Bronchoconstriction and delayed rapid shallow breathing induced by cigarette smoke inhalation in anesthetized rats

Bronchomotor and ventilatory responses to inhalation of cigarette smoke (50% concentration, 6 ml) were studied in anesthetized and vagotomized Sprague-Dawley rats. Low-nicotine cigarette smoke did not cause any detectable delayed response, whereas high-nicotine cigarette smoke induced rapid, shallow breathing, and a marked increase in airway resistance (R_L). The increase in f reached a peak (Δf=43±8%) at the 5th breath after the onset of smoke inhalation, preceding both the decrease in V_T (ΔV_T=−27±4%) and the increase in R_L (ΔR_L=89±19%); the latter 2 reached their peaks at approximately the 10th breath, displaying a similar temporal pattern of responses between them. The bronchomotor response to high-nicotine cigarette smoke was slightly attenuated but not prevented by prior administration of isoproterenol (0.2 mg/kg, intravenously [iv]), nor was the smoke-induced rapid, shallow breathing. In contrast, prior administration of mecamylamine (0.9 mg/kg, iv) completely abolished both the bronchomotor and ventilatory responses to smoke inhalation, indicating that nicotine is the primary causative agent responsible for these changes.     

Bronchoconstriction and apnea induced by cigarette smoke: Nicotine dose dependence

Recently, evidence was presented to suggest that nicotine absorbed from cigarette smoke was the main cause of smoke-induced bronchoconstriction (Hartiala et al., J Appl Physiol (1985) 59(1): 64–71). However, due to the qualitative nature of the data, it remains unclear whether cigarette-smoke-induced bronchoconstriction is related to the nicotine content of the smoke in a dose-dependent manner. Experiments were performed on intact anesthetized dogs (n = 6). Each animal spontaneously inhaled 300 cc smoke containing low (0.37 mg), medium (1.46 mg), or high (1.80 mg) levels of nicotine. Isometric tension was measured in an isolated tracheal segment not exposed to the smoke as an index of bronchoconstriction. In all dogs there was a nicotine dose-dependent increase in tracheal tension. The time in expiration (T_e) in the breath following smoke inhalation was prolonged, the magnitude of prolongation being dependent upon the nicotine content of the smoke. These results suggest that bronchoconstriction and changes in T_e induced by cigarette smoke are nicotine-dependent.     

Chronic pancreatic inflammation induced by environmental tobacco smoke inhalation in rats

OBJECTIVE: Despite a strong epidemiological association between cigarette smoking and pancreatic diseases, such as pancreatic cancer and chronic pancreatitis, the effects of long-term cigarette smoke inhalation on the pancreas have not been clearly determined. In the present study, we investigated the effect of cigarette smoke inhalation on the pancreas. METHODS: Thirty-six female Sprague Dawley rats were exposed to two different doses of environmental tobacco smoke averaging 100 mg or 160 mg/m3 total suspended particulate matter (TSP) per m3 for 70 min twice a day for 12 wk. The animals were sacrificed and examined for the effects of tobacco smoke exposure on pancreatic morphology and function. RESULTS: In 58% (7/12) of the animals, exposure to 160 mg/m3 TSP cigarette smoke induced a chronic pancreatic inflammatory process with fibrosis and scarring of pancreatic acinar structures. Animals with fibrotic alterations showed an induction of pancreatic pro-collagen 1 gene expression, and the infiltration of immune cells was accompanied by the expression of the inflammatory mediators MIP-1alpha, IL-1beta, and TGF-beta in 33% (4/12) of the animals. Acinar cell stress was manifested by a significant up-regulation of pancreatitis-associated protein expression (PAP) in smoke-exposed animals (smoke-exposed 6,932 +/- 1,236 vs control 3,608 +/- 305, p < 0.05). Possibly contributing to the morphological damage to the exocrine pancreas, the inhalation of cigarette smoke induced trypsinogen and chymotrypsinogen gene expression and, furthermore, reduced pancreatic enzyme content. CONCLUSIONS: This study provides experimental evidence of morphological pancreatic damage induced by the inhalation of cigarette smoke, which is likely to be mediated by alterations of acinar cell function.     

香烟烟雾提取物致大鼠膈肌细胞氧化损伤

目的研究经香烟烟雾提取物（CSE）刺激后大鼠膈肌细胞8一羟基脱氧鸟苷（8-OHdG）含量的变化以及细胞内活性氧（ROS）水平和8-羟基鸟嘌呤DNA糖苷酶1（OGGl）表达对8．OHdG含量变化的影响。方法用不同浓度CSE分别刺激大鼠膈肌细胞24、48和72h后,采用高效液相色谱．电化学法（HPLC—ECD）检测大鼠膈肌细胞8．OHdG的含量,流式细胞术检测大鼠膈肌细胞ROS水平,采用实时定量PCR检~IJOGG!mRNA水平,用Western印迹法检测OGGl蛋白水平。结果经相同CSE浓度分别刺激大鼠膈肌细胞24、48和72h后,大鼠膈肌细胞中8-OHdG含量、ROS水平及OGGlmRNA和蛋白水平均无明显差异。但经不同浓度CSE刺激相同时间后,10．00％CSE和20．00％CSE刺激组大鼠膈肌细胞8-OHdG含量明显高于对照组和5．00％CSE刺激组（P〈0．05）;大鼠膈肌细胞内ROS水平、OGGlmRNA和蛋白水平较对照组均明显升高（P〈0．05）;大鼠膈肌细胞8-OHdG含量与其ROS水平呈明显正相关（r=0．826,P：0．000）;经CSE刺激后,大鼠膈肌细胞OGGlmRNA和蛋白水平均高于对照组（P〈O．05）,但大鼠膈肌细胞8．OHdG含量与其OGGlmRNA和蛋白水平无明显相关（r=0．373,P=0．254;r=0．329,P=0．296）。结论CSE刺激可引起大鼠膈肌细胞8-OHdG升高,8-OHdG含量与ROS水平有关,但与其修复酶OGGl表达水平无明显相关。     

N-acetylcysteine prevents cigarette smoke induced small airways alterations in rats.

This study investigated the effect of cigarette smoke exposure and the potential protection N-acetylcysteine (NAC) in rat lungs. Forty-eight rats were exposed to cigarette smoke (CS) for 10 weeks, without (CS group) or with (CS+NAC group) oral intake of NAC 200 mg x rat(-1) x day(-1), or to fresh air (Control). All rat lungs were assessed in terms of lung function, ventilation distribution (nitrogen, helium and sulphur hexafluoride phase III slopes), and morphometry (airway wall thickening of small, medium and large bronchi). The small bronchi, defined as the airways with an internal perimeter <1,000 microm showed significantly thicker airway walls in the CS than in the Control group. By contrast, no airway wall thickening was observed in the CS+NAC group with respect to Control. Except for decreased lung volumes and compliance in CS and CS+NAC groups, which were entirely attributable to smaller body weight gain, lung function was indistinguishable from Control. Phase III slopes were significantly increased only in the CS group. In conclusion, smoke-induced alterations in the rat lungs were reflected in wall thickening of the small bronchi and increased ventilation maldistribution. These smoke-induced morphometric and ventilation distribution alterations were prevented by N-acetylcysteine.     

香烟烟雾致COPD模型大鼠气道纤毛结构变化的评价

目的 应用气道纤毛超微结构的综合评价方法,观察香烟烟雾暴露对COPD大鼠气道纤毛结构的影响.方法 Wister大鼠,随机分为对照组(5只)、香烟暴露组(5只),香烟暴露组通过45 d被动吸烟建立COPD大鼠模型,利用光镜观察肺组织病理学变化,电镜观察纤毛超微结构改变,免疫荧光标记技术观察纤毛超微结构中微管蛋白变化.结果 香烟暴露组大鼠的纤毛荧光强度为(53.46±13.28),低于对照组(120.00±26.86)(P＜0.05).香烟暴露组纤毛膜水疱数为(7.36±2.38)个高于对照组(O.66±1.21)个(P＜0.05).结论 被动吸烟导致COPD大鼠气道纤毛结构异常,表现为纤毛膜水疱数增加、纤毛荧光强度减低.     

砷和香烟烟气溶液对氧化应激的协同作用

目的研究亚砷酸钠和香烟烟气溶液联合作用对大鼠淋巴细胞氧化应激的影响，并探讨两者对氧化应激的影响是否存在交互作用。方法大鼠淋巴细胞分为4组：亚砷酸钠单独作用组、香烟烟气溶液单独作用组、两者联合作用组和对照组，染毒后用流式细胞术检测细胞内活性氧的含量，用微量荧光法检测细胞内丙二醛含量，用彗星实验检测细胞的DNA损伤，同时采用2×2析因设计研究两者的交互作用。结果亚砷酸钠单独作用组、香烟烟气溶液单独作用组和两者联合作用组细胞内的活性氧含量、丙二醛含量、彗星尾长和细胞拖尾率均高于对照组。析因设计分析结果表明两者对细胞内活性氧含量、丙二醛含量及彗星尾长的影响存在交互作用。结论亚砷酸钠和香烟烟气溶液对大鼠淋巴细胞氧化应激的影响存在交互作用，交互作用方式为协同作用。     

Prostacyclin prevents pulmonary endothelial cell apoptosis induced by cigarette smoke

RATIONALE: Impaired endothelial cell-dependent vasodilation, inflammation, apoptosis, and proliferation are manifestations of endothelial dysfunction in chronic obstructive pulmonary disease (COPD). Prostacyclin (PGI(2)) is a major product of the cyclooxygenase pathway with potent vasodilatory and antimitogenic properties and may be relevant to endothelial dysfunction in COPD. OBJECTIVES: To determine if PGI(2) expression is altered in smoking-related lung disease and if it may be protective in COPD-associated endothelial dysfunction. METHODS: We evaluated, by immunohistochemistry, Western blotting, and polymerase chain reaction, human emphysema tissue compared with normal tissue for expression of prostacyclin synthase (PGI(2)S). We examined the effects of cigarette smoke extract (CSE) and aldehyde components on eicosanoid expression in primary human pulmonary microvascular endothelial cells. Finally, we used a murine model of lung-specific PGI(2)S overexpression and in vitro studies to determine if PGI(2) expression has protective effects on cigarette smoke-induced endothelial apoptosis. MEASUREMENTS AND MAIN RESULTS: Human emphysema lung tissue exhibited lower PGI(2)S expression within the pulmonary endothelium than in normal lung. In vitro studies demonstrated that CSE, and in particular the alpha,beta unsaturated aldehyde acrolein, suppressed PGI(2)S gene expression, whereas CSE significantly induced the upstream mediators COX-2 and cytosolic phospholipase A2 in human pulmonary microvascular endothelial cells. Mice with lung-specific PGI(2)S overexpression exhibited less endothelial apoptosis after chronic smoke exposure. In vitro, iloprost exhibited protective effects on CSE-induced apoptosis. CONCLUSIONS: PGI(2) has protective effects in the pulmonary vasculature after acute and chronic cigarette smoke exposure. An imbalance in eicosanoid expression may be important to COPD-associated endothelial dysfunction.     

香烟烟雾对细胞生物学功能的影响

香烟烟雾中含有大量的化学有毒物质,其颗粒物和挥发性有机物可不同程度地造成炎症的产生、细胞毒性增加、染色体损伤和DNA链断裂,从而引起慢性阻塞性肺疾病、肺癌等疾病的发生.氧化应激机制是目前研究的热点.本文主要从吸烟与呼吸系统疾病、香烟烟雾对细胞的损伤机制、香烟烟雾对气道上皮细胞的作用三大方面对香烟烟雾对细胞生物学功能的影响进行综述,有助于呼吸道疾病的诊断和治疗.     

Role of TRPA1 and TRPV1 in the ROS-dependent sensory irritation of superior laryngeal capsaicin-sensitive afferents by cigarette smoke in anesthetized rats

BackgroundLaryngeal exposure to cigarette smoke (CS) evokes sensory irritation, but the mechanisms are largely unclear. The TRPA1 and TRPV1 receptors are two types of Ca²⁺-permeant channels located at the terminals of airway capsaicin-sensitive afferents. We investigated the mechanisms underlying the airway reflex evoked by laryngeal CS exposure in anesthetized rats.MethodsCS (7 ml) was delivered into a functionally isolated larynx, while the animals (n = 201) breathed spontaneously. Respiratory parameters were measured. All use of pharmacological agents involved pretreatment by laryngeal application.ResultsLaryngeal CS exposure immediately evoked a concentration-dependant apneic response that was unrelated to the nicotine content of the CS. This inhibition of breathing was abolished by bilateral sectioning of the superior laryngeal nerves (SLNs) or by perineural capsaicin treatment of the SLNs (selective blocking of capsaicin-sensitive afferent neural conduction), suggesting the involvement of superior laryngeal capsaicin-sensitive afferents in the reflex. The reflex apnea was significantly attenuated by N-acetyl-l-cysteine (antioxidant), EGTA (extracellular Ca²⁺ chelator) and BAPTA-AM (intracellular Ca²⁺ chelator), indicating the importance of reactive oxygen species (ROS) and Ca²⁺. This reflex apnea was also partially reduced by HC030031 (TRPA1 receptor antagonist) and capsazepine (TRPV1 receptor antagonist), and was nearly abolished by a combination of these two antagonists, suggesting a central role for the TRPA1 and TRPV1 receptors. Furthermore, the reflex apnea was attenuated by indomethacin (cyclooxygenase inhibitor); however, the attenuation by indomethacin was not increased by pretreatment with HC030031 or capsazepine, indicating that TRPA1 and TRPV1 receptor functionality is, at least in part, linked to cyclooxygenase metabolites.ConclusionsThe reflex apnea evoked by laryngeal CS requires activation of both TRPA1 and TRPV1 receptors, which are likely to be located at the terminals of superior laryngeal capsaicin-sensitive afferents. Laryngeal sensory irritation by CS seems to depend on the actions of ROS and cyclooxygenase metabolites on these two types of receptors.     

Nose-only cigarette smoke exposure plus airway lipopolysaccharide inhalation induced chronic obstructive pulmonary disease and associated pulmonary hypertension in mice

<正>Objective To establish a mouse model of chronic obstructive pulmonary disease(COPD)and associated pulmonary hypertension(COPD-PH)induced by noseonly cigarette smoking exposure plus airway lipopolysaccharide(LPS)inhalation.Methods There were 24 male C57B6 mice divided into a control group and a model     

香烟烟雾刺激诱导肺动脉高压动物模型的构建

目的 探讨利用单纯香烟烟雾刺激造模能否有效构建肺动脉高压疾病模型.方法 把20只清洁级SD大鼠,随机分为对照组(9只)、肺动脉高压(模型)组(11只),用香烟烟雾刺激的方法诱导肺动脉高压模型.在造模满4个月时检测各组大鼠血流动力学指标,取肺组织制作病理切片,比较两组大鼠的肺血管重构程度.结果 与对照组相比,模型组右室收...     

急性烟雾吸入性肺损伤药物治疗的研究进展

烟雾吸入是火灾中受害者死亡的最主要原因.烟雾中的颗粒物、有毒气体、刺激剂以及窒息剂的共同作用,使肺部发生急剧的病理生理反应,造成急性肺损伤,进而导致人员大量伤亡.近20年来,对烟雾吸入性急性肺损伤的病理生理学机制有了比较清楚的认识,药物治疗方面也取得了较大的进展,本文对此作一综述.     

急性烟雾吸入性肺损伤药物治疗的研究进展

烟雾吸入是火灾中受害者死亡的最主要原因。烟雾中的颗粒物、有毒气体、刺激剂以及窒息剂的共同作用,使肺部发生急剧的病理生理反应,造成急性肺损伤,进而导致人员大量伤亡。近20年来,对烟雾吸入性急性肺损伤的病理生理学机制有了比较清楚的认识,药物治疗方面也取得了较大的进展,本文对此作一综述。     

Pattern of inhalation of tobacco smoke in pipe, cigarette, and never smokers

There is controversy on whether both primary and secondary pipe smokers do inhale tobacco smoke. We studied inhalation of tobacco smoke in 6 primary and 6 secondary pipe smokers and compared it with that in 20 cigarette smokers and 11 never smokers. Respiratory movements were assessed with inductive plethysmography, nasal flow through measurements of nasal pressure, oral flow with an oral thermistor, puffing through pressure measurements in the cigarette holder or the pipe, and upper airways by fluoroscopy. In all pipe smokers except 1, breathing and smoking appeared as independent activities. The former was exclusively nasal, whereas the latter was exclusively oral. Smoke was sucked and puffed by a to-and-fro movement of the tongue sliding along the soft palate. The oropharyngeal isthmus was closed (or only intermittently opened) by the apposition of the soft palate and the tongue, thus preventing overt inhalation of smoke. In most cigarette smokers, smoking interfered with the breathing route. Once smoke was sucked into the mouth, the oropharyngeal isthmus opened and inspiration proceeded through both mouth (with inhalation of smoke) and nose. Cigarette smoking interfered also with the evenness of ventilation. Never smokers avoided inhalation by oropharyngeal closure followed by oral expiration. We conclude that the oropharyngeal isthmus is the essential gate controlling smoke inhalation. Most secondary pipe smokers are able to change their smoking pattern and avoid overt inhalation when switching from cigarette to pipe smoking. The inhalation pattern appears to be acquired in the course of the smoking history.     

Lung phagocyte recruitment and metabolic alterations induced by cigarette smoke in humans and in hamsters

Cigarette smokers had an increased number of alveolar macrophages (AM) that had temporally related increases in oxidative metabolism in vitro compared with that in nonsmokers. The AM from young asymptomatic human cigarette smokers had a selective increase in superoxide anion (O2) release compared with those from nonsmokers. The AM from older smokers had a more intense, generalized enhancement of oxidative metabolism. Smoking hamsters had similar patterns of lung phagocyte recruitment and increased macrophage oxidative metabolism. The accumulation of AM within the alveolar ducts in smoking hamsters was strikingly similar to that seen in human smokers. The temporal patterns of smoke-induced changes in oxidative metabolism by AM from hamsters and humans were the same. Filtration of particulate constituents from cigarette smoke completely abrogated the distal airway inflammation and the metabolic alterations observed in smoking hamsters.     

砷和香烟烟气溶液联合作用对大鼠淋巴细胞凋亡的影响

目的研究亚砷酸钠和香烟烟气溶液(CSS)联合作用对Wistar大鼠淋巴细胞凋亡的影响。方法按2×2析因设计将大鼠淋巴细胞分为4组:对照组、亚砷酸钠组、CSS组、联合作用组。磷脂酰丝氨酸外翻分析法检测各组细胞凋亡情况.并检测各组细胞的Alamar Blue还原率以反映细胞生长代谢情况。结果亚砷酸钠组(1043.47±55.25)、CSS组(1186.52±48.90)和联合作用组(1650.64±89.65)凋亡细胞数明显高于对照组(861.22±42.67,P<0.05);各染毒组的细胞Alamar Blue还原率均明显低于对照组(P<0.05)。析因设计方差分析结果表明亚砷酸钠和CSS对细胞凋亡具有协同式交互作用(F=10.39,P<0.05);而二者对细胞Alamar Blue还原率的影响未见交互作用(F=0.00,P>0.05)。结论亚砷酸钠和CSS均促进大鼠淋巴细胞凋亡,并存在协同式交互作用。