活性氧对尘肺患者肺泡巨噬细胞凋亡信号转导途径的作用

目的 探讨活性氧(ROS)对Fas/FasL信号转导途径致肺泡巨噬细胞凋亡作用.方法 以中国北戴河煤炭工人疗养院无其他肺部疾病的Ⅰ期、Ⅱ期尘肺患者共45例为研究对象,将支气管肺泡灌洗液(BALF)中的肺泡巨噬细胞(AM)分两组培养,即对照组、超氧化物歧化酶(SOD)组.采用TUNEL技术检测AM凋亡情况,琼脂糖凝胶电泳法检测DNA片段,Western blot法检测AM的Fas、FasL、caspase 8、caspase 3表达水平.结果 SOD组的凋亡指数(9.50±2.76)显著低于对照组(19.18±2.83,P< 0.05);SOD组的Fas、FasL、caspase 8、caspase 3蛋白表达水平(分别为0.107±0.065、0.115±0.047、0.231±0.139、0.312±0.114)均低于对照组(分别为0.209±0.084、0.210±0.097、0.374±0.071、0.441±0.095,P<0.05);对照组出现凋亡细胞特征性"梯状带",而SOD组未出现.结论 Fas/FasL信号转导途径介导的AM凋亡可能与ROS上调Fas/FasL系统的表达有关.     

Vitamin E suppresses the induction of reactive oxygen species release by lipopolysaccharide, interleukin-1beta and tumor necrosis factor-alpha in rat alveolar macrophages

Over the last decade, although investigations have suggested that vitamin E affects the immune response, not much is known about its affect on the alveolar macrophage functions. In the present study, we have investigated the effect of high vitamin E (DL-alpha-tocopheryl acetate, alpha-TA) supplementation for 10 d on the activation state of rat alveolar macrophages induced by lipopolysaccharide (LPS), interleukin (IL)-1beta or tumor necrosis factor (TNF)-alpha on the basis of their ability to produce reactive oxygen species (ROS), such as superoxide (O2-*) and H2O2. LPS treatment (1 and 10 microg/mL) caused 2.44 and 2.54-fold increases in O2-*, and 2.1 and 2.3-fold increases in H2O2, respectively, from alveolar macrophages (AMs) in the diet group fed 50 mg alpha-TA/kg. However, this enhancement was not observed for the AMs of the diet groups fed 250 or 1,250 mg alpha-TA/kg. Similar results were obtained on treating the AMs with proinflammatory cytokines IL-1beta or TNF-alpha. The observed suppression in ROS release in response to various stimulants may be due to the direct and/or indirect effect of high vitamin E (250 and 1,250 mg alpha-TA/kg diet) supplementation. It may therefore, be concluded that high alpha-TA supplementation in the diet modulates the activation of AMs in rats.     

矽肺肺泡巨噬细胞对人胚肺成纤维细胞Ⅰ型胶原表达的体外研究

目的探讨矽肺患者的肺泡巨噬细胞(AM)是否通过影响肺成纤维细胞(FB)胶原的表达,参与矽肺纤维化的发生发展。方法收集矽肺患者AM,经SiO_2体外刺激18 h收集培养上清,与人胚肺FB共同孵育6、12、18、24、36、48、72 h,用~3H-脯氨酸掺入检测48 h胶原的合成与分泌,免疫细胞化学方法、Western blot方法检测各时间点Ⅰ型胶原表达。结果经SiO_2刺激矽肺患者AM培养上清,可使FB中Ⅰ型胶原的表达增高,实验组48 h细胞内、外3H-脯氨酸掺入值分别为1259.500±73.879、790.500±70.315,免疫细胞化学染色的积分光密度值为0.341±0.011,Western blot条带扫描灰度值为14.218±0.342,均明显高于空白对照组及AM对照组,差异有统计学意义(P<0.05或P<0.01)。结论SiO_2可通过AM介导影响FB中Ⅰ型胶原表达,参与肺纤维化的形成。     

矽肺病患者肺泡巨噬细胞死亡受体表达及意义

目的 探讨矽肺病患者肺泡巨噬细胞(AM)死亡受体(DR)的表达水平及其与肺纤维化程度的关系.方法 以61例进行肺灌洗的汉族男性观察对象及矽肺病患者为观察组,以13例肺部X射线表现完全正常的汉族男性为对照组,分离、纯化及培养各研究对象的AM,检测3种DR[凋亡蛋白-1(Fas)、肿瘤坏死因子受体-1(TNFR1)和肿瘤坏死因子相关凋亡诱导配体受体-2]的表达水平,采用酶联免疫吸附试验检测AM培养上清中的可溶性DR(sDR)水平,采用免疫印迹法检测AM裂解液中3种膜结合型DR(mDR)水平,分析DR表达水平与粉尘接触各因素的关系.结果 矽肺病患者膜结合型Fas(mFas)及膜结合型TNFR1(mTNFR1)的相对水平均高于对照组及观察对象(P＜0.05),且随着肺部病变的加重而升高;矽肺病患者可溶性Fas(sFas)及可溶性TNFR1(sTNFR1)水平均低于观察对象(P＜0.05),且sFas随着肺部病变的加重而下降.结论 矽尘诱导的mFas和mTNFR1表达上调、sFas表达下调在矽肺病发病及进展中起重要作用,DR信号通路活化可能是矽肺病发病的重要机制之一.     

Biological effects of man-made mineral fibers (I)--Reactive oxygen species production and calcium homeostasis in alveolar macrophages

10 types of standard mineral fiber samples (JFM fibers) were tested for their cytotoxicity in alveolar macrophages (AM) in vitro experiments, in which UICC chrysotile B was used as a positive control. The cytotoxicity included the production of superoxide anion radical and hydrogen peroxide, depletion of glutathione (GSH) and increase of intracellular free calcium. The results showed that chrysotile and most of the 10 mineral fibers could increase the production of superoxide anion and hydrogen peroxide, deplete the concentration of GSH and increase the level of free intracellular Ca2+ in AM. But all the effects of JFM fibers were lower than that induced by UICC chrysotile B. Although the cytotoxicity of JFM fibers were lower than that of asbestos, these mineral fibers should be used with highly care for workers in industries.     

SiO2对血小板源性生长因子蛋白表达及胶原合成的影响

目的 探讨siO2刺激矽肺患者的肺泡巨噬细胞(AM)及其介导的人胚肺成纤维细胞(HELF)血小板源性生长因子(PDGF)的蛋白表达及胶原合成.方法 收集矽肺患者AM,体外经SiO2刺激3、6、12、18、24、36 h,收集培养上清,用ELISA法检测AM上清中PDGF的蛋白表达,用其表达峰值时的培养上清与HELF共同孵育6、12、18、24、36、48 h,用免疫细胞化学法及Western blot法分别检测HELF及其培养上清中PDGF的蛋白表达情况,用3H-脯氨酸掺入法检测HELF胶原的合成与分泌情况.结果 经SiO2刺激的矽肺患者AM条件上清中PDGF的蛋白表达量在作用24 h时最高(平均吸光度值为0.282±0.019),与同期对照组(平均吸光度值为0.214±0.014)相比,差异有统计学意义(P<0.01). 用AM上清作用于HELF后,HELF细胞内及其培养上清中PDGF的蛋白表达均升高,与对照组比较,HELF培养上清中PDGF蛋白表达于12、18、24、36、48 h时明显增高,HELF中PDGF蛋白表达于18、24、36、48 h时明显增高,差异均有统计学意义(P<0.05).矽肺患者AM培养上清与HELF共同孵育不同时间后,HELF细胞内及培养上清中胶原明显增加.结论 SiO2通过AM的介导影响了HELF中PDGF的蛋白表达与胶原合成及分泌.     

矽肺肺泡巨噬细胞对肺成纤维细胞基质金属蛋白酶及其抑制因子和胶原表达的影响

目的 探讨经SiO2刺激的肺泡巨噬细胞(AM)通过人胚肺成纤维细胞(HELF)对基质金属蛋白酶-1(MMP-1)及其抑制因子(TIMP-1)和Ⅲ型胶原表达的影响.方法 收集矽肺患者AM,将其分为加入SiO2粉尘悬液的处理组和仅加入无血清培养液的对照组.培养18 h后吸出培养上清.将原代培养的HELF分为4组:(1)处理组:加入经SiO2刺激的AM上清;(2)对照组:加人未经SiO2刺激的AM上清;(3)10%血清组:仅加入含体积分数为10%胎牛血清的DMEM;(4)空白对照组:仅加入含体积分数为3%胎牛血清的DMEM.4组均分别于6、12、18、24、36、48 h取出细胞爬片,吸出上清,用免疫细胞化学方法 检测HELF中MMP-1和TIMP-1的表达,用Western blot法检测HELF条件培养上清中Ⅲ型胶原的表达.结果 处理组18、24、36、48 h MMP-1表达分别为0.0605±0.0201,0.0519±0.0117,0.0412±0.0105,0.0213±0.0106,较对照组和空白对照组明显降低,差异均有统计学意义(P<0.05,P<0.01).与对照组和空白对照组相比,处理组各时间点TIMP-1表达和Ⅲ型胶原含量明显增高,差异均有统计学意义(P<0.05,P<0.01),TIMP-1/MMP-1与Ⅲ型胶原呈正相关(r=0.88,P<0.01).结论 SiO2经AM的介导可促进FB表达TIMP-1和Ⅲ型胶原,抑制HELF表达TIMP-1,TIMP-1/MMP-1的失衡与Ⅲ型胶原的病理性累积有关.     

Toxicity of penicillic acid for rat alveolar macrophages in vitro

Penicillic acid (PA) is a polyketide mycotoxin produced by several species of Aspergillus and Penicillium. This mycotoxin is toxic in experimental animals and has also been reported to be carcinogenic. The cytotoxicity of penicillic acid was studied in rat alveolar macrophages (AM) in vitro. The effects of penicillic acid on membrane integrity were studied by measuring cell volume changes and 51Cr release. There was significant 51Cr release after 2 hr exposure to 1.0 mM penicillic acid, but not after 1 hr exposure. There was a significant decrease in adenosine triphosphate (ATP) in cell cultures exposed to 1.0 mM penicillic acid for 4 hr. Inhibition of the incorporation of [3H]leucine into protein was both dose- and time-dependent and protein synthesis was inhibited significantly after 2 hr exposure to greater than or equal to 0.1 mM penicillic acid. RNA synthesis was inhibited to a lesser extent than protein synthesis. Although there was a significant inhibition of RNA synthesis at 1.0 mM PA after 4 hr, there was no inhibition of RNA synthesis even after 4 hr at any concentration less than 1.0 mM. The ED50 dose after 2 hr exposure was 0.18 and 0.60 mM for protein and RNA synthesis, respectively. There was significant inhibition of phagocytosis after 2 hr exposure at greater than or equal to 0.3 mM penicillic acid and the ED50 for phagocytosis was 0.09 mM. Thus phagocytosis was more sensitive to the toxic effects of penicillic acid than any other cellular process studied. The results reported in this study are similar to those observed for patulin in an earlier study from our laboratory except that patulin was generally more toxic to alveolar macrophages than penicillic acid. The data demonstrate that penicillic acid is toxic to rat alveolar macrophages in vitro and suggest the possibility of a respiratory hazard to agricultural workers exposed to contaminated grain.     

石英对大鼠肺上皮细胞和成纤维细胞的增殖抑制及致hprt基因突变的研究

目的探讨石英对大鼠肺泡II型上皮细胞和成纤维细胞的增殖抑制及致hprt基因突变的差异。方法采用(MTT噻唑蓝)比色法检测大鼠肺成纤维细胞和肺泡II型上皮细胞的增殖抑制毒性。以含6-巯基鸟嘌呤(6-TG)的培养基筛选突变细胞克隆,检测hprt基因突变频率。结果在相同的染毒条件下,肺泡II型上皮细胞对石英刺激比成纤维细胞更易受损伤,上皮细胞半数增殖抑制浓度(IC50)约为140μg/cm2,成纤维细胞的IC50约为282μg/cm2。在致hprt基因突变方面,石英粉尘对两种细胞都有致突变作用。在同样剂量染毒条件下,肺泡Ⅱ型上皮细胞的hprt突变频率为84.2×10-6～156.6×10-6,较成纤维细胞(67.6×10-6～114.3×10-6)更容易发生hprt基因突变,差异有显著性(P<0.05)。结论石英对大鼠肺成纤维细胞和肺泡II型上皮细胞的细胞毒性及对hprt基因致突变作用强度存在明显差异。肺泡II型上皮细胞对石英刺激的反应敏感性高于成纤维细胞。     

尘肺患者肺泡巨噬细胞凋亡及其死亡信号调控机制研究

目的初步研究尘肺患者肺泡巨噬细胞(AM)的凋亡情况以及肿瘤坏死因子-α及其受体(TNF-α/TNFR)信号通路对AM凋亡的调控作用,为尘肺病的早期防治提供依据。方法选取30例尘肺患者为研究对象,收集其肺泡灌洗回收液,分离纯化AM,将实验分为5组,即未处理组、超氧化物歧化酶(SOD)组、TNF-α/TNFR组、抗-TNF-α组、半胱氨酰天冬氨酸特异蛋白(Caspase)-8抑制剂组。培养24h后,收获AM,分别用光学显微镜、透射电子显微镜、荧光共聚焦显微镜检测AM凋亡的情况。采用SAS8.2软件进行方差分析和2分析。结果光学显微镜、荧光共聚焦显微镜、透射电镜下均可见凋亡细胞染色质浓缩、边缘化、染色质分割成块状、核膜不完整和凋亡小体等典型的凋亡形态。SOD组、抗-TNF-α组、Caspase-8抑制剂组的AM凋亡指数均低于未处理组。结论尘肺患者AM存在一定程度的凋亡,表现为形态学的改变,凋亡程度与接尘性质有关,与尘肺期别、接尘工龄、脱尘年限无关。SOD复合酶、抗-TNF-α抗体、Caspase-8抑制剂可在信号通路的不同环节阻断信号转导,抑制AM凋亡的发生。     

矽肺肺泡巨噬细胞对肺成纤维细胞基质金属蛋白酶及其组织抑制因子表达的影响

目的 探讨矽肺患者的肺泡巨噬细胞(AM)是否通过影响肺成纤维细胞(FB)基质金属蛋白酶(MMPs)/金属蛋白酶组织抑制因子(TIMPs)系统参与矽肺纤维化的发生发展。方法 收集矽肺患者AM培养上清,与人胚肺FB共同孵育6、12、18、24、36、48 h,用免疫细胞化学的方法检测FB中MMP-1和TIMP-1的表达。结果 未经SiO2刺激的矽肺患者AM培养上清作用于FB 24 h,FB中MMP-1的表达较空白对照组减少(积分光密度值分别为0.103±0.014、0.133±0.023),TIMP-1的表达增多(积分光密度值分别为0.108±0.012、0.065±0.006);经SiO2刺激24 h的矽肺患者AM培养上清作用于FB后,FB中MMP-1的表达量进一步减少(积分光密度值分别为0.062±0.008、0.133±0.023),而TIMP-1的表达量进一步增加(积分光密度值分别为0.143±0.015、0.065±0.006)。结论 SiO2可能通过AM的介导影响了FB中MMP-1/TIMP-1系统的表达,参与了肺纤维化的形成。     

Effect of zinc and copper deficiency on microsomal NADPH-dependent active oxygen generation in rat lung and liver

Both dietary zinc and copper deficiencies can cause lipid peroxidation in microsomes in rats. The cytochrome P-450 enzyme system can generate active oxygens by uncoupling of the P-450-oxy complex in the catalytic cycle and/or the electron transfer mediated by the NADPH-cytochrome P-450 reductase. The effects of dietary zinc and copper deficiencies on NADPH-dependent H2O2 generation, the catalytic activity of the cytochrome P-450 enzyme with aminopyrine as the substrate and the activity of NADPH-cytochrome P-450 reductase were determined. Zinc deficiency caused increased H2O2 production, increased NADPH-cytochrome P-450 reductase activity, decreased aminopyrine demethylation and two- and fivefold increases in iron concentration in lung and liver microsomes, respectively, compared to Zn-adequate, ad libitum--fed controls. Active oxygen generation by uncoupling of the cytochrome P-450 enzyme system and accumulation of iron are thus possible mechanisms by which zinc deficiency causes microsomal lipid peroxidation. Copper deficiency did not affect H2O2 production; however, it caused two- and fourfold increases in iron concentration in lung and liver microsomes, respectively, compared to Cu-adequate, ad libitum--fed controls. The mechanism by which cooper deficiency causes microsomal lipid peroxidation is still unknown but could be related to the observed accumulation of iron.     

Study on the interaction of ions of transient metals with ascorbic acid in the presence of different scavengers of active oxygen species in SOS chromotest

SOS chromotest was employed to study the interaction of ascorbic acid with free ions of transient metals in the presence of added catalase, superoxide dismutase or D-mannitol. Catalase diminished the genotoxic activity of the mixture of ascorbic acid with copper ions in E. coli strains PQ37 and PQ 300, but genotoxicity of this mixture was not suppressed by superoxide dismutase and D-mannitol. The results suggest that copper ions diminished the content of peroxide generated by ascorbic acid.     

Effects of active oxygen species on damage to and prostaglandin synthesis in cultured rat gastric cells.

Active oxygen species cause gastric mucosal damage in vivo. However, it is not known if these species are directly cytotoxic toward gastric cells. Prostaglandins have important physiological roles in the gastric mucosa, including direct cell protection against damaging factors. So, to find if active oxygen species affect prostaglandin synthesis in gastric mucosal cells is important, but this also is not known. This study was done to investigate the effects of such species on damage to and prostaglandin synthesis in cultured mucus-producing cells from rat gastric mucosa. Active oxygen species were produced by the addition of xanthine and xanthine oxidase to the culture medium. Cytotoxicity was assayed by 51Cr release. Xanthine (1 mM) and xanthine oxidase (100 mU/ml) increased specific 51Cr release as the thiobarbituric acid reactants increased. This increase in 51Cr release was inhibited by catalase, a scavenger of hydrogen peroxide, or dimethyl sulfoxide, a scavenger of hydroxyl radicals, but not by superoxide dismutase, a scavenger of superoxide, nor deferoxamine, an inhibitor of hydroxyl radical generation. Catalase, dimethyl sulfoxide, and superoxide dismutase each had no effect on prostaglandin E2 synthesis when xanthine and xanthine oxidase were not added. In the presence of xanthine and xanthine oxidase, catalase and dimethyl sulfoxide stimulated the synthesis of prostaglandin E2 and superoxide dismutase inhibited it. Indomethacin, a prostaglandin synthetase inhibitor, did not affect the decrease in 51Cr release caused by catalase in the presence of xanthine and xanthine oxidase, but it abolished the decrease caused by dimethyl sulfoxide. These results suggest that hydrogen peroxide, but not superoxide nor hydroxyl radicals, is involved in damage to cultured rat gastric cells, and that superoxide stimulates prostaglandin E2 synthesis, but that hydrogen peroxide inhibits it. Protection of the cells by dimethyl sulfoxide may be related to stimulation of prostaglandin E2 synthesis in the cells, but not via scavenging hydroxyl radicals.     

Enhanced phagocytosis of rat alveolar macrophages by intravenous infusion of an arginine-enriched solution.

Phagocytosis of rat alveolar macrophages (AM) was enhanced by the infusion of arginine-rich solution for 7 days. The enhancement of phagocytosis by arginine-rich solution was due to not the difference in the distribution of AM subpopulations (I to IV) but the difference in phagocytic activity of AM in fraction IV. In the process of phagocytosis, there were no significant differences in the stages of migration, attachment, and digestion between control and arginine-rich solutions, although AM from fraction IV of rats infused with arginine-rich solution showed significantly higher ingestion of opsonized sheep red blood cells (SRBC) compared to that of control group. Furthermore, the production of macrophage-activating factor (MAF) from rat splenocytes was higher in arginine-rich group than that of control group. AM from fraction IV of rats fed a stock diet had a higher arginase activity and showed a significant increase of phagocytosis following in vitro incubation with L-arginine (25 and 50 mM) for 24 h. From these results, the enhanced phagocytosis of AM by arginine-rich solution may be due to the increased phagocytosis of AM from fraction IV, in which the higher sensitivity of AM from fraction IV to arginine and the higher production of MAF from splenocytes following the infusion of arginine-rich solution participate.     

Involvement of oxidative stress in crystalline silica-induced cytotoxicity and genotoxicity in rat alveolar macrophages

Alveolar macrophages (AMs) occupy a key position in silica-induced pulmonary fibrosis, although the mechanisms are yet to be elucidated. In the present study we examined the involvement of oxidative stress and reactive oxygen species formation in silica-induced cytotoxicity and genotoxicity in cultured rat AMs. A lucigenin-dependent chemiluminescence test was used to determine superoxide anion (O(-)(2)), and a 2',7'-dichlorofluorescin diacetate fluorescence test was employed to measure the hydrogen peroxide (H(2)O(2)) level. The cytotoxic and genotoxic effects caused by silica in AMs were examined by lactate dehydrogenase (LDH) leakage and single-cell gel electrophoresis (comet assay), respectively. The results showed that silica enhanced O(-)(2) and H(2)O(2) formation in AMs. There were clear dose- and time-dependent relationships in silica-induced cytotoxicity and genotoxicity. Furthermore, superoxide dismutase and catalase were able to reduce silica-induced LDH leakage and DNA damage, with concurrent significant inhibition on silica-induced oxidative stress in AMs. These findings provide convincing evidence that oxidative stress mediates the silica-induced cytotoxicity and genotoxicity. The understanding of such a mechanism may provide a scientific basis for the possible application of antioxidants in preventing the hazardous effects of silica.     

Effects of active oxygen scavengers on the peroxidation of linoleic acid catalyzed by dehydro-L-ascorbic acid or its degradation products

The addition of 1,4-diazabicyclo-[2,2,2]octane (DABCO) (100 mM) or 1,2-dihydroxybenzene-3,5-disulfonic acid (Tiron) (1 mM) to a reaction mixture containing 10 mM linoleic acid (LA), 20% EtOH, and 135 microM dehydroascorbic acid (DHA) as a catalyst suppressed LA peroxidation, but the addition of mannitol (approximately 100 mM), uric acid (100 microM), and catalase (6.5 units) did not. DHA or 2,3-diketo-L-gulonic acid (DKG) accelerated LA peroxidation, but the splitting products of DHA did not affect LA peroxidation. These results suggest that some specific radicals are liberated in the degradation of DHA or DKG.     

SiO_2刺激矽肺肺泡巨噬细胞上清介导的人胚肺成纤维细胞基质金属蛋白酶-2/9的表达

目的 探讨SiO_2体外刺激矽肺患者的肺泡巨噬细胞(AM)培养上清对人胚肺成纤维细胞(HELF)基质金属蛋白酶(MMP)-2/9的表达的影响.方法 将矽肺患者的AM在体外经SiO_2刺激24 h后收集其培养上清,与HELF共同孵育12、24、36、48、72 h,用免疫细胞化学方法检测各时间点HELF中MMP-2/9蛋白表达;明胶酶谱法检测各时间点HELF培养液的MMP-2/9活力的表达.结果 经SiO_2刺激后,实验组HELF在24、36、48、72 h MMP-2活力的表达增强,分别为1.572±0.104、1.786±0.125、1.987±0.130、2.147±0.156,与同期对照组相比,差异有统计学意义(P<0.05).实验组HELF在24、36、48、72 hMMP-9活力的表达增强,与同期对照组相比,差异有统计学意义(P<0.01).实验组HELF在24、36、48、72 h MMP-2蛋白的表达增强,分别为0.171±0.018、0.200±0.018、0.221±0.023、0.212±0.020,与同期对照组相比,差异有统计学意义(P<0.05);实验组HELF在24、36、48、72 h MMP-9蛋白的表达增强,与同期对照组相比,差异有统计学意义(P<0.05).结论 SiO_2可通过AM介导促进HELF中MMP-2和MMP-9蛋白及活力表达.     

Dissolution of metals by human and rabbit alveolar macrophages

The ability of human and rabbit alveolar macrophages to dissolve 0.1-0.5 micron MnO2 particles in vitro was compared. The amount of Mn added and dissolved from the particles over periods of nought, one, and three days was determined by flame atomic absorption spectrophotometry. The amount dissolved by human and rabbit macrophages was similar; on average 43.1% and 43.9%, respectively, were dissolved within three days. But rabbit and human macrophages dissolved significantly more Mn than was dissolved in the respective culture medium without macrophages after one and three days. It is suggested that the dissolution of particles by alveolar macrophages should be one basic component in any model of alveolar clearance of inorganic particles.