丁苯酞对颈动脉狭窄大鼠认知功能及海马CA1区神经元凋亡的影响及相关机制研究

摘要 目的：探讨与研究丁苯酞对颈动脉狭窄大鼠认知功能及海马CA1区神经元凋亡的影响及相关机制。方法：将颈动脉狭窄大鼠大鼠（n=42）随机为三组-模型组、低剂量丁苯酞（20 mg/kg）组和高剂量丁苯酞（40 mg/kg）组,每组14只。低剂量丁苯酞组与高剂量丁苯酞组每天给予20 mg/kg、40 mg/kg丁苯酞灌胃治疗,对照组给予等剂量的生理盐水灌胃,持续21 d。结果：低剂量丁苯酞组与高剂量丁苯酞组治疗第7 d、第14 d、第21 d的BBT评分低于模型组（P<0.05）,高剂量丁苯酞组低于低剂量丁苯酞组（P<0.05）。低剂量丁苯酞组与高剂量丁苯酞组治疗第21 d、第28 d的海马CA1区神经元凋亡指数低于模型组,高剂量丁苯酞组低于低剂量丁苯酞组（P<0.05）。低剂量丁苯酞组与高剂量丁苯酞组治疗第21 d、第28 d的脑组织超氧化物歧化酶（Superoxide dismutase,SOD）活性高于模型组（P<0.05）,丙二醛（Malondialdehyde,MDA）活性低于模型组（P<0.05）,高剂量丁苯酞组与低剂量丁苯酞组对比差异都有统计学意义（P<0.05）。低剂量丁苯酞组与高剂量丁苯酞组治疗第21 d、第28 d的海马CA1区BCL2-Associated X（Bax）、B淋巴细胞瘤-2（B-cell lymphoma-2,bcl-2）蛋白相对表达水平高于模型组（P<0.05）,高剂量丁苯酞组高于低剂量丁苯酞组（P<0.05）。结论：丁苯酞在颈动脉狭窄大鼠的应用能提高海马CA1区Bax、Bcl-2蛋白的表达,抑制神经元的凋亡,改善氧化应激状态,从而提高大鼠的认知功能。     

丁苯酞对脑梗死模型大鼠血清及脑组织突触素及突触后致密物-95表达的影响

摘要 目的：探讨丁苯酞对脑梗死模型大鼠血清及脑组织突触素及突触后致密物（postsynaptic density,PSD）-95表达的影响。方法：将建模成功的大鼠随机平分为三组-丁苯酞组、阿司匹林组与模型组各18只。三组分别给予腹腔注射丁苯酞注射液20 mg/kg+阿司匹林20 mg/kg、阿司匹林20 mg/kg与等体积的生理盐水,1次/d,检测血清及脑组织突触素及PSD-95表达变化情况。结果：（1）治疗第7 d与治疗第14 d后,丁苯酞组和阿司匹林组大鼠改良神经功能评分（Modified neurological severity scores,mNSS）均显著低于模型组（P<0.05）,丁苯酞组低于阿司匹林组（P<0.05）;（2）治疗第7 d与治疗第14 d,丁苯酞组、阿司匹林组大鼠的脑梗死体积百分比均显著低于模型组（P<0.05）,丁苯酞组低于阿司匹林组（P<0.05）;（3）治疗第7 d与治疗第14 d,丁苯酞组、阿司匹林组大鼠血清突触素及PSD-95表达水平均显著高于模型组（P<0.05）,丁苯酞组高于阿司匹林组（P<0.05）;（4）治疗第7 d与治疗第14 d后,丁苯酞组、阿司匹林组大鼠大脑组织突触素及PSD-95蛋白相对表达水平均显著高于模型组（P<0.05）,丁苯酞组高于阿司匹林组（P<0.05）。结论：丁苯酞在脑梗死模型大鼠的应用可促进大鼠血清及脑组织突触素及PSD-95的表达,并减小脑梗死面积,因而有利于大鼠的神经功能的恢复。     

圈养林麝麝香分泌时间节律及影响因素

在2016年和2017年的5—8月,我们对川西马尔康麝场圈养林麝（Moschus berezovskii）的麝香分泌进行了行为与生理监测,对麝香分泌的各阶段进行了准确判定,记录了泌香启动、泌香盛期开始、泌香盛期终止及泌香结束的时间阶段及持续时间长,分析了林麝麝香分泌的时间阶段与体重和年龄等因素的关系。结果表明,马尔康麝场的雄性林麝平均泌香启动日在6月16日[（167.06±7.75）d,n=141],于6月17日进入泌香盛期[（168.52±7.67）d,n=141],6月21日[（172.17±7.26）d, n=138]泌香活动减弱,至6月25日[（176.27±8.11）d, n=131]泌香结束;雄麝体重与其泌香启动、泌香盛期停止及泌香结束时间呈显著负相关（r_PS = -0.234,P_PS =0.028;r _VSF = -0.215,P_VSF = 0.047;r _SE = -0.229,P_SE = 0.043）,即雄麝的体重越大,其泌香越早;各年龄组间的平均泌香时长差异显著（F _{17, 113} = 3.482, P = 0.003）,其中2岁雄麝平均泌香时长最长[（13.07±2.08）d, n=20],显著高于3岁[（9.38±0.76）d, n=12, P = 0.042]和4岁[（7.80±1.60）d, n=5, P = 0.013]个体;马尔康林麝平均泌香量为（11.85g±0.96）g, （n=114）,随泌香时长延长有增加趋势,但不显著（P = 0.854）。基于上述林麝雄体的泌香时间、泌香量与年龄和体重等因素间的关联,可对圈养的林麝个体间的泌香力、泌香量等进行区分和预判,作为圈养林麝驯养生产力优化的依据,并可为圈养林麝优质品系的选育提供参考。     

MAPK信号通路对大鼠低氧性PASMCs增殖、凋亡的调控

目的：研究低氧性大鼠肺动脉平滑肌细胞（PASMC）的增殖、凋亡与丝裂原活化蛋白激酶（MAPK）关系。方法：用组织酶消化法获取肺动脉平滑肌细胞（PASMCs）,进行原代培养;采用普通光学显微镜和免疫荧光染色法,分别鉴定PASMCs;选择处于对数生长期的4~6代PASMCs,随机分为7组进行造模：常氧对照组（N）、低氧组（H）、DM-SO组（D）、U0126组（U）、SB203580组（S）、Anisomycin组（A）、Staurosporine Aglycone组（SA）;N组加入10%培养基后置于常氧培养箱中,其它各组分别加入含相应药物的10%培养基后置于低氧培养箱（3% O₂,5% CO₂,37℃）中,造模时间均为48 h。CCK-8法检测各组PASMCs增殖情况;TUNEL法测定各组PASMCs凋亡情况。结果：与N组相比,H组PASMCs的OD值显著上调（0.990 ±0.041 vs 1.143 ±0.033,P < 0.01）,凋亡指数没有明显变化（4.913 ±0.451 vs 5.452 ±0.557,P > 0.05）;与H组相比,D组PASMCs的OD值和凋亡指数均无显著变化（1.143 ±0.033 vs 1.142 ±0.049,5.452 ±0.557 vs 5.402 ±0.651,均P > 0.05）;U组PASMCs的OD值下降,凋亡指数升高（1.143 ±0.033 vs 0.985 ±0.078,5.452 ±0.557 vs 10.145 ±2.545,均P < 0.01）;S组PASMCs OD值上调,凋亡指数明显下调（1.143 ±0.033 vs 1.295 ±0.039,5.452 ±0.557 vs 3.093 ±0.409,均P < 0.01）;A组PASMCs的OD值下降,凋亡指数升高（1.143 ±0.033 vs 0.347 ±0.067,5.452 ±0.557 vs 25.753 ±1.262,均P < 0.01）;SA组PASMCs OD值上调,凋亡指数下调（1.143 ±0.033 vs 1.685 ±0.100,5.452 ±0.557 vs 1.700 ±0.095,均P < 0.01）。结论：低氧对PASMCs增殖和凋亡的调控与MAPK信号通路有关。     

口服活性AdipoRon对2型糖尿病小鼠肝脏氧化应激的干预作用

目的：研究口服活性AdipoRon对2型糖尿病小鼠肝脏氧化应激是否有干预作用,为临床应用提供基础资料。方法：将健康雄性C57BL/6小鼠分为正常组（n=8）,糖尿病组（n=8）,AdipoRon高剂量治疗组（n=8）,Adi-poRon低剂量治疗组（n=8）,以高脂饲料喂养6周后腹腔注射40 mg/kg链脲佐菌素（STZ）诱导2型糖尿病模型,用高、低剂量的口服活性AdipoRon分别对治疗组灌胃治疗10 d后,检测相关生化指标,Western-blot法检测肝脏组织中IRS-1蛋白的表达;实时荧光定量PCR检测胰腺组织中PDX-1 mRNA的表达。结果：DM组小鼠血糖值明显高于NC组（P < 0.05）,DM+L组和DM+H组小鼠血糖值显著低于DM组。DM组小鼠肝脏组织中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性显著低于NC组（P < 0.05）,丙二醛（MDA）及一氧化氮合酶（NOS）活性显著高于NC组（P <0.05）;DM+L组和DM+H组SOD、CAT活性明显高于DM组（P < 0.05）,MDA及NOS活性显著低于DM组（P <0.05）。肝脏组织中IRS-1的蛋白表达及胰腺PDX-1 mRNA表达显著升高,存在统计学意义（P < 0.05）。结论：口服活性AdipoRon对糖尿病小鼠肝脏组织氧化应激有一定的干预作用,能降低小鼠的血糖水平。     

苦参碱对大鼠乳腺癌细胞荷瘤生长及其炎性因子与免疫功能的影响

目的：探讨苦参碱对大鼠乳腺癌细胞荷瘤大鼠生长及其炎性因子与免疫功能的影响。方法：雌性Wistar大鼠60只,随机分为对照组（n=10）,乳腺癌细胞荷瘤大鼠建模组（n=50）。建模大鼠再随机分为5组（n=10）：模型组、苦参碱低（50 mg/kg）、中（100 mg/kg）、高（200 mg/kg）剂量组和香菇多糖（200 mg/kg）组。除对照组外,每只大鼠右腋皮下接种0.4 ml Walker 256乳腺癌细胞悬液（5×10⁷ cells/ml）。按10 ml/kg的体积腹腔注射给药,2次/日,连续14 d。14 d后麻醉大鼠,腹主动脉取血,取瘤组织称取质量,计算抑瘤率;检测大鼠外周血IL-2、IFN-γ、IL-6、IL-10、TGF-β、CD3⁺、CD4⁺、CD8⁺、IgG、IgM、IgA水平。结果：苦参碱低、中、高剂量组和香菇多糖组大鼠瘤块平均质量分别为（4.99±0.93）g、（4.52±0.92）g、（4.22±1.18）g、（4.52±0.92）g,与模型组（6.62±1.20）g比较均明显降低（P<0.01）。苦参碱各剂量组与香菇多糖组比较,瘤块平均质量无明显差异（P>0.05）。苦参碱低、中、高剂量组和香菇多糖组抑瘤率分别为24.6%、31.7%、36.3%和27.9%,组间无统计学差异。模型组大鼠IL-2、IFN-γ、CD8⁺较对照组明显降低（P<0.01）;而IL-6、IL-10、TGF-β、CD3⁺、CD4⁺、IgG、IgM、IgA较对照组明显升高（P<0.01）。苦参碱低、中、高剂量组和香菇多糖组IL-2、IFN-γ、CD8+较模型组显著升高（P<0.01,P<0.05）;而IL-6、IL-10、TGF-β、CD3⁺、CD4⁺、IgG、IgM、IgA较模型组明显降低（P<0.01,P<0.05）。与香菇多糖组比较,苦参碱低、中剂量组IgM、IgA明显升高（P<0.01,P<0.05）;高剂量组IL-2和IFN-γ、IgA水平明显升高（P<0.01,P<0.05）;低剂量组IFN-γ水平明显降低（P<0.05）;高剂量组IL-10、CD4⁺水平明显降低（P<0.01,P<0.05）。结论：苦参碱具有明显的抑制肿瘤生长的作用,其抑瘤机制与其提高细胞和体液免疫、减轻炎症反应有关。     

预热处理对离心运动大鼠骨骼肌超微结构、血清CK、LDH及氧化应激的影响

目的：采用离心运动和热处理研究预热处理对离心运动大鼠骨骼肌的保护作用。方法：SD大鼠分安静组（n=8）,运动组（n=32）和预热处理运动组（n=40）,运动组运动完成后分为运动即刻组（E1）、运动后24 h组（E2）、运动后48 h组（E3）和运动后6 d（E4）组,热处理组在4个周期热处理后分热处理安静组（HE）、热处理运动即刻组（HE1）、热处理运动后24 h组（HE2）、热处理运动后48 h组（HE3）和热处理运动后6 d（HE4）组;运动采用-16°坡度、速度20 m/min、时间120 min的一次性离心力竭跑台运动至力竭模型;预热处理采用每4 d为一个周期,3 d进行热处理、1 d休息,共4个周期,期间湿度控制在50%,肛温起始温度从39 ±0.5℃,依次递增到39.5 ±0.5℃、40.5 ±0.5℃和41.5 ±0.5℃,监测大鼠直肠温度达到预定值以后维持15 min。实验后取血和骨骼肌,观察骨骼肌超微结构和血清肌酸激酶（CK）、乳酸脱氢酶（LDH）及氧化应激指标的变化。结果：预热处理运动后不同时相血清CK、LDH值低于单纯运动组,其中HE1及HE2组与同时相的E1、E2的CK值都呈显著性差异（P < 0.05）,HE1、HE2及HE3组的血清LDH值显著低于同时相的E1、E2及E3组（P < 0.05）;HE2及HE3组的血清超氧化物歧化酶（SOD）值都分别高于同时相的E1、E2组,并且两两之间呈显著性差异（P < 0.05）,HE2组的血清丙二醛（MDA）值显著低于E2组（P < 0.05）。结论：运动预热处理对预防运动性骨骼肌损伤有一定作用。     

牛磺酸镁抗豚鼠尖端扭转型室速的作用研究

目的：研究牛磺酸镁配位化合物（TMCC）抗豚鼠心脏尖端扭转型室速（TdP）的作用。方法：取健康、体重250~300 g的成年雄性豚鼠,随机分为4组：① TdP模型组（n=7）：离体心脏以K-H灌流液灌流20 min,然后使用IKs阻滞剂10μmol/L Chromanol 293B合并低钾（钾离子浓度为1.8 mmol/L）进行灌流,建立TdP模型。②~④ TdP模型+TMCC低中高浓度组（n=6）：正常灌流稳定20 min后,在建立TdP模型的同时分别给予1、2、4 mmol/L TMCC。采用Langendorff逆行主动脉灌流法灌流豚鼠离体心脏,利用Biopac电生理记录仪采集并记录豚鼠离体心脏表面心电图。从心电图第Ⅱ导联图形获取各组豚鼠离体心脏TdP发生率、跨室壁复极离散度、QT间期不稳定性,以观察TMCC对TdP的影响。观测指标量取时间分别为：豚鼠离体心脏正常灌流20 min时、TdP发生前及给药60 min时。结果：TdP模型组的TdP发生率为6/7。1、2、4mmol/L TMCC可降低TdP发生率,三组TdP发生率分别为5/6、1/6、0/6。与给药前相比,TdP模型组中Chromanol 293 B合并低钾可使豚鼠离体心脏校正后的跨室壁复极离散度显著增大（P<0.01）;与TdP模型组相比,TdP模型+1、2、4mmol/L TMCC组可明显减弱Chromanol 293B合并低钾导致的豚鼠离体心脏校正后的跨室壁复极离散度增大（P>0.05）。与模型组相比,2、4mmol/L TMCC明显降低Chromanol 293B合并低钾导致的QT间期不稳定增大（P<0.05）。在TdP模型建立过程中,从心电图中可观察到连续多个心动周期的P波消失,而在TdP模型+TMCC组中,心电图始终拥有独立P波。结论：TMCC可通过降低离体心脏跨室壁复极离散度和QT间期不稳定性以及抑制早后除极的发生而发挥抗TdP作用,降低TdP发生率。     

血浆miRNA-1、miRNA-21对冠心病合并糖尿病患者PCI术后支架内再狭窄的影响

目的：观察血浆miRNA-1、miRNA-21在冠心病（CHD）与无冠脉病变患者中含量的差异,探讨其在CHD合并糖尿病（DM）患者的经皮冠状动脉介入治疗（PCI）后发生支架内再狭窄（ISR）与非支架内再狭窄（NISR）患者的含量差异及其对ISR的预测价值。方法：入选CHD支架置入术后患者（CHD组,n=187）、无冠脉病变患者（对照组,n=195）。根据指南,将对照组分为正常对照组（n=150）、单纯DM组（n=45）;将CHD组分为单纯CHD组（n=119）、CHD合并DM组（n=68）,又将CHD组分为ISR组（n=48）及NISR组（n=139）;再将ISR组分为单纯ISR组（n=26）和ISR合并DM组（n=22）。收集各组患者血浆,提取总miRNA,检测miRNA-1、miRNA-21含量并分析各组的含量差异。结果：与对照组比较,CHD组miRNA-1、miRNA-21含量均升高（P<0.05）;与NISR组比较,ISR组miRNA-1、miRNA-21含量均升高（P<0.05）。与单纯CHD组比较,CHD合并DM组ISR发生率明显升高;而且与单纯ISR组比较,ISR合并DM组miRNA-21含量升高（P<0.05）,而单纯ISR组与ISR合并DM组miRNA-1含量无明显差异（P<0.05）。Logistics分析表明,与CHD患者相关危险因素DM、miRNA-1、miRNA-21的OR值分别为2.132,3.066,1.924（P<0.05,P<0.01）;ISR患者相关危险因素DM、miRNA-21的OR值分别为3.091,5.654（P<0.05,P<0.01）;CHD合并DM患者PCI术后发生ISR相关危险因素miRNA-21的OR值为9.148（P<0.01）。ROC曲线评价表明,miRNA-1,miRNA-21与CHD患者发生ISR的AUC分别为0.854,0.857;miRNA 21与CHD合并DM患者发生ISR的AUC为0.783。结论：血浆miRNA-1、miRNA-21对诊断CHD患者支架置入术后ISR发生有重要临床意义,miRNA-21对诊断CHD合并DM患者支架置入术后ISR发生尤其有重要临床意义。     

Zmu-1：DHP和DHP两个品系豚鼠组胺激发试验气道反应性的比较

目的研究Zmu-1：DHP和DHP豚鼠组胺激发试验气道反应性的差异,为哮喘研究提供具有较好反应性的动物模型。方法通过活体气管插管及雾化组胺气体吸入,测定豚鼠气道阻力和肺动态顺应性;采用离体气管片组胺滴定法,通过气管片收缩测定气管平滑肌对组胺的敏感性;采用同位素标记药物配位法,测定豚鼠气道组织组胺H1受体的密度及平衡解离常数。结果当豚鼠吸人大于0．5mg／mL雾化组胺时,Zmu-1：DHP豚鼠气道阻力上升率和肺动态顺应性下降率与DHP豚鼠相比,其速度有增大趋势,但未达到显著水平（P〉0．05）;两个品系豚鼠雄性个体比雌性的敏感性显著增加（P〈0．01）。当组胺浓度为10-5mol／L和10μmol／L时,Zmu-1：DHP豚鼠气管片平滑肌的收缩率显著大于DHP豚鼠（P〈0．01～0．05）。两个品系豚鼠气道组胺Hl受体的密度及其平衡解离常数无显著差异（P〉0．05）。结论在一定的组胺浓度范围内,Zmu-1：DHP豚鼠气道平滑肌对组胺的敏感性大于DHP豚鼠,雄性豚鼠的敏感性大于雌性豚鼠。两个品系豚鼠气道组胺H1受体数量无差异,提示气道反应可能还受到平滑肌膜上其它受体和化学介质的作用。     

Effects of butylphthalide on bronchial asthma in guinea pigs and involvement of endothelin

Objective: To study the effects of butylphthalide on bronchial asthma in guinea pigs, and investigate the involvement of endothelin. Methods: In guinea pigs, bronchial asthma was induced by injection of ovalbumin(OVA) and provoked by inhalation of OVA, and the effects of butylphthalide on asthma were evaluated through the changes it induced by OVA, pulmonary function, endothelin-1(ET-1) contents and activity of endothelin converting enzyme-1(ECE-1) in bronchoalveolar lavage fluid(BALF), serum and lung tissue, and the gene expression of ET-1 in lung tissue. Results: Butylphthalide significantly improved pulmonary function, lowered asthmatic behavior score, inhibited the activity of ECE-1, and reduced ET-1 gene expression level in lung tissue. Conclusion: Butylphthalide has an anti-asthma effect and the mechanisms involve inhibition of ECE-1 activity and lowering of ET-1geng expression.     

哮喘豚鼠肺内ADM表达变化及对离体气管条张力的作用

目的：通过观察肾上腺髓质素（ADM）mRNA在豚鼠哮喘模型肺内的表达及对哮喘豚鼠离体气管条张力的影响,研究ADM在支气管哮喘（简称哮喘）发病机制中的作用。方法：用原位杂交方法检测ADM mRNA在豚鼠哮喘模型肺内的表达,用组胺诱导豚鼠离体气管条收缩后,观察不同浓度的ADM对其收缩作用影响。结果：原位杂交结果显示正常及哮喘豚鼠肺内均有ADM mRNA的表达,但哮喘组较正常组明显增多（P＜0．05）,ADM可抑制组胺诱导的哮喘豚鼠离体气管条的收缩,并呈量效关系,当浓度达10^-8mol/L时抑经达到最大,而且即使加大ADM的浓度,抑制率未继续明显增加,并对致敏气管螺旋条的舒张作用明显大于正常气管螺旋条。结论：哮喘时,肺内ADM mRNA的表达明显增多,ADM可抑制组胺诱导的豚鼠离体气管条的收缩,浓度为10^-8mol/L时抑制率达到最大。提示ADM在哮喘发病过程中起重要作用。     

The effect of ONO-3708, a novel TxA2 receptor antagonist, on U-46619-induced contraction of guinea pig and human tracheal strips in vitro and on bronchoconstriction in guinea pigs in vivo.

The effect of (9, 11), (11, 12)-didedoxa-9 alpha, 11-alpha-dimethylmethano-11,12-methano-13,14-dihydro-13-aza-14-oxo -15-cyclo-pentyl-16, 17, 18, 19, 20-pentanor-15-epi-TxA2 (ONO-3708) on 9,11-methanoepoxy-prostaglandin H2 (U-46619)-induced contraction of airway smooth muscle in the guinea pigs and human in vitro and bronchoconstriction in guinea pigs in vivo was investigated. In in vitro experiments, ONO-3708 inhibited the U-46619-induced contraction of isolated guinea pig and human tracheal smooth muscle in a dose related fashion (guinea pig; pA2=7.78, human; pA2 = 7.43). The contractions of guinea pig tracheal muscle caused by histamine and leukotriene D4 (LTD4) were not inhibited by ONO-3708. In in vivo experiments, intravenous injection of ONO-3708 at doses between 1 and 20 mg/kg inhibited the U-46619-induced increase of airway insufflation pressure as measured by Konzett-R?ssler method. In addition, ONO-3708 inhibited the U-46619-induced increase in airway reactivity to acetylcholine. These data suggest that ONO-3708 has possible therapeutic utility for asthma in which TxA2 participates.     

豚鼠气管平滑肌化学介质敏感性与体征表型的相关性

目的研究豚鼠体征表型与气管平滑肌化学介质敏感性的相关性。方法根据体征表型眼睛颜色、毛色、性别差异选取36只豚鼠,将动物按体征表型分为白色黑眼雌性组（WBEF）,白色黑眼雄性组（WBEM）,白色红眼雌性组（WREF）,白色红眼雄性组（WREM）,杂色黑眼雌性组（VBEF）,杂色黑眼雄性组（VBEM）,每组动物各6只。用旋割法制备离体豚鼠气管螺旋条,以组胺histamine（浴槽浓度2.0×10^-3g/L）和乙酰胆碱acetylcholine（浴槽浓度2.0×10^-4g/L）诱导气管螺旋条收缩,用BL420生物信号采集系统与张力传感器测定标本张力变化值,分析豚鼠眼睛颜色、毛色、性别与组胺、乙酰胆碱诱导的气管螺旋条收缩效应强弱的关系。数据采用SPSS 11.5软件在α=0.05的信度下进行单因素方差检验。结果豚鼠毛色与眼睛颜色表型其气管平滑肌化学介质敏感性差异有显著性（P〈0.05）,白色体征表型豚鼠的气管平滑肌化学介质敏感性较杂色表型高,红色眼睛表型较黑色眼睛表型高。性别表型对其介质敏感性差异不显著。结论毛色、眼睛颜色表型不同其豚鼠气管平滑肌化学介质敏感性差异显著,性别表型不同其介质敏感性差异不显著,平喘动物模型宜优先选择白色红眼表型豚鼠。     

Protease-activated receptor 2 in regulation of bronchomotor tone: effect of tobacco smoking

Protease-activated receptors are G protein-coupled receptors activated by serine-proteases. Protease-activated receptor 2 is involved in the regulation of airway smooth muscle tone but its effects vary according to species and experimental conditions. We determined the effects of protease-activated receptor 2 activation on smooth muscle tone and airway reactivity to histamine in guinea pigs and smoking or non-smoking humans. The effects of trypsin and protease-activated receptor activating peptide on the isometric tension and response to histamine of guinea pig tracheal and human bronchial rings were studied. Human tissues were obtained from 6 smokers and 4 non-smokers. We assessed the effects of epithelial removal, inhibitors of cyclooxygenases, nitric oxide synthases, neutral endopeptidase and antagonists of acetylcholine, histamine, bradykinin and tachykinin receptors. Bronchomotor responses to protease-activated receptor 2 activation were variable in guinea pig, in half of animals PAR2 activation induced smooth muscle relaxation through the epithelial release of prostanoids but not of nitric oxide. In human airways, protease-activated receptor 2 activation reduced responsiveness to histamine in bronchial rings from smokers but increased responsiveness in bronchi from non-smokers. This study demonstrates an influence of tobacco smoking on the effect of protease-activated receptor 2 activation on airway responsiveness in humans, with an increased protection against histamine-induced contractions, probably through an increased epithelial release of prostanoids. The role of airway protease-activated receptor 2 may be to maintain smooth muscle tone homeostasis.     

Antigen-induced elevation of immunoreactive endothelin-1 (ET-1) levels in ovalbumin-sensitized guinea pig airway tissue

Changes in the immunoreactive ET-1 levels during the anaphylactic reaction of airway tissue from ovalbumin-sensitized guinea pigs were investigated. ET-1-immunoreactivity (ET-IR) was detected in the epithelial and smooth muscle layers of tracheal sections from normal guinea pigs and it was enhanced slightly by phosphoramidon (1 μM) treatment. The ET-IR level of the epithelial layer of ovalbumin-treated tissue from actively sensitized animals was slightly higher than that from normal animals, but it was enhanced markedly by phosphoramidon (1 μM) treatment. Furthermore, the mean ET-IR level of homogenates of antigen-treated tracheal tissues from sensitized guinea pigs (22.8±1.55 fmol mg⁻¹ protein, n=5) was significantly higher than the corresponding normal level (12.3±1.21 fmol mg⁻¹ protein, n=5). These results suggest that increased epithelial airway ET-1 levels contribute to the anaphylactic reaction of guinea pig airways.     

Glutamate receptors and the airways hyperreactivity

It is proposed the link between the hyperactivity of NMDA receptors and airway hyperresponsiveness. We investigated the effect of agents modulating the activity of NMDA receptors in the ovalbumin-induced airway hyperreactivity in guinea pigs. The airways hyperreactivity was influenced by the agonist (NMDA) and selective antagonist - competitive (AP-5) and non-competitive (MK-801) of NMDA receptors. Airway responsiveness to histamine or acetylcholine was evaluated in in vitro conditions. NMDA administration caused the increase of tracheal smooth muscle response in ovalbumin-induced hyperreactivity to acetylcholine. MK 801 as well as AP-5 provoked the decrease of reactivity mainly to acetylcholine in tracheal smooth muscle, while the former, non-competitive antagonist was more effective. We recorded more pronounced response in tracheal than in lung tissue smooth muscle with more considerable response to acetylcholine than to histamine. The results of experiments show the modification of airway smooth muscles responses by agents modulating the activity of NMDA receptors. They confirm the possibility of NMDA receptors participation in experimental airway hyperreactivity. The results enlarge information regarding the link of the inflammatory diseases and glutamatergic system.     

Functional role of nitric oxide in guinea pig tracheal epithelium

Nitric oxide (NO) may play an important regulatory role in airway function. We have, thus, investigated in vitro whether epithelium derived NO may modulate cholinergic neurotrasmission, via release of NO in guinea pig trachea, by using L-arginine (L-ARG), a precursor of NO synthesis, and L-N^G-nitro-arginine-methyl-ester (L-NAME), an inhibitor of NO synthase. Results show that L-ARG and L-NAME modify acetylcholine sensitivity in epithelium-intact smooth muscle preparations, suggesting a probable NO synthesis by tracheal guinea pig epithelium.     

Epithelial modulation of allergen and drug effects in guinea pig airways.

The effect of egg albumin (EA) challenge on tracheal tube preparations from sensitized guinea pigs was studied with regard to EA permeability, histamine release and penetrability, and the contractile response of the preparation. We used a plethysmographic method that allowed simultaneous measurement of changes in smooth muscle tension and collection of samples for determination of mediators. Our results clearly show that epithelial damage potentiates the contractile response to histamine, potassium ions, and acetylcholine. Epithelial damage did not alter the maximal contractile response in preparations challenged with high antigen concentrations (EA, 1 mg/ml), but histamine release measured in the perfusate increased substantially. The permeability of the preparations to EA was greater when the epithelium was damaged. No increase in the permeability in response to the EA challenge was observed. The present study has demonstrated that guinea pig airway epithelium constitutes a barrier for both antigen and drugs. We also present a method for recording contractile responses from intact whole tracheal preparations, in which the epithelium can still act as a barrier, as is the case in vivo.     

Activation of endogenous GABAA channels on airway smooth muscle potentiates isoproterenol-mediated relaxation

Reactive airway disease predisposes patients to episodes of acute smooth muscle mediated bronchoconstriction. We have for the first time recently demonstrated the expression and function of endogenous ionotropic GABA(A) channels on airway smooth muscle cells. We questioned whether endogenous GABA(A) channels on airway smooth muscle could augment beta-agonist-mediated relaxation. Guinea pig tracheal rings or human bronchial airway smooth muscles were equilibrated in organ baths with continuous digital tension recordings. After pretreatment with or without the selective GABA(A) antagonist gabazine (100 muM), airway muscle was contracted with acetylcholine or beta-ala neurokinin A, followed by relaxation induced by cumulatively increasing concentrations of isoproterenol (1 nM to 1 muM) in the absence or presence of the selective GABA(A) agonist muscimol (10-100 muM). In separate experiments, guinea pig tracheal rings were pretreated with the large conductance K(Ca) channel blocker iberiotoxin (100 nM) after an EC(50) contraction with acetylcholine but before cumulatively increasing concentrations of isoproterenol (1 nM to 1 uM) in the absence or presence of muscimol (100 uM). GABA(A) activation potentiated the relaxant effects of isoproterenol after an acetylcholine or tachykinin-induced contraction in guinea pig tracheal rings or an acetylcholine-induced contraction in human endobronchial smooth muscle. This muscimol-induced potentiation of relaxation was abolished by gabazine pretreatment but persisted after blockade of the maxi K(Ca) channel. Selective activation of endogenous GABA(A) receptors significantly augments beta-agonist-mediated relaxation of guinea pig and human airway smooth muscle, which may have important therapeutic implications for patients in severe bronchospasm.