益母草对肠易激综合征内脏感觉过敏大鼠肥大细胞和P物质表达的影响

目的探索益母草调节肠易激综合征(IBS)内脏感觉过敏的可能机制。方法采用结肠慢性刺激法制作内脏高敏性的IBS大鼠模型,将实验动物分为正常组、模型组、益母草组,观察益母草对IBS大鼠AWR评分以及结肠肥大细胞(MC)、P物质(SP)含量的影响。结果与对照组比较,模型组大鼠AWR评分,结肠MC、SP含量都明显升高,而益母草组大鼠AWR评分,结肠MC、SP含量与模型组比较明显降低。结论益母草作用机制可能是通过调节MC、SP的分泌,来降低肠道敏感性。     

芍药苷治疗内脏敏感性肠易激综合征的研究

目的:研究芍药苷对内脏敏感性肠易激综合征(IBS)的治疗作用.方法:经肠道连续6天给予冰醋酸或芥末油,分别建立冰醋酸或芥末油大鼠内脏高敏感性IBS模型,灌胃曲美布丁或芍药苷高、中、低剂量药液,每天1次连续3天,观察各组大鼠肠道内扩张引起腹部抬起和背部拱起的容量阈值,记录大鼠结肠电频率、峰电位、峰峰值和面积.结果:曲美布丁及芍药苷中剂量给药后大鼠肠敏感性显著改善,明显降低两种模型大鼠腹部抬起和背部拱起阈值,降低结肠电频率、峰电位、峰峰值及峰面积.结论:芍药苷可通过降低肠道敏感性,改善结肠电生理活动来治疗内脏高敏感性IBS模型大鼠.     

益生菌对肠易激综合征大鼠内脏高敏感性的作用以及肥大细胞-PAR2-TRPV1通路的影响

目的探讨益生菌对肠易激综合征(IBS)大鼠内脏高敏感性的作用以及肥大细胞(MC)-蛋白酶激活受体2(PAR2)-瞬时感受器电位香草酸受体1(TRPV1)轴的影响。方法将30只SD大鼠随机分为空白组、模型组、益生菌组,每组10只。模型组和益生菌组大鼠通过连续6 d醋酸灌肠+束缚应激建立IBS模型。造模成功后,益生菌组大鼠予以双歧杆菌三联活菌胶囊107 CFU/(kg·d)灌胃,1次/d,连用14 d。实验结束时,进行结肠扩张试验(CRD)观察大鼠腹部撤离反射(AWR),检测大鼠粪便含水量及双歧杆菌和大肠埃希菌的比值(B/E值),检测血清5-羟色胺(5-HT)、P物质(SP)、促肾上腺皮质激素释放激素(CRH)水平。甲苯胺蓝染色检测结肠组织MC浸润情况,Western blot法检测脊髓背根神经节(DRG)PAR2和TRPV1蛋白表达量。结果与模型组比较,益生菌组大鼠不同压力扩张情况下AWR评分、粪便含水量、血清5-HT、SP、CRH、IL-12水平、结肠组织MC浸润数量以及DRG组织PAR2和TRPV1蛋白表达量显著降低,而血清IL-10水平和粪便中B/E比值显著升高,差异有统计学意义(P<0.05)。结论益生菌可通过调节肠道菌群紊乱、抑制MC-PAR2-TRPV1轴激活改善IBS大鼠内脏高敏感性,降低炎症反应。     

白术-木香药对对脾虚腹泻型肠易激综合征大鼠肠道菌群与短链脂肪酸代谢的调节作用

目的 探讨白术-木香药对对脾虚腹泻型肠易激综合征（IBS-D）大鼠肠道菌群与短链脂肪酸（SCFAs）代谢的调节作用。方法 使用番泻叶灌胃联合束缚刺激构建大鼠脾虚IBS-D模型。将造模成功的大鼠分为模型组、阳性对照组（匹维溴铵1.5 mg/kg）和白术-木香药对低、中、高剂量组（0.7、1.4、2.8 g/kg）,每组6只;另取6只健康大鼠作为空白对照组。空白对照组与模型组大鼠灌胃生理盐水,其余各组灌胃相应药液,每天1次,连续14 d。观察大鼠一般状况,并检测粪便含水量;检测大鼠肠道敏感性[以腹壁撤退反射（AWR）阈值评价]和肠道推进率;检测大鼠血清中5-羟色胺（5-HT）、P物质（SP）水平;观察大鼠结肠组织病理变化,检测大鼠结肠组织中5-HT3受体（5-HT3R）、5-HT4受体（5-HT4R）、5-HT转运体（SERT）蛋白表达水平。取空白对照组、模型组和白术-木香药对高剂量组大鼠粪便样本进行16S rRNA测序分析,并检测粪便中乙酸、丙酸、丁酸的含量。结果 与模型组比较,白术-木香药对中、高剂量组大鼠给药7、14 d后的体重,粪便含水量,AWR阈值,结肠组织中5-HT4R、SER...     

金荞麦总黄酮下调NR2B表达改善IBS大鼠痛觉过敏

目的观察金荞麦总黄酮(Fag)对IBS样结肠刺激大鼠模型(CI模型)内脏敏感性的改善作用和对模型脊髓后角和海马内NMDA受体亚基NR2A、NR2B的影响。方法采用结肠刺激新生期乳大鼠法来制作IBS样CI模型。CI大鼠成年后给予口服Fag 2周,并用腹壁撤退反射(AWR)评分评价给药后CI大鼠内脏高敏感性的变化,用免疫组化法和蛋白印迹法进一步观察其脊髓后角和海马内NMDA受体亚基NR2A、NR2B的变化。结果和对照组比,CI组AWR评分明显增高,而高剂量Fag明显降低CI组的AWR评分。对照组脊髓后角、海马均可见NR2A、NR2B亚基表达,但CI组只有NR2B亚基表达增强,且高剂量Fag可降低其表达,NR2A亚基表达在各组变化不大。结论 Fag通过下调致敏中枢上脊髓后角和海马的NR2B表达对IBS样CI大鼠的痛觉过敏有改善作用。     

螺环哌嗪盐化合物DXL-A-24对肠易激综合征大鼠内脏高敏感性和肠道菌群的影响

目的:探讨螺环哌嗪盐化合物DXL-A-24对肠易激综合征(irritable bowel syndrome, IBS)大鼠内脏高敏感性和肠道菌群的影响。方法:采用母婴分离联合束缚应激制备IBS大鼠模型，造模成功大鼠随机分为模型组、利那洛肽组(0.022 mg·kg^-1)、螺环哌嗪盐化合物DXL-A-24低、中、高剂量组(2,6,12 mg·kg^-1),每组14只，同时设正常组，连续灌胃28 d。采用腹壁回撤反射评估大鼠内脏敏感性，ELISA法检测结肠组织肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、D-乳酸(D-lactate,D-LA)和二胺氧化酶(diamine oxidase, DAO)含量，免疫组化法检测结肠组织P物质(substance P,SP)和降钙素基因肽(calcitonin gene-related peptide, CGRP)的表达，16S rRNA基因测序分析肠道菌群的变化。结果:与正常组相比，模型组大鼠毛发稀疏发黄，攻击性强，肛周有粪便污染，内脏敏感性明显升高(P<0.05)。与...     

润肠颗粒对小鼠便秘的改善作用及机制

目的 探讨润肠颗粒对小鼠便秘的改善作用及潜在机制。方法 将小鼠随机分为正常对照组、模型组、润肠颗粒低剂量组（5 g/kg）、润肠颗粒高剂量组（10 g/kg）和莫沙必利组（0.003 g/kg,阳性对照）,每组6只。后4组小鼠灌胃洛哌丁胺（0.004 g/kg）,每天2次,持续给药3 d后开始药物治疗,正常对照组和模型组小鼠灌胃纯水,各药物组小鼠灌胃相应药物,连续给药7 d。末次给药后,测定小鼠粪便含水量和肠道推进率,观察结肠和回肠组织结构以及结肠黏液分泌量,检测结肠组织中酪氨酸激酶受体c-kit、黏蛋白2(MUC2)、干细胞因子（SCF）蛋白表达水平以及炎症因子[肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、IL-1β、诱导型一氧化氮合成酶（iNOS）]和促进肠道运动相关因子[神经型一氧化氮合酶（nNOS）、平滑肌肌球蛋白轻链激酶（smMLCK）、5-羟色胺受体4(5-HT4R)、MUC2、SCF、c-kit]mRNA表达水平。结果 与模型组比较,润肠颗粒低、高剂量组和莫沙必利组小鼠粪便含水量,肠道推进率,结肠组织中c-kit蛋白表达水平和MUC2、SCF蛋白相对表达量以及...     

腹泻型肠易激综合征大鼠模型的建立及敏感性评估的实验研究

目的建立腹泻型肠易激综合征(IBS)大鼠模型并对模型的肠道敏感性进行评估。方法将出生8~21d的大鼠乳鼠给予连续性的直肠内炎症性刺激(直肠注入0.087 mol.L-1醋酸0.5 ml),建立IBS内脏感觉过敏的动物模型,通过观察模型大鼠在直结肠扩张时痛觉阈值的变化以及致痉剂对模型大鼠的离体肠管舒缩运动的影响,研究IBS大鼠模型内脏敏感性的变化。结果第6周和第8周模型组抬腹和拱背的压力阈值明显低于正常组(P<0.01),离体肠管运动实验中,加致痉剂后模型组升高比值均大于正常组,差异有显著性(P<0.05)。结论乳鼠的新生期肠道内的慢性炎症刺激,可以在成年后引起慢性内脏敏感性增高,是一个符合IBS基本特征的动物模型。     

c-kit在蒽醌类泻剂所致肠动力减退发病机制中的作用

目的 探讨c-kit在蒽醌类泻剂所致肠动力减退发病机制中的作用.方法 健康成年SPF级SD大鼠36只随机均分为模型组、模型恢复组和对照组.模型组和模型恢复组大鼠采用“大黄酸混悬液灌胃法”制作肠动力减退动物模型,对照组用等体积生理盐水灌胃.模型组造模结束后取材,模型恢复组造模结束正常饲养30 d后取材.各组大鼠处死前观察首粒黑便排出时间以检测肠道传输功能,Western blot法检测各组大鼠结肠组织中c-kit的蛋白水平.结果 模型组和模型恢复组大鼠首粒黑便排出时间较对照组明显延长(P＜0.01)；模型组和模型恢复组结肠组织中的c-kit蛋白表达较对照组明显减弱(P＜0.01).结论 蒽醌类泻剂所致肠动力减退可能与结肠组织中c-kit蛋白表达下调有关.     

鬼针草总黄酮对急性炎症的保护作用及可能机制研究

目的:研究鬼针草总黄酮(TFB)对急性炎症的保护作用与可能机制.方法:二甲苯诱导急性小鼠耳肿胀,检测耳肿胀度和血清TNF-α、IL-1、IL-6、IL-8含量;氟氏完全佐剂诱导佐剂性关节炎(AA)大鼠原发性炎症,检测足肿胀度和血清TNF-α、IL-1、IL-2、IL-6、IL-8含量,HE染色观察炎症关节病理学变化,免疫组织化学法检测关节软骨组织ASIC1a蛋白.结果:小鼠急性耳肿胀和AA大鼠原发性炎症中,模型组动物血清TNF-α、IL-1、IL-6和IL-8含量均明显升高,TFB(100、200mg/kg)灌胃给药能降低小鼠耳肿胀度和血清TNF-α、IL-1、IL-6、IL-8含量,TFB(67、133mg/kg)可以升高AA大鼠血清IL-2的含量.TFB灌胃给药可以使AA大鼠关节炎性细胞减少,改善病理变化.在AA大鼠原发性炎症中模型组大鼠关节软骨组织ASIC1a表达明显升高,TFB(67、133 mg/kg)组ASIC1a的表达明显降低.相关性分析结果显示,AA大鼠原发性炎症中ASIC1a与血清TNF-α、IL-1、IL-8含量呈正相关.结论:TFB对急性炎症具有保护作用,其抗炎机制可能与调节炎症介质释放有关.     

盐酸小檗碱对肠易激综合征大鼠肠上皮紧密连接的影响

目的：观察盐酸小檗碱( Berberine, BER)对肠易激综合征( IBS)大鼠肠上皮紧密连接的影响,探讨其机制。方法将50只SD大鼠随机分为5组,每组10只。除对照组正常进食水外,其他4组采用醋酸灌肠法建立IBS模型,造模成功后予如下方法处理：BER 组予盐酸 BER (100 mg/kg )灌胃;氨基胍组予高度选择性一氧化氮合酶(NOs)阻断剂氨基胍(100 mg/kg)腹腔注射;BER+氨基胍组予BER(100 mg/kg)灌胃,同时氨基胍(100 mg/kg)腹腔注射;生理盐水组予3 ml 生理盐水灌胃。造模后第7天比较5组大鼠腹部回撤反应( abnominal withdrawl reflex, AWR)评分(直结肠扩张试验)、束缚应激试验后排便次数、血浆D-乳酸水平、肠上皮紧密连接( tight junction, TJ)蛋白(Occludin、ZO-1)的表达。结果与对照组比较,BER组、BER+氨基胍组、氨基胍组、生理盐水组4组AWR评分升高,束缚应激后排便增多,D-乳酸水平升高,肠上皮TJ蛋白Occludin、ZO-1表达下降,差异有统计学意义( P<0．05)。BER组AWR评分比生理盐水组明显降低(P<0．05),氨基胍组、BER+氨基胍组AWR评分与生理盐水组比较,差异无统计学意义(P>0．05),BER组AWR评分比BER+氨基胍组明显降低(P<0．05);与生理盐水组比较,BER组和BER+氨基胍组排便次数减少, D-乳酸水平降低,肠上皮蛋白;Occludin、ZO-1表达升高,差异有统计学意义( P <0．05)。排便次数、D-乳酸水平、肠上皮TJ蛋白Occludin与ZO-1表达比较氨基胍组与生理盐水组差异均无统计学意义(P>0．05)。结论 BER影响IBS大鼠肠上皮紧密连接,其机制与一氧化氮有关。     

通腑化瘀汤对术后肠梗阻大鼠肠组织COX-2及Cajal间质细胞表达的影响

目的建立术后肠梗阻大鼠模型,观察通腑化瘀汤对术后肠梗阻大鼠肠组织环氧化酶-2(Cyclooxygenase-2,COX-2)及Cajal间质细胞(Interstitial cells of Cajal,ICC)表达的影响,评估肠粘膜损伤程度,为临床更好地防治术后肠梗阻提供有效的治疗方剂和理论依据。方法取健康雄性SD大鼠45只,随机分为通腑化瘀汤组(药物组)、生理盐水对照组(对照组)、空白组,药物组和对照组给予开腹手术建立术后肠梗阻模型,手术后6、16 h时间点分别给予通腑化瘀汤药液和生理盐水各0.8 m L灌胃,空白组不给予手术处理。处死前取大鼠小肠远端距盲肠约5 cm的肠组织,采用HE染色显微镜下观察肠粘膜损伤情况;免疫组织化学方法检测c-kit蛋白(ICC特异性标志物)和COX-2蛋白的平均光密度值。结果对照组与空白组相比,COX-2表达显著提高(P<0.05),c-kit表达显著降低(P<0.05),肠黏膜损伤程度较重;药物组与对照组相比,COX-2表达显著降低(P<0.05),c-kit表达显著提高(P<0.05),损伤的肠粘膜得到一定程度修复。结论通腑化瘀汤能够减少术后肠梗阻小肠组织COX-2的表达,改善ICC形态并提高ICC数量,抑制炎症反应,对受损伤的肠粘膜起到保护作用。     

Chemical synthesis and folding of APETx2, a potent and selective inhibitor of acid sensing ion channel 3

Acid sensing ion channels (ASICs) are pH-sensitive channels that are distributed in the central and peripheral nervous system and which are believed to play a key role in pain perception. APETx2, a 42-residue peptide toxin isolated from the sea anemone Anthopleura elegantissima, is the only known selective inhibitor of ASIC3 channels. Here we describe the total chemical synthesis of APETx2 by solid-phase peptide synthesis and native chemical ligation. The folded synthetic toxin had an IC₅₀ of 57 nM for inhibition of rat ASIC3 channels expressed in Xenopus oocytes, in agreement with the IC₅₀ reported for the native toxin (63 nM). The native chemical ligation approach should provide an efficient route for synthesis of other pharmacologically useful disulfide-rich toxins from venomous animals.     

Expression in Pichia pastoris and characterization of APETx2, a specific inhibitor of acid sensing ion channel 3

Acid sensing ion channels (ASICs) are family of proteins predominantly present in the central and peripheral nervous system. They are known to play important roles in the pathophysiology of pain and ischemic stroke. APETx2 is a potent and selective inhibitor of ASIC3-containing channels and was isolated from sea anemone Anthopleura elegantissima. To facilitate the study on the molecular determinants of ASIC3-ligand interactions, we expressed recombinant APETx2 in the Pichia pastoris (P. pastoris) expression system and purified it to homogeneity. Recombinant APETx2 produced in P. pastoris inhibited the acid-evoked ASIC3 current with the IC₅₀ value of 37.3 nM. The potency of recombinant toxin is similar to that of native APETx2. The sequential assignment and structure analysis of APETx2 were obtained by 2D and 3D ¹⁵N-edited NMR spectra. Our NMR data suggests that APETx2 produced in P. pastoris retained its native fold. The results presented here provide the first direct evidence that highly disulfide bonded peptide inhibitor of ASIC3, APETx2, can be expressed in P. pastoris with correct fold and high yield. We also showed that the R17A mutant exhibited a decrease in activity, suggesting the feasibility of the use of this expression system to study the interactions between APETx2 and ASIC3. These evidences may serve as the basis for understanding the selectivity and activity of APETx2.     

枳实槟榔散对大鼠肠道高敏感性的影响及其作用机制研究

目的观察枳实槟榔散对大鼠肠道高敏感性的影响及其可能的作用机制。方法采用醋酸慢性刺激乳鼠建立肠道高敏感性大鼠模型,观察枳实槟榔散对大鼠肠道敏感性以及结肠黏膜P物质、5-羟色胺（5-HT）免疫反应阳性纤维的影响。结果枳实槟榔散组的低与高剂量组的痛阈值和最大耐受疼痛阈值与模型组比较有明显升高（P〈0.05）;肠道内P物质含量高于模型组（P〈0.01）,肠道黏膜下的5-HT免疫阳性神经元/神经纤维阳性指数（IOD）显著性减少（P〈0.01）。结论枳实槟榔散可降低大鼠肠道高敏感性,其作用机制可能与引起5-HT免疫阳性神经纤维减少、改善P物质分泌紊乱有关。     

Peptides inhibitors of acid-sensing ion channels.

Acid-sensing ion channels (ASICs) channels are proton-gated cationic channels mainly expressed in central and peripheric nervous system and related to the epithelial amiloride-sensitive Na(+) channels and to the degenerin family of ion channels. ASICs comprise four proteins forming functional channel subunits (ASIC1a, ASIC1b, ASIC2a, and ASIC3) and two proteins (ASIC2b and ASIC4) without yet known activators. Functional channels are activated by external pH variations ranging from pH(0.5) 6.8 to 4.0 and currents are characterized by either rapid kinetics of inactivation (ASIC1a, ASIC1b, ASIC3) or slow kinetics of inactivation (ASIC2a) and sometimes the presence of a plateau phase (ASIC3). ASIC1a and ASIC3, which are expressed in nociceptive neurons, have been implicated in inflammation and knockout mice studies support the role of ASIC3 in various pain processes. ASIC1a seems more related to synaptic plasticity, memory, learning and fear conditioning in the CNS. ASIC2a contributes to hearing in the cochlea, sour taste sensation, and visual transduction in the retina. The pharmacology of ASICs is limited to rather nonselective drugs such as amiloride, nonsteroid anti-inflammatory drugs, and neuropeptides. Recently, two peptides, PcTx1 and APETx2, isolated from a spider and a sea anemone, have been characterized as selective and high-affinity inhibitors for ASIC1a and ASIC3 channels, respectively. PcTx1 inhibits ASIC1a homomers with an affinity of 0.7 nM (IC(50)) without any effect on ASIC1a containing heteromers and thus helped to characterize ASIC1a homomeric channels in peripheric and central neurons. PcTx1 acts as a gating modifier since it shifts the channel from the resting to an inactivated state by increasing its affinity for H(+). APETx2 is less selective since it inhibits several ASIC3-containing channels (IC(50) from 63 nM to 2 microM) and to date its mode of action is unknown. Nevertheless, APETx2 structure is related to other sea anemone peptides, which act as gating modifiers on Nav and Kv channels.     

Inhibition of voltage-gated Na(+) currents in sensory neurones by the sea anemone toxin APETx2

BACKGROUND AND PURPOSE

APETx2, a toxin from the sea anemone Anthropleura elegantissima, inhibits acid-sensing ion channel 3 (ASIC3)-containing homo- and heterotrimeric channels with IC₅₀ values < 100 nM and 0.1–2 µM respectively. ASIC3 channels mediate acute acid-induced and inflammatory pain response and APETx2 has been used as a selective pharmacological tool in animal studies. Toxins from sea anemones also modulate voltage-gated Na⁺ channel (Na_v) function. Here we tested the effects of APETx2 on Na_v function in sensory neurones.

EXPERIMENTAL APPROACH

Effects of APETx2 on Na_v function were studied in rat dorsal root ganglion (DRG) neurones by whole-cell patch clamp.

KEY RESULTS

APETx2 inhibited the tetrodotoxin (TTX)-resistant Na_v 1.8 currents of DRG neurones (IC₅₀, 2.6 µM). TTX-sensitive currents were less inhibited. The inhibition of Na_v 1.8 currents was due to a rightward shift in the voltage dependence of activation and a reduction of the maximal macroscopic conductance. The inhibition of Na_v 1.8 currents by APETx2 was confirmed with cloned channels expressed in Xenopus oocytes. In current-clamp experiments in DRG neurones, the number of action potentials induced by injection of a current ramp was reduced by APETx2.

CONCLUSIONS AND IMPLICATIONS

APETx2 inhibited Na_v 1.8 channels, in addition to ASIC3 channels, at concentrations used in in vivo studies. The limited specificity of this toxin should be taken into account when using APETx2 as a pharmacological tool. Its dual action will be an advantage for the use of APETx2 or its derivatives as analgesic drugs.     

大鼠酸感受离子通道亚基2a表达质粒的构建及生物学特性考察

目的构建大鼠酸感受离子通道亚基2a(acid-sensingion channel subunit 2a,ASIC2a)的表达质粒并研究其组成的同聚体离子通道的生物学特性。方法使用分子生物学技术构建大鼠ASIC2a亚基表达质粒;通过体外转录技术,使编码ASIC2a亚基的cRNA在爪蟾卵母细胞内表达并在膜表面形成同聚体离子通道;使用双电极电压钳技术研究ASIC2a的生物学特性。结果在注射ASIC2a亚基cRNA的爪蟾卵母细胞上,降低胞外液pH值可诱导出内向电流。H+诱发的ASIC2a内向电流具有稳态失活成分可被氨氯吡咪可逆性阻断,其pH50为5.12。提高胞外Ca2+浓度可降低H+诱发的电流幅度,其IC50为11.98 mmol.L-1。当细胞外液中无Na+时,H+基本上不能诱发出内向电流;当同时去除细胞外液中Na+和K+时,H+可诱发出外向电流。结论成功构建ASIC2a表达质粒;ASIC2a除了对Na+通透外,对K+也有一定的通透性,胞外Ca2+抑制ASIC2a孔道的开放。