GPER-mediated,oestrogen-dependent visceral hypersensitivity in stressed rats is associated with mast cell tryptase and histamine expression

Visceral hypersensitivity (VH) is common in irritable bowel syndrome (IBS), and female patients are more likely to seek healthcare services for IBS-related abdominal pain. Oestrogen has been reported to mediate pain modulation via its receptor, and mast cells are known to participate in the development of visceral hypersensitivity. Our previous studies showed that the G-protein-coupled oestrogen receptor (GPER, also known as GPR30) was expressed by mast cells in human colonic tissues and was associated with IBS type and severity of visceral pain. However, whether GPER is involved in oestrogen-dependent visceral hypersensitivity via mast cell degranulation is still unknown. Rats were subjected to wrap partial restraint stress to induce visceral hypersensitivity and were ovariectomized (OVX) to eliminate the effects of oestrogen on visceral hypersensitivity. OVX rats were treated with oestrogen, an oestrogen receptor α and β antagonist (ICI 182.780), a GPER antagonist (G15) or a GPER agonist (G1), to evaluate the effects of oestrogen via its receptor. The colorectal distention test was performed to assess visceral sensitivity. Immunofluorescence studies were performed to evaluate GPER and mast cell tryptase co-expression. Mast cell number with degranulation was detected by specific staining. Mast cell tryptase expression in rat colon was also investigated by Western blot and immunohistochemistry. Substance P and histamine expression were examined by ELISA. GPER was expressed by the majority of tryptase-positive mast cells in the colonic mucosa. Stressed rats showed increased visceral sensitivity, increased mast cell degranulation, mast cell tryptase expression, and increased colon histamine levels. Ovariectomy reduced stress-induced VH in female rats and decreased mast cell degranulation, mast cell tryptase expression, and histamine levels, whereas oestrogen replacement reversed these effects. In OVX rats, the GPER antagonist G15 counteracted the enhancing effects of oestrogen on stress-induced VH, mast cell degranulation, mast cell tryptase, and histamine expression, whereas VH was preserved after treatment with ICI 182.780. On the other hand, pretreatment with the selective GPER agonist G1 at doses between 1 and 20 μg/kg significantly increased VH, mast cell tryptase, and histamine expression in OVX-stressed rats, mimicking the effects of oestrogen. GPER plays a pivotal role in the regulation of mast cell degranulation, mast cell tryptase expression, and histamine levels and contributes to the development of colonic hypersensitivity in a female rat model of IBS.     

白麻叶和罗布麻叶的化学成分与抗炎活性比较研究

目的 比较研究白麻Apocynum pictum叶和罗布麻Apocynum venetum叶的化学成分及抗炎活性差异。方法 取白麻叶和罗布麻叶,20倍量60%乙醇溶液回流提取 2 次 ,每次 1.5 h ,合并提取液,浓缩、干燥,即得白麻叶提取物（APLE）、罗布麻叶提取物（AVLE）;以每毫升药液0.03 g药材的浓度过HPD300大孔树脂柱,水洗除杂后以60%乙醇溶液洗脱,收集洗脱液,浓缩、干燥,即得白麻叶精制物（APLP）、罗布麻叶精制物（AVLP）。利用UPLC/Q-TOF/MS鉴定白麻叶和罗布麻叶提取物及精制物的化学成分,进而以HPLC检测白麻苷、芦丁、异槲皮苷、金丝桃苷和紫云英苷的含量。在进行急性毒性实验确定最大耐受剂量的基础上,采用小鼠棉球肉芽肿模型考察4种样品对小鼠肉芽肿指数、抑制率和肾上腺指数的影响,并检测血清组胺、5-羟色胺和前列腺素E₂（PGE₂）水平。结果 以UPLC/Q-TOF/MS从4种样品中鉴定出化学成分97个,其中白麻叶和罗布麻叶的共有化学成分82个,主要是黄酮、黄酮糖苷和黄烷酮。HPLC检测结果显示,APLE、APLP中的白麻苷质量分数分别为 2.43%和 11.98%,罗布麻样品中未检出白麻苷,但 AVLP中芦丁、异槲皮苷、金丝桃苷和紫云英苷的质量分数分别是APLP的30.37、1.75、8.64、1.58倍。动物实验表明,与模型组比较,1.50、0.75 g·kg^-1的APLP可显著降低小鼠棉球肉芽肿指数（P＜0.05）,抑制率分别为 25.79%、21.75%;1.50 g·kg^-1剂量可显著降低血清组胺和 5-羟色胺水平（P＜0.05）,0.75 g·kg^-1剂量可显著降低 5-羟色胺水平（P＜0.01）;APLE、APLP 下调 PGE₂水平,差异不显著;AVLE、AVLP 显著升高PGE₂水平（P＜0.05）。结论 白麻叶和罗布麻叶的化学成分同中有异,相同方法制备的样品在抗炎活性上有较为明显的差别,其中APLP的抗炎活性最强,作用机制可能与调节血管活性胺的释放相关。     

氮卓斯汀对哮喘豚鼠炎症细胞粘附功能的影响

目的研究组胺H1 受体拮抗剂氮卓斯汀(Azelastine ,AZT)对哮喘豚鼠炎症细胞粘附功能的影响,探讨氮卓斯汀拮抗哮喘气道炎症的可能机制。方法以卵白蛋白致敏豚鼠制备哮喘模型。采用密度梯度离心法分离并计数支气管肺泡灌洗液(BALF)中嗜酸性粒细胞(EOS)和淋巴细胞(LC)的数量;采用ELISA法检测血浆和BALF中可溶性细胞间粘附分子 1(sICAM 1)和可溶性P选择素(sP S)的含量。通过荧光酶标记法在pharmaciaCAPSystem中测定血清和BALF中嗜酸性粒细胞阳离子蛋白(ECP)的水平。结果氮卓斯汀能显著降低哮喘豚鼠BALF中Eos和LC的数量;在氮卓斯汀治疗组,哮喘豚鼠血浆和BALF中sICAM 1和sP S的含量均显著降低,血清和BALF中ECP的含量也显著降低,与模型组相比均有显著性差异。结论氮卓斯汀能降低哮喘豚鼠sICAM 1、sP S和ECP的水平,抑制Eos和LC的粘附,减少其在气道的浸润。这可能是组胺H1 受体拮抗剂氮卓斯汀拮抗哮喘气道炎症的重要机制之一。     

Histamine receptors in the isolated human middle meningeal artery. A comparison with cerebral and temporal arteries

The subtypes of histamine receptors mediating dilatation of human meningeal arteries have been tested in vitro, using "selective" antagonists, and compared with cerebral and temporal arteries previously examined. Dilatory responses were tested after preconstriction with prostaglandin F2 alpha. Both mepyramine and cimetidine caused a parallel shift to the right of the histamine concentration-response curve, suggesting the presence of both H1- and H2-receptors. Combined treatment with mepyramine and cimetidine caused further displacement of the concentration-response curve to the right. Schild analysis indicated pA2 values of 6.3 for cimetidine and 9.8 for mepyramine in situations of near complete blockade of either of the receptors. Both H1- and H2-receptors seem of importance for the histamine-induced dilatation in meningeal arteries and neither appear to dominate. The data considered in conjunction with our previous findings support the finding that experimental histamine-induced headache due to vasodilatation is intracranial of origin.     

Local cutaneous nerve terminal and mast cell responses to manual acupuncture in acupoint LI4 area of the rats

Previous studies have shown that the effects of manual acupuncture (MA) are contributed by collagen fibers and mast cells in local acupoints, at which acupuncture stimulation causes various afferent fiber groups to be excited. However what happens in local nerve fibers and mast cells after MA remains unclear. The aim of this study was to examine the response of cutaneous nerve fibers and mast cells to MA stimulation in acupoint Hegu (LI4). The contralateral LI4 of the same rat was used as a non-stimulated control. Immnohistochemistry analysis were carried out to observe the expression of histamine (HA), serotonin (5-HT) and nociceptive neuropeptides, calcitonin gene-related peptide (CGRP) and substance P (SP), in the LI4 area. Mast cells were labeled with anti-mast cell tryptase antibody and simultaneously with HA or 5-HT primary antibodies to observe their co-expression. Our results showed that SP and CGRP were expressed more highly on the cutaneous nerve fibers of LI4 after MA stimulation than that of the control. Mast cells aggregated in close proximity to the blood vessels in intra-epidermis and dermis and some of them with degranulation in the lower dermis and subcutaneous tissue of LI4. Both mast cells and their granules appeared with HA (+) and 5-HT (+) expression at stimulated L14 sites, while a few intact mast cells with a little expression of 5-HT and HA were distributed in areas of non-stimulated L14. The results indicated that local cutaneous nerve terminals and mast cells responded to MA with higher expression of SP and CGRP in nerve fibers, as well as with aggregation and degranulation of mast cells with HA and 5-HT granules at acupoint LI4. These neuroactive substances may convey signals to certain pathways that contribute to the effects of acupuncture.     

组胺在缺血再灌注损伤中作用研究进展

组胺作为一种递质,广泛存在于血液及各组织与器官中,在缺血再灌注损伤中起重要作用.组胺在肝脏、脑、心脏、小肠的缺血再灌注中的研究较深入,组胺可通过激活不同受体发挥不同作用,主要通过影响再灌注后炎症因子和氧化应激的水平发挥作用.本文就组胺在缺血再灌注损伤中作用的研究进展作一综述.     

Novel function of histamine signaling in hyperlipidemia‐induced atherosclerosis: Histamine H1 receptors protect and H2 receptors accelerate atherosclerosis

Histamine is not only essential for acute inflammatory reactions, but it also participates in a chronic inflammatory disorder. We generated apolipoprotein E (apoE) and histamine receptors (HHRs), including the major H1 and H2 receptors (HH1R, HH2R) double knockout mice (DKO) to clarify the role of HHRs in hyperlipidemia‐induced atherosclerosis, in which apoE‐KO and DKO mice were fed a high cholesterol diet. We found that pronounced hyperlipidemia‐induced atherosclerotic progression occurred in HH1R/apoE‐DKO mice, but in HH2R/apoE‐DKO mice less atherosclerosis, despite pro‐atherogenic serum cholesterol levels compared with apoE‐KO mice. Furthermore, the increased expressions of scavenger receptors (SRs), such as SR‐A, CD36 and lectin‐like oxidized low‐density lipoprotein receptor 1 (LOX‐1), nuclear factor‐kappa B (NFκB), monocyte chemoattractant protein (MCP‐1), matrix metalloproteinases (MMPs) or liver X receptor (LXR)‐related inflammatory signaling factors, were consistent with the pro‐atherogenic phenotype of HH2R/apoE‐DKO mice. We hypothesize that histamine/HH1R and HH2R signaling has conflicting innate functions, inflammatory/atherogenic and anti‐inflammatory/anti‐atherogenic actions, and that there are innate links between histamine signaling and hyperlipidemia‐induced atherosclerosis, independently of serum cholesterol metabolism. Specific histamine signaling blockers, in particular, HH2R blockers, are a possible novel therapeutic target for hyperlipidemia‐induced atherosclerosis.