated with cotinine levels, indicating that RAGE and S100A6 may be attributable to inflammation and oxidative damage caused by cigarette smoke.     

Cigarette smoke exposure does not prevent cadmium-induced alterations in rat lungs.

Cigarette smoke has been demonstrated to suppress the biosynthesis of connective tissue in the lung. To further characterize this suppressant effect, we studied the ability of cigarette smoke to prevent or ameliorate cadmium-induced alterations in rat lungs in vivo. The effects of beta-aminopropionitrile (beta APN), an agent that inhibits the cross-linking of elastin, also were studied. Eighty-eight young female Long-Evans rats were randomly divided into seven groups as follows: control, cigarette smoke, sham smoke, beta APN, cadmium, cadmium + cigarette smoke, and cadmium + beta APN. Each animal in the cigarette smoke group was exposed to mainstream smoke generated from University of Kentucky 2R1 reference cigarettes (10 puffs daily for 12 wk). Sham-treated animals received room air in place of cigarette smoke. beta APN (0.5 g/kg) was injected intraperitoneally twice weekly. In cadmium-treated groups, each rat received intermittently three intratracheal instillations of cadmium chloride (0.15 mumol/kg) over a 5-d period. For the cadmium + cigarette smoke group, smoke exposure began 3 d after the first cadmium instillation and was continued for 12 wk. The beta APN administration began 5 d before cadmium instillation and also was continued for 12 wk. After these treatments, pulmonary function and lung morphometry were examined. Neither cigarette smoke, sham smoke, nor beta APN produced significant changes in lung function or morphometry. Cadmium caused significant decreases in total lung capacity, dynamic and static compliance, and carbon monoxide diffusing capacity, as well as significant increases in lung weight and alveolar wall thickness. In addition, the quasistatic deflation pressure-volume curve showed a rightward shift whereas the mean linear intercept of the alveoli did not change significantly. Efforts to prevent or ameliorate the changes through exposure to cigarette smoke or administration of beta APN were unsuccessful. It is concluded that interventions designed to inhibit the biosynthesis of lung connective tissue do not perforce inhibit the development of cadmium-induced pulmonary changes in the rat.     

Lack Of Effect On Rat Lung Stress-Inducible Heat Shock Protein 70 After Acute Tobacco Smoke Inhalation

Abstract

few investigations have examined in vivo expression of heat shock proteins (HSPs) and stress proteins in the lung following environmental stress. Such proteins are thought to provide cellular protection against environmental trauma. This study describes the initial effects of tobacco smoke inhalation on stress-inducible HSP 70 level in the rat lung. Specifically, the expression and possible elevation of stress-inducible HSP 70 in the rat lung was examined 5 h following inhalation of tobacco smoke from one research cigarette (2R1/University of Kentucky). Male Sprague-Dawley rats were exposed nose-only to tobacco smoke (n = 6), while control rats were exposed to purified filtered air (n = 6). Samples of the peripheral lung from the right apical lobe were homogenized and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE), protein immunoblotting, chemiluminescence detection, and computerized optical densitometric scanning. The results revealed that stressinducible HSP 70 is present constitutively in the control rat lung at 30.83 ± 14.81 (SD) optical units and is elevated slightly at 35.33 ± 12.05 (SD) optical units but not significantly (p = .77) in lungs that inhaled tobacco smoke. A more complete time-course profile will determine whether stressinducible HSP 70 levels are elevated significantly following tobacco smoke inhalation. Changes in the levels of stress proteins that are elevated in damaged lung cells may be of utility for toxi-cological assessment following inhalation exposures to either tobacco smoke or other types of pulmonary toxicants in the atmosphere.     

Exposure to cigarette smoke downregulates β2-adrenergic receptor expression and upregulates inflammation in alveolar macrophages

Abstract

Cigarette smoke-triggered inflammation is important in the pathophysiology of chronic obstructive pulmonary disease (COPD). β₂-Adrenergic receptor (β₂-AR) is abundantly expressed on inflammatory cells, which is associated with inflammation regulation. To observe alterations in inflammation, pathological changes in lung tissues, and detect changes in β₂-AR expression, rats were exposed for 4 months to cigarette smoke. Pathological changes were observed in lung tissue sections. The levels of inflammatory mediators tumor necrosis factor (TNF)-α, interleukin (IL)-1β in bronchoalveolar lavage fluid (BALF), and lung tissues were measured using enzyme-linked immunosorbent assay (ELISA). Nuclear factor (NF)-κB activity was detected by electrophoretic mobility shift assay (EMSA). Exposure to this regimen of cigarette smoke induced peribronchial and perivascular lymphocytic aggregates and parenchymal accumulation of macrophages in rats. EMSA demonstrated that smoke exposure enhanced NF-κB activation in rats’ alveolar macrophages (AMs). Compared with the control group, smoke exposure induced a notable increase in TNF-α and IL-1β in BALF, lung tissues, and a decrease of β₂-AR expression of AMs. The expression of β₂-AR from AMs was inversely correlated with TNF-α and IL-1β levels of BALF. These data demonstrated that chronic smoke-triggered lung inflammation was accompanied by down-regulation of β₂-AR in rat lungs’ AMs.     

Effect of Cigarette Smoke Exposure on Biomarkers of Lung Injury in the Rat

Abstract

Rats exposed to tobacco cigarette smoke (CS) via inhalation from a high-tar cigarette for 4 h/day over a 14-day period showed measurable changes in specific biochemical and immunological markers of lung injury when compared to control rats exposed to clean dry air. We found epithelial cell layer thickening and increased lung permeability as measured by histopathological examination, and increased levels in hexose and protein exudation present in bronchoalveolar lavage fluid. Exposure to CS also caused a significant reduction in immunoglobulin A (lgA) levels (p < .001), which persisted after postexposure recovery. In addition, alveolar macrophages from rats exposed to CS were unresponsive to lipopolysaccharide stimulation in vitro as shown by reduced expression of cytokine interleukin 1β mRNA compared to air controls. These results suggest that high-tar cigarette smoke can induce disfunctional changes in immune systems. However, as no reproducible smoke-induced changes were seen using medium-tar cigarettes, we have to conclude that the rat may not be the most sensitive species in which to evaluate the mode of action of cigarette smoke on the lung.     

GLUTATHIONE LEVELS PLAY A ROLE IN CIGARETTE SMOKE-INDUCED CELL PROLIFERATION IN THE RAT LUNG

To investigate the role of glutathione (GSH), an important cellular oxidant defense mediator, in cellular proliferation induced by cigarette smoke exposure, we utilized two experimental protocols. The first protocol was designed with four groups of rats. Two groups were pretreated with diethyl maleate (DEM) to reduce tissue GSH levels. One nontreated and one DEM-treated group received cigarette smoke exposure; the other two groups received sham smoke exposure only. For the second protocol we used a lung explant system, and in addition to smoke- and sham smoke-exposed groups, we supplemented cellular GSH levels with GSH added to the medium. Cell proliferation was assessed by cell labeling with 5-bromo-2'-deoxyuridine (BrdU). We found that, in the intact rat, cigarette smoke induced cell proliferation in the airway epithelium and walls and in the vessel walls; GSH depletion induced or increased this proliferative effect in airway walls and in the vascular endothelium and walls. In the lung explants, cigarette smoke also induced cell proliferation in airway epithelium and airway and vessel walls, and GSH supplementation reduced proliferation in both control and smoke exposed airway epithelium. In the intact animals, smoke had no effect on tissue GSH either immediately or after 24 h. However, exposure of the explants to cigarette smoke exposure increased GSH after 24 h. We conclude that (1) cigarette smoke-induced cellular proliferation is a direct effect of cigarette smoke that probably does not require the presence of smoke-evoked inflammatory cells, and (2) smoke-induced cell proliferation is related, at least partially, to the level of GSH and, by implication, to the balance between oxidants and antioxidants in the tissues.     

Effect of Cigarette Smoke on UDP-Glucuronosyltransferase Activity and Cytochrome P450 Content in Liver,Lung and Kidney Microsomes in Mice

Abstract: The effect of cigarette smoke on the expression of several cytochromes P450 (CYP) and UDP-glucuronosyltransferases (UGT) was studied in mice. The animals were exposed to cigarette smoke for 4 to 30 days. Enzymatic activities supported by CYP1A1, 1A2, 2B, 2E1 and the glucuronidation activity toward phenols were measured in lung, liver and kidney microsomes. Cigarette smoke induced several CYPs, especially in lung. CYP2E1 was more induced than CYP1A1 in this organ. The expression of CYP2E1 was also increased in kidney (5.6 times after 30 days). The glucuronidation in kidney was non-sensitive to the treatment whatever substrate used. In contrast, this activity was enhanced in liver and particularly in lung, in which the glucuronidation of 1-naphthol and 2-hydroxybiphenyl was increased by 122 and 180%, respectively. Interestingly, the times of induction differed according to the substrate used, thus suggesting the presence of different UGTs active toward phenols that were differentially affected by cigarette smoke. The LIGT activities toward phenols were low in lung, when compared with those measured in liver or kidney. In conclusion, cigarette smoke greatly affected both glucuronidation activity and the hydroxylation reactions supported by CYPs in mouse liver and lung.     

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.     

Proteomic Analysis of Colonic Mucosal Tissue from Tuberculous and Ulcerative Colitis Patients

Changes in the expression profiles of specific proteins leads to serious human diseases, including colitis. The proteomic changes related to colitis and the differential expression between tuberculous (TC) and ulcerative colitis (UC) in colon tissue from colitis patients has not been defined. We therefore performed a proteomic analysis of human TC and UC mucosal tissue. Total protein was obtained from the colon mucosal tissue of normal, TC, and UC patients, and resolved by 2-dimensional electrophoresis (2-DE). The results were analyzed with PDQuest using silver staining. We used matrix-assisted laser desorption ionization time-of-flight/time-of-flight spectrometry (MALDI TOF/TOF) to identify proteins differentially expressed in TC and UC. Of the over 1,000 proteins isolated, three in TC tissue and two in UC tissue displayed altered expression when compared to normal tissue. Moreover, two proteins were differentially expressed in a comparative analysis between TC and UC. These were identified as mutant β-actin, α-enolase and Charcot-Leyden crystal protein. In particular, the expression of α-enolase was significantly greater in TC compared with normal tissue, but decreased in comparison to UC, implying that α-enolase may represent a biomarker for differential diagnosis of TC and UC. This study therefore provides a valuable resource for the molecular and diagnostic analysis of human colitis.     

Cigarette smoking, metabolic activation and carcinogenesis

Epidemiologically, it has been suggested that cigarette smoking is closely associated with an increased risk of cancers in various organs such as the lung, oropharynx, stomach, pancreas, liver and colon. Nevertheless, influences of cigarette smoking on experimental tumorigenesis in organs other than the respiratory tract remain to be elucidated. In our experimental studies, it has been shown that cigarette smoke exposure induces hepatic CYP enzymes, especially CYP1A2, in both rats and hamsters, and S9 fraction from their livers exposed to cigarette smoke specifically increases the mutagenicity in Ames assay of various heterocyclic amines (HCAs) contained in cigarette smoke and cooked food, which is in good agreement with the fact that HCAs are principally activated by CYP1A2 to proximate carcinogens. In fact, cigarette smoke exposure enhanced liver carcinogenesis in rats induced by 2-amino-3, 8-dimethylimidazo[4, 5-f]quinoxaline (MeIQx), a major HCA. Furthermore, in our recent study, it was also shown that cigarette smoke exposure induces hepatic CYP2A8 in hamsters, which is homologous to CYP2A6 in human, and hepatic S9 fraction exposed to cigarette smoke increases the mutagenicity of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco specific nitrosamine, which is in line with the fact that NNK is metabolically activated by CYP2A6. Keeping these data, the aim of this review is to discuss any relevancy of modulated metabolic activation by cigarette smoking to cancer risk in human.     

The effect of resveratrol in tracheal tissue of rats exposed to cigarette smoke

Objective: The aim of this study was to evaluate the effect of resveratrol on the tracheal tissue of rats exposed to cigarette smoke.

Materials and methods: 40 adult Wistar albino rats were divided into four groups for an experiment of 6 weeks. Animals in group 1 were controls (n?=?10). Rats in group 2 were exposed to cigarette smoke only, and rats in group 3 received daily intraperitoneal injections of resveratrol (10?mg/kg/d). Animals in group 4 were exposed to both cigarette smoke and intraperitoneal injections of resveratrol. Rats of all groups were sacrificed using cervical dislocation. The tracheas were removed and embedded in paraffin blocks. Sections of 4–5 μm thickness were prepared from the blocks. These sections were stained with hematoxylin and eosin, periodic acid–Schiff, and Alcian blue and viewed with a Leica DFC 280 light microscope.

Results: Tracheal sections showed that, in group 2 (cigarette smoke group), there was desquamation of epithelial cells into the tracheal lumen, loss of cilia in the epithelial layer, an increase of goblet cells, activation of serous glands at the submucosa, and cell infiltration. In group 4 (cigarette smoke + resveratrol group), all these findings also existed but only a few sections were affected. It was observed that cigarette smoking caused morphological changes such as epithelial degeneration in the upper airway. These morphological changes were correlated with the amount of toxic substances in the cigarette smoke.

Conclusion: We found that resveratrol had a preventive role in the histopathological changes caused by cigarette smoking in the rat trachea.     

Comparison of the inhalation toxicity of kretek (clove cigarette) smoke with that of American cigarette smoke. II. Fourteen days,exposure

The comparative repeat dose toxicity of American cigarettes and kreteks (Indonesian cigarettes containing approximately 60% tobacco and 40% shredded clove buds) was assessed by exposure of groups of five male and five female rats to equivalent (approximately 2 mg/l in terms of total particulate matter) concentrations of smoke from each type of cigarette over 15 consecutive days. The smoke was delivered nose only using an HRC Rodent Smoking Machine (Mark IV). For each type of cigarette, three doses were used. These were achieved by regulating the daily total duration of exposure to smoke. The different doses used were 2x, 4x and 6x, 15-min exposures, presented daily over a period of approximately 6 h. Intergroup comparisons were made between American and kretek groups which received the same daily durations of smoke exposure. Higher doses of smoke resulted in reduced bodyweight gains and food consumption in male groups; the response of female groups was not as clear. At the highest dose, male rats exposed to kretek smoke gained significantly more weight by comparison with males exposed to American smoke. Higher doses of smoke tended to increase water consumption in both sexes of groups exposed to American smoke; kretek smoke produced no obvious effect. Smoke exposures produced the expected responses in certain haematological and blood biochemical parameters attributed to exposure to CO and the irritants present in cigarette smoke. Such responses were, however, confined largely to the groups exposed to American smoke. Macroscopic pathological findings attributed to smoke inhalation were confined to the lungs, and consisted of minimal to moderate discolouration and incomplete collapse of the lung. The latter finding occurred in 60% of males and 60% of females in the American high dose group and 20% of females in the kretek intermediate dose group. The weights of several organs appeared to have been affected by smoke exposures. Of these, only the increase in lung weight associated with exposure to American smoke was considered remarkable. In females exposed to American smoke, the group mean lung weights were significantly higher than the corresponding kretek group lung weights. In males, the difference was significant at the intermediate dose level only. The histopathological lesions seen in the lungs were typical of the lesions encountered in inhalation studies with tobacco smoke and included increased numbers, vacuolation and brown pigmentation of macrophages, acute alveolitis, bronchiolar epithelial hyperplasia and cuboidal ciliated cell metaplasia of alveolar duct; the two latter findings were present in some American high dose rats only. Occasional foci of alveolar haemorrhage were seen in odd rats but the incidence was not clearly dose related for either type of cigarette; the highest incidence, 30%, was seen in the high dose American group. At all dose levels, the lesions encountered were more severe with American smoke. No unique lesions were detected with kretek smoke.     

Biological responses in rats exposed to cigarette smoke and Middle East sand (dust)

Respiratory symptoms are frequently reported in personnel deployed to the Middle East. This project characterized the respiratory toxicity of inhaled Iraqi sand (IS). Adult rats underwent a 6-wk inhalation to air or mainstream cigarette smoke (MSCS) (3?h/d, 5?d/wk) that included exposure to IS or crystalline silica (1?mg/m(3), 19?h/d, 7?d/wk) or air during the last 2 weeks. Assessments included motor activity, whole-body plethysmography, cytological and biochemical analysis of bronchoalveolar lavage fluid, lung metal burden, nasal and lung pathology, and changes in lung protein and gene expression. A number of metals including nickel, manganese, vanadium, and chromium were detected in IS. Elevated lung parenchyma aluminum, silica, barium, manganese, and vanadium concentrations were seen in IS-exposed rats, suggesting that several metals present in IS are bioavailable. Rats exposed to IS only developed mild inflammation in the anterior nose and lung. Silica inhalation was associated with some pulmonary responses that were not seen in IS-exposed rats, such as mild laryngeal and tracheal inflammation, mild tracheal epithelial hyperplasia, and elevated lung silica concentrations. MSCS inhalation with or without co-exposure to either IS or silica resulted in changes consistent with pulmonary inflammation and stress response. Rats exposed to MSCS and silica had more widespread airway lesions when compared with rats exposed to MSCS only. Silica-exposed rats had more robust pulmonary gene expression and proteomic responses than that seen in IS-exposed rat. Our studies show that the respiratory toxicity of IS is qualitatively similar to or less than that seen following short-term silica exposure.     

Serotonin receptors 5-HTR2A and 5-HTR2B are involved in cigarette smoke-induced airway inflammation,mucus hypersecretion and airway remodeling in mice

BackgroundCigarette smoke plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Recently, elevated serotonin (5-HT) levels were found in the plasma of COPD patients. The role of 5-HT and its receptors in airway inflammation and remodeling induced by cigarette smoke is unclear.MethodsBALB/c mice received the 5-HTR2A inhibitor ketanserin, the 5-HTR2B inhibitor RS-127445 or the natural 5-HTR2A/2B inhibitor quercetin intraperitoneally, then were exposed to cigarette smoke for 6 or 12 weeks. Control mice received placebo and were exposed to room air or cigarette smoke. Mice were sacrificed and bronchial alveolar lavage fluid (BALF) and lung tissue samples were collected.ResultsImmunohistochemistry and western blot confirmed an increase in both 5-HTR2A and 5-HTR2B expression in mouse lungs after exposure to cigarette smoke for 6 and 12 weeks. Cigarette smoke induced accumulation of macrophages and neutrophils and increased levels of inflammatory cytokines, including IL-1β and TNF-ɑ, in BALF and lung tissue; these effects were inhibited by ketanserin, RS-127445 and quercetin. Pretreatment with 5-HT receptor antagonists suppressed the goblet cell hyperplasia induced by 6- or 12-week exposure to cigarette smoke, based on Alcian blue-periodic acid Schiff staining. After 12 weeks of cigarette smoke exposure, Masson's staining showed fibrosis surrounding the mouse airways, and inhibitor pretreatment significantly attenuated the thickening and collagen deposition around the small airways.ConclusionsOur results suggest that cigarette smoke-induced airway inflammation and small airway remodeling are partially mediated by 5-HTR2A and 5-HTR2B, which could be a new therapeutic target for airway remodeling in COPD.     

Cigarette smoke and its extract delays ulcer healing and reduces nitric oxide synthase activity and angiogenesis in rat stomach

1. The purpose of the present study was to examine whether cigarette smoke and its extract could affect ulcer healing, angiogenesis and nitric oxide synthase (NOS) activity in the gastric mucosa. 2. Ulcerated rats were either exposed to cigarette smoke or given smoke extract once daily for 3 days. Rats were killed and stomachs were removed for the measurement of ulcer size, angiogenesis and NOS activity. 3. Angiogenesis and constitutive NOS activity were concomitantly and dose-dependently reduced by cigarette smoke or its extract. The same treatments also delayed ulcer healing. 4. These results indicate that cigarette smoke and its extract repress the processes of new blood vessel formation and NOS activity during tissue repair in the gastric mucosa. These could, in turn, retard the healing process in the gastric mucosa.     

Responses of rodent hepatic,renal and pulmonary aryl hydrocarbon hydroxylase following exposure to cigarette smoke

Using the British-American Tobacco Co. (B.-A.T.)-Mason inhalation system which releases a precisely-calibrated dilution of tobacco smoke into a chamber, male and female rats, guinea pigs, hamsters and gerbils were exposed to the optimum smoke concentration found to induce rat renal aryl hydrocarbon hydroxylase (AHH) (40 puffs of a 1 : 5 dilution of smoke from cigarettes prepared from a blend of Canadian flue-cured tobaccos). The tissue activity was measured in 9000 g supernatants of homogenates of lung, liver and kidney 6 h following exposure.Cigarette smoke was found to be a potent inducer of AHH, dilutions as high as 1 : 40 inducing this enzyme in rat kidney. Marked tissue, sex and species differences in basal AHH were observed. Induction up to 6-fold, was observed only in lung and kidney of male and female rats. In hamsters and gerbils, lung AHH was induced in both sexes but only renal AHH in female hamsters. In male and female guinea pigs, only the renal AHH was induced some 5-fold. Hepatic AHH was not inducible in any of the species studied. The analysis of changes in AHH activity in a responsive species and tissue(s) could be a valuable technique for the quantitative evaluation of biological effects of low concentrations of cigarette smoke.