脂多糖对衰老大鼠肺泡巨噬细胞分泌细胞因子的影响

目的探讨脂多糖(lipopolysaccharide,LPS)对衰老大鼠模型肺泡巨噬细胞(alveolar macrophage,AM)产生细胞因子的影响。方法①将24只Wistar大鼠随机均分为2组,任取其中1组用D-半乳糖[D-galac-tose,D-gal,20mg/(kg.d)]腹腔注射,连续6周制备衰老大鼠模型;另1组青年大鼠作为对照;②应用支气管肺泡灌洗和细胞贴壁的方法获取AM,用瑞氏染色鉴定纯度、台盼蓝染色测定活细胞数;③将各组获取的AM再随机均分为LPS刺激组及阴性对照组,其中LPS刺激组细胞在贴壁2h后加入含10mg/L LPS的1640培养液,24h后用酶联免疫吸附法(enzyma linked immunosorsent assay,ELISA)分别测定细胞上清液中肿瘤坏死因子-α(tumor necrosis fac-tor-α,TNF-α)和内皮素(endolthelin,ET-1)的含量。结果(1)青年、老年大鼠LPS刺激组TNF-α、ET-1均高于对照组;(2)老年LPS刺激组肺泡灌洗液上清中TNF-α[(31.32±2.38)pg/ml]高于青年LPS刺激组[(25.48±3.52)pg/ml,P<0.05];老年LPS刺激组ET-1[(3.91±0.11)pg/ml]高于青年LPS刺激组[(3.17±0.11)pg/ml,P<0.05]。结论老年大鼠对LPS刺激的反应程度大于青年组,AM在炎症反应中起重要的作用。     

肺泡巨噬细胞一氧化氮及其在肿瘤发生中的作用

肺内多种细胞都有一氧化氮合酶存在，肺泡巨噬细胞表达ｉＮＯＳ。多种细胞因子及脂多糖可诱导肺泡巨噬细胞合成大量一氧化氮。由活化巨噬细胞产生的ＮＯ是其杀伤肿瘤细胞的中心效应分析，ＮＯ主要是与瘤ＤＮＡ合成酶及线粒体呼吸链中酶活性部位Ｆｅ－Ｓ基团作用，形成亚硝酰基复合物。引起酶的活性丧失与破坏，从而抑制瘤细胞的能量代谢与ＤＮＡ复制，导致细胞生长抑制甚至死亡。ＮＯ杀瘤作用的发现可能将为肿瘤治疗带来新的线索和希     

巨噬细胞刺激蛋白对烟熏大鼠肺泡巨噬细胞氧化应激和细胞因子产生的影响

目的 探讨巨噬细胞刺激蛋白(MSP)对烟熏大鼠肺泡巨噬细胞氧化应激和细胞因子产生的影响.方法 培养正常和烟熏不同时间(1个月、2个月、3个月)的大鼠肺泡巨噬细胞,给予不同浓度MSP处理24 h,采用酶联免疫法检测细胞上清液中细胞因子肿瘤坏死因子α(TNF-α)、白介索8(IL-8)和IL-1β的浓度,比色法检测细胞上清液中丙二醛(MDA)和超氧化物歧化酶(SOD)的水平.结果 ①MSP呈浓度依赖性促进正常组和各烟熏组大鼠肺泡巨噬细胞分泌TNF-α、IL-8和IL-1β;经MSP处理后,各烟熏组大鼠肺泡巨噬细胞上清液中TNF-α、IL-8和n-1β浓度均高于正常组(P＜0.05);大鼠肺泡巨噬细胞上清液中TNF-α、IL-8和IL-1β浓度随烟熏时间延长呈时间依赖性增加.②MSP呈浓度依赖性促进正常组和各烟熏组大鼠肺泡巨噬细胞分泌MDA,抑制其产生SOD;烟熏2个月组和烟熏3个月组大鼠肺泡巨噬细胞上清液中MDA水平均高于正常组(P＜0.05),SOD水平均低于正常组(P＜0.05);随着烟熏时间延长,大鼠肺泡巨噬细胞上清液中MDA水平呈时间依赖性增加,SOD水平呈时间依赖性降低.结论 MSP呈浓度依赖性促进正常和烟熏大鼠肺泡巨噬细胞分泌TNF-α、IL-8、IL-1β和MDA,抑制其产生SOD.MSP促烟熏大鼠肺泡巨噬细胞分泌TNF-α、IL-8、IL-1β、MDA及抑制其产生SOD的作用较正常大鼠更显著,且烟熏时间越长此作用越明显.     

过氧化还原蛋白6对细菌脂多糖诱导的小鼠急性肺损伤氧化应激的保护作用

目的探讨过氧化还原蛋白Peroxiredoxin(Prdx)6对细菌脂多糖(LPS)诱导的小鼠急性肺损伤氧化应激的作用及机制。方法应用PCR法对Prdx6基因敲除小鼠行基因型鉴定并应用免疫组织化学法测定Prdx6蛋白在肺脏的表达。将雄性Prdx6基因敲除型小鼠（18只）按随机数字表法分入Prdx6敲除型对照组（9只）、Prdx6敲除型LPS 24 h组（9只）;将雄性野生型C57BL/6J小鼠（18只）按随机数字表法分入野生型对照组（9只）、野生型LPS 24 h组（9只）。各LPS组小鼠气管滴注LPS(5 mg/kg)制备急性肺损伤模型,于给药后24 h分别行肺脏病理检测,BCA法测定BALF内蛋白浓度,比色法测定肺脏总超氧化物歧化酶(T-SOD)活力和过氧化氢、羰基化蛋白和总抗氧化能力(TAOC),TBA法测定丙二醛的表达。结果Prdx6基因敲除小鼠肺组织免疫组织化学法未检测到Prdx6蛋白表达。两种属小鼠LPS组肺脏病理可见炎症细胞浸润、肺泡间隔增厚及肺泡内出血,Prdx6敲除型较野生型小鼠病理损伤更重。LPS刺激后,野生型LPS 24 h组BALF内的蛋白浓度为(441±54) mg/L,高于野生型对照组的(168±20) mg/L(t=-4.71,P＜0.01);Prdx6敲除型LPS 24 h组为(770±66)mg/L,高于野生型LPS 24 h组（t=-3.69,P＜0.01）。野生型LPS 24 h组T-SOD为(16.0±1.2) U/mg,低于野生型对照组的(26.5±3.9) U/mg(t=-6.22,P＜0.01);Prdx6敲除型LPS24 h组为(14.5±5.3)U/mg,与野生型LPS 24 h组差异无统计学意义（t=-0.56,P=0.60）。野生型LPS 24 h组肺脏过氧化氢和丙二醛[分别为(52.3±7.8)nmol/g和(3.3±0.5)nmol/mg]高于野生型对照组[分别为(29.5±3.2)nmok/g和(1.6±0.8)nmol/mg],差异有统计学意义（t值分别为-4.25和-5.94,均P＜0.01）,Prdx6敲除型LPS 24 h组[分别为(73.5±12.4)nmol/g和(5.9±0.9)nmol/mg],均高于野生型LPS24 h组（t值分别为-3.01和-6.01,均P＜0.05）。野生型LPS24 h组肺脏蛋白羰基为(6.9±1.2)nmol/mg,与野生型对照组的(6.1±0.9)nmol/mg差异无统计学意义(t=-1.62,P=0.15);Prdx6敲除型LPS 24 h组为(8.9±0.9)nmol/mg,高于野生型LPS 24 h组(t=-2.76,P＜0.05)。野生型LPS 24 h组肺脏TAOC为(4.7±0.6) U/mg,低于野生型对照组的(6.5±0.4) U/mg(t =3.35,P＜0.01);Prdx6敲除型LPS 24 h组为(3.9 ±0.4) U/mg,低于野生型LPS24 h组(t =2.44,P=0.04)。Prdx6敲除型对照组与其野生型对照组以上参数表达差异无统计学意义。结论在LPS诱导的肺损伤中,Prdx6基因缺失增加了活性氧的产生,加重了氧化应激反应,从而使肺损伤恶化。     

脂多糖对大鼠肺泡巨噬细胞Toll样受体4和髓样分化蛋白-2基因表达及炎性因子分泌的影响

目的 探讨脂多糖刺激大鼠肺泡巨噬细胞株NR8383细胞Toll样受体4(TLR4)、髓样分化蛋白-2(MD-2)mRNA表达和炎性因子分泌的影响,以及MD-2小干扰RNA(MD-2 siRNA)对脂多糖刺激下NR8383细胞炎性因子分泌的作用.方法 体外培养NR8383细胞,以不同浓度脂多糖(0.01～10 mg/L)刺激2 h,以1 mg/L脂多糖刺激2～24 h.运用脂质体Lipofectamine 2000将MD-2siRNA转染至细胞.半定量RT-PCR方法检测细胞TLR4和MD-2 mRNA的表达,酶联免疫吸附法检测细胞培养上清中肿瘤坏死因子(TNF)-α、白细胞介素(IL)-6和IL-1β的含量.统计学处理采用单因素方差分析、独立样本t检验和Pearson相关分析.结果 对照组NR8383细胞TLR4和MD-2mRNA的相对表达量分别为0.52±0.05和0.44±0.09,0.01 mg/L浓度脂多糖刺激前后表达量无明显改变,0.1 mg/L浓度时表达增加,随脂多糖浓度的升高表达量进一步增加,10 mg/L刺激后相对表达量分别为0.72±0.06和0.65±0.10(F=17.26、6.04,P<0.01);TNF-αIL-6和IL-1β含量具有类似改变趋势,对照组分别为(25.8±3.4)ng/L、(62.4±4.7)ng/L和(31.6±1.7)ng/L;在10 mg/L脂多糖刺激下分别增加至(58.9±5.3)ng/L、(96.5±3.9)ng/L和(55.4±5.4)ng/L(F=29.55、54.47、31.45,P<0.01).在1 mr/L脂多糖刺激下,TLR4和MD-2 mRNA的表达量在2 h后明显增加,6 h达高峰,8 h开始回落,至24 h时仍高于基础值(F=5.28、4.11,P<0.01);TNF-α、IL-6和IL-1β含量具有类似变化(F=10.64、11.23、17.58,P<0.01),其中TNF-α和IL-1β含量在6 h达高峰,持续至8 h,IL-6含量在8 h达高峰,持续至12 h.TLR4和MD-2 mRNA表达呈正相关(r=0.513,P<0.01).MD-2 siRNA对NR8383细胞MD-2基因的干扰效率为67%,在脂多糖刺激下干扰组细胞培养上清液中TNF-α、IL-1β和IL-6水平未见明显升高.结论 高浓度脂多糖可较长时间上调大鼠肺泡巨噬细胞株NR8383细胞TLR4和MD-2基因的表达,并促进TNF-α、IL-6和IL-1β的分泌.MD-2 siRNA可抑制脂多糖刺激下NR8383细胞分泌TNF-α、IL-1 β和IL-6.     

吴茱萸次碱对氧化应激诱导血管平滑肌细胞增殖和一氧化氮合酶的影响

目的观察氧化应激对吴茱萸次碱作用血管平滑肌细胞增殖和一氧化氮合酶(NOS)的影响。方法血管平滑肌细胞分空白组、二甲基亚砜组、药物A组(吴茱萸次碱0.4μmol/L)、药物B组(吴茱萸次碱1μmol/L)、药物C组(吴茱萸次碱4μmol/L),后4组药物刺激2h后,加入过氧化氢诱导氧化应激损伤,24h后检测细胞增殖率、活性氧、丙二醛、超氧化物歧化酶(SOD)、内皮型NOS(eNOS)、诱导型NOS(iNOS)mRNA和蛋白表达。结果与空白组比较,二甲基亚砜组细胞增殖率明显升高[(104.48±4.89)%vs(94.58±1.87)%,P0.05],活性氧和丙二醛明显升高,SOD明显下降[(82.55±17.31)U/mg vs(111.76±18.25)U/mg,P0.05]。与二甲基亚砜组比较,药物A组、药物B组、药物C组细胞增殖率、活性氧和丙二醛明显下降,药物B组、药物C组SOD明显升高(P0.05);药物A组、药物B组、药物C组iNOS mRNA和蛋白表达明显下降,eNOS mRNA和蛋白表达明显升高(P0.05)。结论吴茱萸次碱在氧化应激状态下能抑制平滑肌细胞增殖、抗氧化、维持NOS相对稳定。     

肺纤维化大鼠巨噬细胞释放一氧化氮的研究

肺纤维化大鼠巨噬细胞释放一氧化氮的研究吕长俊赵洪文于润江侯显明在间质性肺疾病发生发展的病理过程中，包括一氧化氮（ＮＯ）在内的活性氧自由基是导致肺损伤的重要机制之一。我们研究了博莱霉素模型大鼠肺泡巨噬细胞（ＡＭ）和间质巨噬细胞（ＩＭ）释放的ＮＯ，并分别...     

吸烟大鼠肺组织和肺泡巨噬细胞一氧化氮合酶的表达及其与肺泡Ⅱ型上皮细胞Fas/FasL系统表达的关系

吸烟可引起呼吸道慢性炎症 ,使气道中炎症细胞增加 ,特别是肺泡巨噬细胞 (ＡＭ)明显增加 ,它可产生和释放许多细胞介质和酶引起呼吸道及肺泡组织结构损伤[1] 。Ｆａｓ/ＦａｓＬ是细胞凋亡的重要信号通路之一 ,炎症时Ｆａｓ抗原表达上调与靶细胞上配体ＦａｓＬ结合形成复合体而诱导靶细胞凋亡[2 ] 。我们就不同时期吸烟大鼠肺组织中原生型一氧化氮合酶 (ｃＮＯＳ)和ＡＭ诱生一氧化氮合酶 (ｉＮＯＳ)表达的变化来探讨其对肺泡Ⅱ型上皮细胞Ｆａｓ/ＦａｓＬ系统表达的影响。材料与方法　 (1)动物模型制作与分组 :健康Ｗｉｓｔａｒ大鼠 84只 ,体…     

胆囊收缩素对脂多糖刺激大鼠肺泡巨噬细胞的影响

八肽胆囊收缩素（CCK-8）对内毒素休克（ES）大鼠有保护作用,可能与抑制ES大鼠促炎性细胞因子过量生成有关.CCK-8可能与CCK受体结合干扰脂多糖（LPS）诱导肺泡巨噬细胞（AM）过度激活.     

内质网应激在PM2.5诱导大鼠肺泡巨噬细胞凋亡中的作用

目的 本研究通过用PM2.5干预传代培养的大鼠肺泡巨噬细胞,检测细胞存活率、凋亡率,及内质网应激信号分子C/EBP同源蛋白(C/EBP honologus protein,CHOP)、葡萄糖调节蛋白78 (glucoser regulated ptotein 78,GRP78)的mRNA相对表达量,探讨内质网应激在PM2.5诱导肺泡巨噬细胞凋亡过程中的作用.方法 用不同浓度的PM2.5干预传代培养的肺泡巨噬细胞(NR8383细胞),分6个浓度组(分别为H0:0 mg/L,空白对照组,加等体积的PBS液;H1:40 mg/L;H2:80 mg/L;H3:160 mg/L;H4:320 mg/L;H5:640 mg/L),经12h、24 h、48h3个时间后,用MTT法检测NR8383细胞的存活率,选择最佳的干预时间.将传代的NR8383细胞接种于6孔板,浓度组设置同MTT,每组设3个复孔(n=3),经最佳干预时间后,采用流式细胞术检测各浓度组细胞的早期凋亡率及总凋亡率,用RT-PCR法检测各浓度组CHOP mRNA、GRP78 mRNA的相对表达量.结果 PM2.5干预12 h后,H1组与H0组、H2组与H1组细胞存活率间的差异无统计学意义(P＞0.05),余组间差异有统计学意义(P＜0.05),且随干预浓度的增加,细胞存活率下降.干预24 h后,除H5组与H4组差异无统计学意义(P＞0.05),余各组细胞存活率的组间差异有统计学意义(P ＜0.05).干预48 h后,H4组与H3组及H5组与H4组差异无统计学意义(P＞0.05),余各组细胞存活率的组间差异有统计学意义(P ＜0.05).各浓度组在PM2.5环境中分别暴露12 h、24 h、48 h后,以暴露24 h后各浓度组间差异较12h、48 h明显,确定24h为最佳的干预时间.经不同浓度的PM2.5干预24 h后,H1组较H0组、H5组较H4组的细胞早期凋亡率无明显增加,差异无统计学意义(P＞0.05),余各组与H0组比较,细胞早期凋亡率明显增加,差异有统计学意义(P＜0.05).干预24 h后,各浓度组的细胞总凋亡率较H0组均增加明显,且随干预浓度的增加,细胞凋亡率相应增加,组间差异有统计学意义(P ＜0.05).不同浓度PM2.5干预24 h后,H1组较H0组、H4组较H3组的GRP78 mRNA的相对表达量无明显增加,差异无统计学意义(P＞0.05),余各组与H0组比较,GRP78 mRNA的相对表达量均增加,组间差异有统计学意义(P＜0.05).干预24 h后,各浓度组的细胞CHOP mRNA的相对表达量较H0组增加明显,随干预浓度的增加,其相对表达量相应增加,组间差异有统计学意义(P ＜0.05).结论 PM2.5诱导NR8383细胞凋亡,内质网应激参与PM2.5诱导NR8383细胞凋亡的过程.     

Platelets attenuate production of cytokines and nitric oxide by macrophages in response to bacterial endotoxin

Considerable evidence has been accumulated concerning the roles of platelets in immune responses. In the present study, we examined the functional modulation of macrophages by platelets. When mouse bone marrow-derived macrophages (BMDMs) were co-cultured with platelets, BMDMs produced lower levels of nitric oxide (NO), tumor necrosis factor-α (TNF)-α, and interleukin (IL)-6 in response to a bacterial endotoxin (LPS) and zymosan. The attenuation in the macrophage susceptibility to LPS appeared to be mediated by soluble factors secreted from platelets. The mRNA levels of NOS2 (iNOS), TNF-α, and IL-6 in LPS-stimulated BMDMs that had been cultured with a conditioned medium of platelets were also decreased as analyzed by RT-qPCR. The ability of the platelet-conditioned medium to suppress macrophage NO production was recovered in a high-molecular-weight fraction (>670 kDa) after gel-filtration chromatography on a Superose 6 column. These results suggest that platelets control the susceptibility of macrophages to prevent excessive responses to LPS and provide mechanistic insight into a previous report that experimental thrombocytopenia aggravated organ failure in LPS-induced endotoxemia.     

Recombinant SSP4 protein from Trypanosoma cruzi amastigotes regulates nitric oxide production by macrophages

Acute infection with Trypanosoma cruzi is characterized by immunosuppression mediated by T cells and macrophages (Mphis). Nitric oxide (NO) production during the initial phase of acute infection might participate in the clearance of parasites by Mphis, whereas its overproduction during the late phase of acute infection would account for the immunosuppression observed. Trypanosoma cruzi molecules that might regulate the host responses have not been fully identified. Here, we demonstrate that active immunization with MBP::SSP4, a recombinant protein derived from a surface antigen specific of T. cruzi amastigotes (TcSSP4), was able to stimulate Ab production (IgG1, IgG2a, and IgG2b). On the other hand, MBP::SSP4 was able to stimulate NO production by peritoneal Mphis from BALB/c mice and Mphis from the J774 cell line. This effect was also observed at the level of inducible nitric oxide synthase (iNOS) detected by Western Blot. Furthermore, MBP::SSP4 was also shown to induce the expression of IL-1alpha, IL-6, IL-12, IFN-gamma, and TNF-alpha in normal animals, and IL-10 in immunized animals. In addition the protein MBP::SSP4 was able to bind to the surface of PMphis and J774 Mphis. These results suggest that TcSSP4 could modulate Mphi NO production and this may represent a mechanism participating in the immunoregulatory processes during Chagas' disease.     

Nitric oxide production in PCD: possible evidence for differential nitric oxide synthase function

Primary cilliary dyskinesia (PCD) is characterized by decreased levels of fractional exhaled nitric oxide (FeNO), thought to reflect low activity of airway inducible nitric oxide synthase (iNOS) levels. Alveolar NO (Calv) concentration and bronchial NO (JNO) flux can be calculated from FeNO measured at multiple exhalation flow rates. We hypothesised that whereas bronchial NO would be reduced in PCD due to reduced iNOS function, alveolar NO would reflect endothelial NOS (eNOS) function and be normal. We recorded the medical history; measured FeNO at multiple flow rates (50, 100, 200, 260 ml/sec); and performed spirometry in 24 children (aged 8-16 years). FeNO50 of the PCD children was significantly lower than normal mean (+/-SD) 8.1 +/- 1.3 ppb versus 12.5 +/- 1.6 ppb, P = 0.033. The mean +/- SD values of PCD (n = 24) and normal (n = 20) subjects were respectively: JNO: 383.5 +/- 307.9 versus 650.1 +/- 489 pl/s, P = 0.033, Calv: 1.60 +/- 0.78 versus 1.60 +/- 0.75 ppb, P = NS. We show that Calv is normal in PCD, demonstrating that there is no generalized disorder of NO handling in this condition. This differs from a previous report. Furthermore, we speculate that these data may provide supportive evidence that variable flow NO measurements can assess the relative activity of iNOS and eNOS.     

西罗莫司联用阿托伐他汀对大鼠血管平滑肌细胞氧化应激损伤和一氧化氮合酶的影响

目的探讨西罗莫司和阿托伐他汀联合使用对大鼠血管平滑肌细胞氧化应激损伤和一氧化氮合酶(NOS)的影响。方法取大鼠血管平滑肌细胞进行实验,分为空白组、DMSO组、西罗莫司组(100nmol/L)、阿托伐他汀组(3μmol/L)和联合组(西罗莫司100nmol/L加阿托伐他汀3μmol/L)。实验各组细胞给予相应药物干预2h后,加入三丁基过氧化氢诱导氧化应激损伤,24h后检测各项指标。结果与空白组比较,DMSO组、西罗莫司组、阿托伐他汀组和联合组细胞增殖率明显下降(P<0.01)。与空白组和DMSO组比较,阿托伐他汀组和联合组超氧化物歧化酶水平明显上升和丙二醛水平明显下降(P<0.05,P<0.01)。与空白组、DMSO组、西罗莫司组比较,阿托伐他汀组和联合组诱导型一氧化氮合酶(iNOS)mRNA和蛋白表达明显下降(P<0.01);联合组iNOS mRNA和蛋白表达较阿托伐他汀组明显下降(P<0.05,P<0.01)。结论在氧化应激状态下,西罗莫司和阿托伐他汀均能抑制大鼠血管平滑肌细胞增殖和抗氧化损伤,维持NOS系统平衡,联合应用的效果优于单独应用。     

Hypouricemia linked to an overproduction of nitric oxide is an early marker of oxidative stress in female subjects with type 1 diabetes

OBJECTIVE: The aim of this study is to verify whether, early in the course of type 1 diabetes and assuming hyperglycemia as the only risk factor, women demonstrate a change in oxidative status due to an interaction between nitric oxide (NO) and uric acid production. METHODS: Thirty-eight women with type 1 diabetes of less than 10 years' duration and with no diabetic complications were compared with 25 matched healthy female controls. Insulin, C-peptide, NO, HbA(1c) and oxidative stress metabolites were determined from venous blood samples taken from all patients after a 12 h overnight fast. Urine samples were used for urinary uric acid determination. RESULTS: Most oxidative stress metabolites were significantly increased (p < 0.0001), while plasmatic and urinary uric acid levels were significantly lower (p < 0.0001) in patients with type 1 diabetes compared with controls. Mean NO levels were inversely related to uricemia. Bivariate regression analysis showed a significant correlation between plasmatic uric acid and NO (p = 0.004), ascorbic acid (p = 0.042), triglycerides (p = 0.014) and HbA(1c) (p < 0.0001). Linear multivariate regression analysis showed a significant relationship between HbA(1c) and plasmatic uric acid (beta = - 0.465, p = 0.0004). CONCLUSIONS: Oxidative stress is already present in the early stages of type 1 diabetes. We conclude that the initial increase in oxidative stress could be linked to a reduction in plasmatic levels of uric acid, which is probably directly caused by an overproduction of NO.     

促红细胞生成素对新生大鼠心脏成纤维细胞氧化应激时一氧化氮合酶系统的影响

目的:探讨促红细胞生成素(EPO)对心脏成纤维细胞(CFs)氧化应激时一氧化氮合酶(NOS)系统的影响,以及PI3-K/Akt信号途径在其中的作用。方法:应用胰酶和胶原酶双酶法分离培养新生大鼠CFs,EPO、过氧化氢(H2O2)和PI3-K抑制剂LY294002不同因素干预。化学酶法检测CFs培养液中的NO浓度以及总NOS和其亚型的活性。Western blot检测Akt、p-Akt、eNOS、iNOS蛋白的表达。结果:氧化应激使CFs中iNOS的表达显著上调,活性增强;eNOS蛋白的表达明显下降。同时CFs培养液中NO的合成增加显著,达到(25.94±2.57)μmol/L,是对照组的4倍多(P<0.01)。EPO显著抑制CFs氧化应激时iNOS蛋白的表达,同时上调eNOS蛋白,总的NO浓度也显著下降。Akt磷酸化形式p-Akt的表达水平也明显提高。PI3-K抑制剂LY294002能阻断EPO促进eNOS和p-Akt蛋白表达的作用,但EPO抑制iNOS的作用不能完全被阻断。结论:EPO能促进新生大鼠CFs氧化应激时eNOS蛋白的合成,抑制iNOS蛋白的表达。其促进eNOS的表达是通过激活PI3-K/Akt细胞信号途径来实现,抑制iNOS的机制有待进一步探讨。     

Effect of aging on nitric oxide production by rat alveolar macrophages

Nitric oxide (NO) plays an important role in alveolar macrophages (AM)-mediated defense against infection. The elderly become highly susceptible to respiratory tract infection. Inhibition of NO production significantly suppresses defense against infections. Therefore, it is necessary to elucidate the effect of senescence on NO production of AM. The alveolar microenvironment and lymphocytes affect NO production by AM. We examined whether changes in the alveolar microenvironment, lymphocytes, or AM brought about by aging affect NO production by AM. Bronchoalveolar lavage fluid was used as a substitute for the alveolar microenvironment. The results showed that NO production by AM activated by lymph node cells in bronchoalveolar lavage fluid from old rats in response to concanavalin A decreased compared with that of young rats. AM from aged rats produced less NO than AM from young rats. Bronchoalveolar lavage fluid and lymph node cells from aged rats had no effect on the amount of NO produced by AM. Therefore, age-associated decrease in the functional capacity of AM plays a central role in the decrease of NO production.     

Vascular oxidative stress,nitric oxide and atherosclerosis

In the vascular wall, reactive oxygen species (ROS) are produced by several enzyme systems including NADPH oxidase, xanthine oxidase, uncoupled endothelial nitric oxide synthase (eNOS) and the mitochondrial electron transport chain. On the other hand, the vasculature is protected by antioxidant enzyme systems, including superoxide dismutases, catalase, glutathione peroxidases and paraoxonases, which detoxify ROS. Cardiovascular risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus enhance ROS generation, resulting in oxidative stress. This leads to oxidative modification of lipoproteins and phospholipids, mechanisms that contribute to atherogenesis. In addition, oxidation of tetrahydrobiopterin may cause eNOS uncoupling and thus potentiation of oxidative stress and reduction of eNOS-derived NO, which is a protective principle in the vasculature. This review summarizes the latest advances in the role of ROS-producing enzymes, antioxidative enzymes as well as NO synthases in the initiation and development of atherosclerosis.