(+)-儿茶素缓解大鼠低氧性肺动脉高压的作用和机制

研究了(+)-儿茶素对SD大鼠低氧性肺动脉高压(PAH)的影响及其机制。采用27只SD雄性大鼠按随机数字表法分为3组(对照组、缺氧模型组、(+)-儿茶素干预组)。通过检测大鼠平均肺动脉压(Mean pulmonary arterialpressure,mPAP)和肺血管阻力(Pulmonaryvascularresistance,PVR)反应体内肺血流动力学变化;处死大鼠后测算右心室肥厚指数(Rightventriclehypertrophyindex,RVHI)及肺动脉血管壁厚度和外周血管直径的比值(Vascular wall thickness of outer circumference ratio,WT%);WB检测肺动脉内皮细胞一氧化氮合酶(eNOS),用NO试剂盒检测NO表达量;用CCK-8法检测肺动脉平滑肌细胞增殖以确定细胞活力,利用WB检测分析肺动脉平滑肌细胞钙敏感受体(CaSR)、荧光探针法检测细胞内总Ca²⁺的浓度。研究结果表明,与缺氧模型组相比,(+)-儿茶素能够显著减缓肺缺氧诱导的肺动脉压力升高(n=9,P<0.05;);通过逆转缺氧引起的肺内皮细胞一氧化氮合酶(eNOS)显著减少(n=3,P<0.05)和NO合成显著减少(n=5,P<0.05),达到抑制肺动脉内皮血管收缩作用;通过下调缺氧诱导的平滑肌细胞内CaSR表达(n=3,P<0.05),逆转缺氧的升钙效应(n=27,P<0.05),达到抑制平滑肌细胞增殖的作用(n=30,P<0.05)。综上可见,(+)-儿茶素通过抑制肺血管收缩和血管平滑肌细胞增殖来缓解缺氧诱导的PAH,为PAH的治疗方法提供了新思路。     

大豆异黄酮和皂甙对肝癌前病变大鼠血清标志酶及抗氧化活性的影响

采用改良Solt-Faber法建立大鼠肝癌前病变模型,以大豆异黄酮和皂甙饲喂大鼠42 d后,ELISA法测定血清肿瘤坏死因子-α(TNF-α),分光光度法测定γ-谷酰胺转肽酶(γ-GT)、丙氨酸氨基转移酶(ALT)、门冬氨酸氨基转移酶(AST)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-PX)活性及丙二醛(MDA)和一氧化氮(NO)含量。结果表明:大豆异黄酮和皂甙降低肝癌前病变大鼠血清γ-GT、ALT、AST活性,升高血清SOD、CAT、GSH-PX活性和降低MDA以及NO水平,但对血清TNF-α水平没有显著影响。表明大豆异黄酮和皂甙具有明显的抗化学致癌作用,其作用机制可能与增高抗氧化活性有关。     

绿茶降糖作用机制的研究

给糖尿病大鼠口服蔗糖或淀粉和绿茶提取物后,观察糖尿病大鼠糖耐量及血胰岛素的变化,并用比色法测定对α-葡萄糖苷酶（EC 3．2．1,20）和α-淀粉酶（EC 3．2．1．1）的抑制活性,用快速过滤法观察对兔小肠刷状缘囊泡葡萄糖转运活性的影响。结果表明,绿茶提取物能明显改善蔗糖或淀粉负荷糖尿病大鼠的血糖水平。     

人参皂苷Rb3联合二甲双胍对H_2O_2诱导血管内皮细胞损伤的保护作用

目的观察人参皂苷Rb3(G-Rb3)联合二甲双胍对H_2O_2诱导血管内皮细胞损伤的保护作用。方法100μmol/LH_2O_2造成血管内皮细胞氧化应激损伤模型,以cck-8法检测各组细胞增殖情况,测定各组细胞上清液中肿瘤坏死因子-α(TNF-α)、一氧化氮(NO)含量和超氧物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活力。结果 100μmol/LH_2O_2可抑制血管内皮细胞活性,降低NO含量及SOD、GSH-Px活力,升高TNF-α含量。G-Rb3联合二甲双胍能明显抑制过氧化氢损伤引起的细胞活性降低,提高NO含量及SOD、GSH-Px活力,降低TNF-α含量,表明对100μmol/LH_2O_2诱导的血管内皮细胞损伤具有保护作用。结论 G-Rb3可明显增强二甲双胍对血管内皮细胞的保护作用,可能通过调控抗氧化损伤机制实现的。     

白茶提取物对纳米SiO2诱导的大鼠肺纤维化的抑制作用及机制

硅肺是吸入SiO₂粉尘引起的以肺间质纤维化为主的全身性疾病。探讨了白茶提取物对纳米SiO₂诱导大鼠肺纤维化的抑制作用及机制。54只Wistar大鼠随机分为正常组、模型组、白毫银针提取物组、白牡丹提取物高和低剂量组、EGCG组共6个组,每组9只大鼠。除正常组外的其余5个组采用非暴露式气管插管方法造模纳米SiO₂粉尘(80 mg·mL^-1),每天以灌胃方式给予药物两周之后,检测肺组织中羟脯氨酸(HYP)、一氧化氮(NO)、超氧化物歧化酶(SOD)、丙二醛(MDA)和谷光甘肽过氧化物酶(GSH-Px)含量以及肺组织形态学变化。结果显示,与模型组相比,白茶提取物各处理组及EGCG组病理形态改变有不同程度的减轻,其中白毫银针提取物组的效果最佳。白茶提取物各处理组与EGCG组的大鼠肺NO含量和炎症因子IL-6都显著低于模型组(P<0.05),GSH-Px活力高于模型组(P<0.05),高剂量白牡丹提取物对降低NO含量和升高GSH-Px活力效果最好;本研究表明,白茶提取物对于纳米SiO₂引起的大鼠肺纤维化氧化应激损伤具有有效的减缓和修复作用,主要与其抗氧化作用和抑制炎症反应相关。     

组方优化的阳和胶囊对碘乙酸钠诱导大鼠骨关节炎的作用研究

目的探讨组方优化的阳和胶囊对碘乙酸钠诱导的大鼠骨关节炎的治疗作用及其机制研究。方法采用大鼠膝关节腔内注射4%碘乙酸钠溶液0.1 ml,连续注射7天,建立大鼠骨关节炎模型。于造模后分别灌胃给予组方优化的阳和胶囊高、中、低剂量及阳性对照双醋瑞因胶囊(8.0mg/kg),每日1次,连续给药4周。实验期间每周测定大鼠膝关节肿胀度。实验结束后测定大鼠膝关节灌洗液中NO、PGE-2含量,血清中IL-1β、TNF-α含量,及软骨组织中MMP-1、MMP-13含量。结果实验期间模型组大鼠膝关节显著肿胀(P0.01),各给药组与模型组相比均有不同程度缓解。组方优化的阳和胶囊高、中剂量组能够显著降低膝关节灌洗液中NO、PGE-2含量(P0.01)、显著降低血清中IL-1β、TNF-α含量(P0.01)明显降低软骨组织中MMP-1、MMP-13含量(P0.05)。结论组方优化的阳和胶囊对碘乙酸钠诱导的大鼠骨关节炎具有治疗作用,其机制可能与降低膝关节灌洗液及血清中NO、PGE-2、IL-1β、TNF-α水平及软骨组织中MMP-1、MMP-13含量有关。     

白茶提取物对LPS诱导的RAW264.7细胞炎症的影响

慢性炎症是导致衰退性疾病和代谢综合征发生与发展的关键病理因素。本研究以细菌脂多糖(lipopolysaccharide,LPS)诱导RAW264.7细胞炎症作为模型,测定其细胞相对活力、吞噬活性、NO分泌量、iNOS与IL-6基因的相对表达,考察白茶提取物对LPS诱导的RAW264.7细胞炎症反应的影响。结果表明,10～50 dl滋g/mL白茶提取物能有效提高RAW264.7细胞的吞噬活性,抑制NO分泌(P0.05),且陈年白茶效果优于新白茶;白茶提取物能降低iNOS与IL-6 m RNA基因表达水平,并且呈剂量依赖型,效果与阳性药物组(吲哚美辛)效果相当。本研究揭示白茶提取物对炎症反应具有显著的抑制作用,为后续的炎症评价体系的建立和白茶功效研究建立基础。     

湖北青砖茶对IBS-D模型大鼠肠道敏感性的影响

研究了湖北青砖茶对腹泻型肠易激综合征(IBS-D)模型大鼠肠道的影响。结果表明,与正常组相比,模型组的痛阈值明显降低,血清中炎症因子前列腺素2(PGE2)、肿瘤坏死因子(TNF-α)、类胰蛋白酶的含量明显增加;与模型组比较,湖北青砖茶低剂量组、高剂量组能够显著升高痛阈值,而血清中炎症因子PGE2、TNF-α、类胰蛋白酶的含量显著降低,且具有剂量依赖性。由此表明湖北青砖茶可降低IBS-D模型大鼠的肠道敏感性,其作用机制可能与血清中PGE2、TNF-α和类胰蛋白酶含量的降低有关。     

人参皂苷Rb3对大鼠实验性脑缺血的保护作用

目的观察人参皂苷Rb3对大鼠实验性脑缺血的保护作用。方法建立大鼠结扎双侧颈总动脉伴低血压建立急性不完全性脑缺血模型．计算脑指数及脑含水量,测定血清超氧化物歧化酶（SOD）、一氧化氮合酶（NOS）活力及血清丙二醛（MDA）、一氧化氮（NO）含量,同时测定脑组织SOD、钠-钾-ATP酶（Na^＋-K^＋-ATPase）、钙-镁-ATP酶（Ca^2＋-Mg^2＋-ATPase）活力及MDA含量。结果人参皂苷Rb14、28mg／kg可明显降低脑指数及脑含水量,亦能降低血清和脑组织MDA、NO含量及NOS活性,提高SOD、Na^＋-K^＋-ATPa8e和Ca^2＋-Mg^2＋-ATPase活力。结论人参皂苷Rb3对大鼠实验性脑缺血具有明显保护作用,可能通过抑制脂质过氧化反应,提高抗氧化酶活性,改善细胞能量代谢等环节实现的。     

NO延缓果蔬成熟衰老与抗病机理研究进展

一氧化氮是具有生物活性和信号转导作用的易扩散小分子气体,果蔬细胞通过一氧化氮合酶(NOS)、硝酸还原酶或非生化反应途径产生NO。内源NO可通过抑制乙烯的生物合成和调控环化核苷酸在植物组织中的水平来延缓植物组织的成熟和衰老,延长果蔬贮藏货架期;NO还可诱导采后果蔬产生抗病防卫反应,提高果蔬的抗病胁迫能力。着重概述NO在果蔬采后延缓成熟衰老、诱导抗病等方面的作用及其机理研究进展。     

Improvement of Tissue Survival of Skin Flaps by 5α-Reductase Inhibitors: Possible Involvement of Nitric Oxide and Inducible Nitric Oxide Synthase

Background:

Skin flap grafting is a popular approach for reconstruction of critical skin and underlying soft tissue injuries. In a previous study, we demonstrated the beneficial effects of two 5α-reductase inhibitors, azelaic acid and finasteride, on tissue survival in a rat model of skin flap grafting. In the current study, we investigated the involvement of nitric oxide and inducible nitric oxide synthase (iNOS) in graft survival mediated by these agents.

Methods:

A number of 42 male rats were randomly allocated into six groups: 1, normal saline topical application; 2, azelaic acid (100 mg/flap); 3, finasteride (1 mg/flap); 4, injection of L-N^G-nitroarginine methyl ester (L-NAME) (i.p., 20 mg/kg); 5, L-NAME (20 mg/kg, i.p.) + azelaic acid (100 mg/flap, topical); 6, L-NAME (20 mg/kg, i.p.) + finasteride (1 mg/flap, topical). Tissue survival, level of nitric oxide, and iNOS expression in groups were measured.

Results:

Our data revealed that azelaic acid and finasteride significantly increased the expression of iNOS protein and nitric oxide (NO) levels in graft tissue (P < 0.05). These increases in iNOS expression and NO level were associated with higher survival of the graft tissue.

Conclusion:

It appears that alterations of the NO metabolism are implicated in the azelaic acid- and finasteride-mediated survival of the skin flaps.Key Words: Finasteride, Azelaic acid, Surgical flaps, Nitric oxide, Nitric oxide synthase Type II     

Immunostimulative Activity of Low Molecular Weight Chitosans in RAW264.7 Macrophages

Chitosan and its derivatives such as low molecular weight chitosans (LMWCs) have been reported to exert many biological activities, such as antioxidant and antitumor effects. However, complex and molecular weight dependent effects of chitosan remain controversial and the mechanisms that mediate these complex effects are still poorly defined. This study was carried out to investigate the immunostimulative effect of different molecular weight chitosan in RAW264.7 macrophages. Our data suggested that two LMWCs (molecular weight of 3 kDa and 50 kDa) both possessed immunostimulative activity, which was dependent on dose and, at the higher doses, also on the molecular weight. LMWCs could significantly enhance the the pinocytic activity, and induce the production of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), interferon-γ (IFN-γ), nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in a molecular weight and concentration-dependent manner. LMWCs were further showed to promote the expression of the genes including iNOS, TNF-α. Taken together, our findings suggested that LMWCs elicited significantly immunomodulatory response through up-regulating mRNA expression of proinflammatory cytokines and activated RAW264.7 macrophage in a molecular weight- and concentration-dependent manner.     

Anti-Inflammatory Activity of Tanzawaic Acid Derivatives from a Marine-Derived Fungus Penicillium steckii 108YD142

Chemical investigation of a marine-derived fungus, Penicillium steckii 108YD142, resulted in the discovery of a new tanzawaic acid derivative, tanzawaic acid Q (1), together with four known analogues, tanzawaic acids A (2), C (3), D (4), and K (5). The structures of tanzawaic acid derivatives 1–5 were determined by the detailed analysis of 1D, 2D NMR and LC-MS data, along with chemical methods and literature data analysis. These compounds significantly inhibited nitric oxide (NO) production and the new tanzawaic acid Q (1) inhibited the lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins and mRNA expressions in RAW 264.7 macrophages. Additionally, compound 1 reduced the mRNA levels of inflammatory cytokines. Taken together, the results of this study demonstrated that the new tanzawaic acid derivative inhibits LPS-induced inflammation. This is the first report on the anti-inflammatory activity of tanzawaic acid Q (1).     

Obtaining from Grape Pomace an Enzymatic Extract with Anti-inflammatory Properties

Grape pomace, a winemaking industry by-product, is a rich source of bioactive dietary compounds. Using proteases we have developed an enzymatic process for obtaining a water-soluble extract (GP-EE) that contains biomolecules such as peptides, carbohydrates, lipids and polyphenols in soluble form. Of especial interest is its high polyphenol content (12 %), of which 77 % are flavonoids and 33 % are phenolic acids. The present study evaluates in vitro the potential anti-inflammatory effect of GP-EE by monitoring the expression of inflammatory molecules on N13 microglia cells stimulated with lipopolysaccharide (LPS). GP-EE decreases the mRNA levels of the inflammatory molecules studied. The molecules under study were as follows: inducible nitric oxide synthase (iNOS), tumor necrosis factor- α (TNF-α), interleukin-1β (IL-1β), the ionized calcium binding adaptor molecule-1(Iba-1) and the Toll like receptor-4 (TLR-4), as well as the iNOS protein level in LPS-stimulated microglia. Our findings suggest that, as a result of its ability to regulate excessive microglial activation, GP-EE possesses anti-inflammatory properties. Therefore, acting as a chemopreventive agent, it may be of therapeutic interest in neurodegenerative diseases involving neuroinflammation. We can, therefore, propose GP-EE as a useful natural extract and one that would be beneficial to apply in the field of functional foods.

     

Modulation of Lipopolysaccharide Stimulated Nuclear Factor kappa B Mediated iNOS/NO Production by Bromelain in Rat Primary Microglial Cells

Background:

Microglial cells act as the sentinel of the central nervous system .They are involved in neuroprotection but are highly implicated in neurodegeneration of the aging brain. When over-activated, microglia release pro-inflammatory factors, such as nitric oxide (NO) and cytokines, which are critical in eliciting neuroinflammatory responses associated with neurodegenerative diseases. This study examined whether bromelain, the pineapple-derived extract, may exert an anti-inflammatory effect in primary microglia and may be neuroprotective by regulating microglial activation.

Methods:

Following the isolation of neonatal rat primary microglial cells, the activation profile of microglia was investigated by studying the effects of bromelain (5, 10, 20, and 30 µg/ml) on the levels of NO, inducible nitric oxide synthase (iNOS), and nuclear factor kappa B (NF-κB) in microglia treated with lipopolysaccharide (LPS) (1 µg/ml). Data were analyzed using Student''s t-test. P values less than 0.05 were considered to be statistically significant, compared with the LPS-treated group without bromelain.

Results:

Results showed that pretreatment of rat primary microglia with bromelain, decreased the production of NO induced by LPS (1 µg/ml) treatment in a dose-dependent manner. Bromelain (30 µg/ml) also significantly reduced the expression of iNOS at mRNA level and NF-κB at protein level. Moreover, the study of mitochondrial activity in microglia indicated that bromelain had no cytotoxicity at any of the applied doses, suggesting that the anti-inflammatory effects of bromelain are not due to cell death.

Conclusion:

Bromelain can be of potential use as an agent for alleviation of symptoms in neurodegenerative diseases.     

Anti-Inflammatory and Analgesic Effects of the Marine-Derived Compound Excavatolide B Isolated from the Culture-Type Formosan Gorgonian Briareum excavatum

In recent years, several marine-derived compounds have been clinically evaluated. Diterpenes are secondary metabolites from soft coral that exhibit anti-inflammatory, anti-tumor and cytotoxic activities. In the present study, we isolated a natural diterpene product, excavatolide B, from cultured Formosan gorgonian Briareum excavatum and investigated its anti-inflammatory activities. We found that excavatolide B significantly inhibited the mRNA expression of the proinflammatory mediators, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in lipopolysaccharide (LPS)-challenged murine macrophages (RAW 264.7). We also examined the anti-inflammatory and anti-nociceptive effects of excavatolide B on intraplantar carrageenan-induced inflammatory responses. Excavatolide B was found to significantly attenuate carrageenan-induced nociceptive behaviors, mechanical allodynia, thermal hyperalgesia, weight bearing deficits and paw edema. In addition, excavatolide B inhibited iNOS, as well as the infiltration of immune cells in carrageenan-induced inflammatory paw tissue.     

Sargachromenol Purified from Sargassum horneri Inhibits Inflammatory Responses via Activation of Nrf2/HO-1 Signaling in LPS-Stimulated Macrophages

In this study, we isolated sargachromenol (SC) from Sargassum horneri and evaluated its anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. SC did not show cytotoxicity at all concentrations and effectively increased the cell viability by reducing the nitric oxide (NO) and intracellular reactive oxygen species (ROS) production in LPS-stimulated RAW 264.7 macrophages. In addition, SC decreased the mRNA expression levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α) and inflammatory mediators (iNOS and COX-2). Moreover, SC suppressed the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and mitogen-activated protein kinase (MAPK) signaling, whereas activated the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling in LPS-stimulated RAW 264.7 macrophages. Interestingly, the anti-inflammatory effect of SC was abolished by the inhibition of HO-1 in LPS-stimulated RAW 264.7 macrophages. According to the results, this study suggests that the antioxidant capacity of SC leads to its anti-inflammatory effect and it potentially may be utilized in the nutraceutical and pharmaceutical sectors.