Protective effects of Scutellaria lindbergii root extract against oxidative-induced cell and DNA damage in mouse fibroblast-like cells

Context: Scutellaria lindbergii Rech. f. (Lamiaceae) is an Iranian species of Scutellaria which has been shown to exert antimicrobial, antioxidant and cytotoxic effects. Objective: The protective properties of total methanol extract (TME) of S. lindbergii and its fractions (defatted and CH₂Cl₂) were investigated against cytotoxic and genotoxic effects of H₂O₂ in NIH 3T3 cell line as non-malignant cells. Materials and methods: The cells were incubated with different concentrations of S. lindbergii root extracts [TME (15–250?μg ml^?1), defatted fraction (15–500?μg ml^?1) and CH₂Cl₂ fraction (5–40?μg ml^?1)] and toxic concentration of H₂O₂ (200?µM) at 37?°C for 2?h concurrently and Cell viability was quantitated by MTT assay. The antigenotoxic effect of extracts was investigated using comet assay. The cells were incubated with extracts [TME (25–250?μg ml^?1), defatted fraction (25–500?μg ml^?1) and CH₂Cl₂ fraction (5–40?μg ml^?1)] and H₂O₂ (25?µM) at 4?°C for 20?min, then the comet assay was performed. DNA damage was expressed as percentage tail DNA. Results: Total methanol extract of S. lindbergii and its fractions had a significant inhibitory effect on DNA damage. The IC₅₀ values of TME, defatted fraction and CH₂Cl₂ fraction against DNA damage were determined as 48, 138 and 8?μg ml^?1, respectively. Conclusion: S. lindbergii extracts can prevent oxidative DNA damage, which is likely due to its flavonoids and phenolic compounds as antioxidant constituents.     

Lineage-related and particle size-dependent cytotoxicity of chitosan nanoparticles on mouse bone marrow-derived hematopoietic stem and progenitor cells

Chitosan nanoparticles (CSNPs) have potential applications in stem cell research. In this study, ex vivo cytotoxicity of CSNPs on mouse bone marrow-derived (MBMCs) hematopoietic stem and progenitor cells (HSPCs) was determined. MBMCs were exposed to CSNPs of different particle sizes at various concentrations for up to 72 h. Cytotoxicity effect of CSNPs on MBMCs was determined using MTT, Live/Dead Viability/Cytotoxicity assays and flow cytometry analysis of surface antigens on HSCs (Sca-1⁺), myeloid-committed progenitors (CD11b⁺, Gr-1⁺), and lymphoid-committed progenitors (CD45⁺, CD3e⁺). At 24 h incubation, MBMCs' viability was not affected by CSNPs. At 48 and 72 h, significant reduction was detected at higher CSNPs concentrations. Small CSNPs (200 nm) significantly reduced MBMCs' viability while medium-sized particle (∼400 nm) selectively promoted MBMCs growth. Surface antigen assessment demonstrated lineage-dependent effect. Significant decrease in Sca-1⁺ cells percentage was observed for medium-sized particle at the lowest CSNPs concentration. Meanwhile, reduction of CD11b⁺ and Gr-1⁺ cells percentage was detected at high and intermediate concentrations of medium-sized and large CSNPs. Percentage of CD45⁺ and CD3e⁺ cells along with ROS levels were not significantly affected by CSNPs. In conclusion, medium-sized and large CSNPs were relatively non-toxic at lower concentrations. However, further investigations are necessary for therapeutic applications.     

Hydrogen‐Bonding Effects for the C–ON Bond Homolysis and Reformation Reactions of Alkoxyamines

N‐(2‐methylpropyl)‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐O‐(2‐carboxyprop‐2‐yl) hydroxylamine (BlocBuilder MA) is, among the commercially available alkoxyamines, one of the most efficient for nitroxide‐mediated polymerization (NMP). However, recent results have shown that it does not perform well for the NMP of isoprene. The occurrence of intramolecular hydrogen bonding (IHB) between the carboxylic function and the diethoxyphosphoryl group has been proposed as the reason for its low efficiency. In this article, the presence of this IHB is confirmed using IR, ³¹P NMR, ³¹P‐¹H HOESY, and DFT calculation results. The solvent effect on this IHB and consequently on k_d values is also investigated. However, combining kinetic analysis and rate measurements in various solvents, the influence of this IHB on the C? ON bond homolysis and reformation in alkoxyamine is shown to be very weak.

     

The Unusual Mechanical Evolution of Biodegradable Double Hydrogen Bonding Strengthened Hydrogels in Response to pH Change

Conventionally, biodegradable hydrogels end up with quick disintegration and consequently fail to bear external loading after degradation. Here, a biocleavable high‐strength hydrogel prepared by copolymerization of 2‐vinyl‐4,6‐diamino‐1,3,5‐triazine (alkali active H‐bonding monomer), 3‐acrylamidophenylboronic acid (acid active H‐bonding monomer), oligo(ethylene glycol) methacrylate, and crosslinker N,N′‐bis(acryloyl)cystamine is reported. The hydrogel is shown to be degraded after the disulfide bonds in the chemical crosslinkers are broken down in a reducible medium. Remarkably, the degraded hydrogel evolves into supramolecular network, which is strengthened by diaminotriazine–diaminotriazine and phenylboronic acid–phenylboronic acid dual H‐bonded physical crosslinks despite the loss of chemical crosslinking. It is demonstrated that over a broad pH range, the degraded hydrogels are able to retain macroscopic integrity and withstand high external loading due to the existence of at least one kind of hydrogen bonding crosslinking. This biodegradable double hydrogen bonding strengthened hydrogel may push forward the research on a new type of high‐strength hydrogels.

     

Roles of Cav3.2 and TRPA1 channels targeted by hydrogen sulfide in pancreatic nociceptive processing in mice with or without acute pancreatitis

Hydrogen sulfide (H₂S), formed by multiple enzymes, including cystathionine‐γ‐lyase (CSE), targets Ca_v3.2 T‐type Ca²⁺ channels (T channels) and transient receptor potential ankyrin‐1 (TRPA1), facilitating somatic pain. Pancreatitis‐related pain also appears to involve activation of T channels by H₂S formed by the upregulated CSE. Therefore, this study investigates the roles of the Ca_v3.2 isoform and/or TRPA1 in pancreatic nociception in the absence and presence of pancreatitis. In anesthetized mice, AP18, a TRPA1 inhibitor, abolished the Fos expression in the spinal dorsal horn caused by injection of a TRPA1 agonist into the pancreatic duct. As did mibefradil, a T‐channel inhibitor, in our previous report, AP18 prevented the Fos expression following ductal NaHS, an H₂S donor. In the mice with cerulein‐induced acute pancreatitis, the referred hyperalgesia was suppressed by NNC 55‐0396 (NNC), a selective T‐channel inhibitor; zinc chloride; or ascorbic acid, known to inhibit Ca_v3.2 selectively among three T‐channel isoforms; and knockdown of Ca_v3.2. In contrast, AP18 and knockdown of TRPA1 had no significant effect on the cerulein‐induced referred hyperalgesia, although they significantly potentiated the antihyperalgesic effect of NNC at a subeffective dose. TRPA1 but not Ca_v3.2 in the dorsal root ganglia was downregulated at a protein level in mice with cerulein‐induced pancreatitis. The data indicate that TRPA1 and Ca_v3.2 mediate the exogenous H₂S‐induced pancreatic nociception in naïve mice and suggest that, in the mice with pancreatitis, Ca_v3.2 targeted by H₂S primarily participates in the pancreatic pain, whereas TRPA1 is downregulated and plays a secondary role in pancreatic nociceptive signaling. © 2014 Wiley Periodicals, Inc.     

经皮穴位电刺激不同时间对雷公藤甲素致大鼠急性肝损伤的影响

目的 观察经皮穴位电刺激（transcutanclus electrical acupoint stimulation,TEAS）不同刺激时间对雷公藤甲素致大鼠急性肝损伤的保护作用。方法 将50只SD大鼠随机分为空白组、模型组、TEAS Ⅰ组（刺激20 min）,TEAS Ⅱ组（刺激30 min）、TEAS Ⅲ组（刺激40 min）,以雷公藤甲素灌胃法复制急性肝损伤模型。TEAS各组刺激“足三里”穴,每日1次,连续5 d。观察肝脏组织形态学变化,检测血清天冬氨酸氨基转移酶（aspartate aminotransferase,AST）、丙氨酸氨基转移酶（alanine aminotransferase,ALT）及肝组织丙二醛（malondialdehyde,MDA）、肿瘤坏死因子- α（tumor necrosis factor- α,TNF- α）、白介素- 10（interleukin- 10,IL- 10）、硫化氢的含量。结果 模型组大鼠肝索排列紊乱,肝窦扩张,肝细胞水肿、脂肪变性、坏死;各TEAS组肝脏病理变化较模型组减轻。与空白组比较,模型组大鼠血清ALT、AST及肝组织MDA、TNF- α含量明显升高（P＜0.05）,硫化氢含量明显降低（P＜0.05）,肝组织IL- 10含量无明显变化（P＞0.05）。与模型组比较,TEAS Ⅰ、Ⅱ、Ⅲ组大鼠血清AST、ALT含量和肝组织MDA、TNF- α含量明显降低（P<0.05）或呈降低趋势（P>0.05）,硫化氢含量明显升高（P<0.05）。其中TEAS Ⅲ组与TEAS Ⅰ、Ⅱ组各指标比较,差异均具有统计学意义（P＜0.05）。结论 TEAS能减轻雷公藤甲素对肝组织的损伤,且较长时间（40 min）刺激的保护作用更为明显。     

过氧化氢低温等离子体灭菌器及其生物指示物应用现状调查

目的了解医疗机构中过氧化氢低温等离子体灭菌器及其生物指示物的应用状况。方法采用问卷调查和现场查看形式,对江苏省部分医疗机构使用中的过氧化氢低温等离子体灭菌器及其生物指示剂生物负载进行调查与测试。结果共调查江苏省市级医疗机构97家,其中67家拥有过氧化氢低温等离子体灭菌器,拥有率为88.16%。过氧化氢低温等离子体灭菌器的灭菌效果均采用生物指示剂进行定期监测,所使用的生物指示剂的回收菌量合格率为35.48%。结论江苏省医疗机构过氧化氢低温等离子体灭菌器拥有率较高,其灭菌效果监测专用生物指示剂多数不符合标准,亟待规范。     

A High‐Sensitivity Coumarin‐Based Fluorescent Probe for Monitoring Hydrogen Sulfide in Living Cells

A novel coumarin‐based fluorescence probe has been constructed for the selective and sensitive detection of hydrogen sulfide (H₂S). This probe displays high sensitivity and linearity to H₂S in degassed PBS buffers and fetal bovine serum. It reacts with H₂S with high selectivity over Cys, GSH, and other anions. Meanwhile, successful detection of H₂S in living cells was also demonstrated.     

Caco-2 cell metabolism of oxygen-derived radicals

Reactive oxygen metabolites have been associated with gastrointestinal injury and may play a role as mediators of inflammation. The effect of oxygen metabolites on Caco-2 cell viability (trypan blue exclusion and⁵¹Cr release), hexose monophosphate shunt activity, and glutathione was assessed. Caco-2 cells were incubated with amino acid oxidase, xanthine oxidase, menadione, andt-butylhydroperoxide in the presence and absence of superoxide dismutase, catalase, mannitol, and butylated hydroxytoluene. With amino acid oxidase, trypan blue exclusion decreased (P<0.01) and⁵¹Cr release, oxidized glutathione, and shunt activity increased (P<0.05). The addition of catalase attenuated these changes. Trypan blue exclusion decreased (P<0.005) and⁵¹Cr release, oxidized glutathione, and shunt activity increased (P<0.01) with xanthine oxidase. The addition of superoxide dismutase caused a further increase in⁵¹Cr release, oxidized glutathione, and shunt activity (P<0.01), which was prevented by the addition of catalase or mannitol.t-Butylhydroperoxide did not effect⁵¹Cr release or trypan blue exclusion, but oxidized glutathione and shunt activity increased (P<0.01). The increase in shunt activity was prevented by preincubation with butylated hydroxytoluene (P<0.01). Menadione did not alter trypan blue exclusion or⁵¹Cr release, but caused an increase in oxidized glutathione and shunt activity (P<0.001). The increase in shunt activity was attenuated by preincubation with butylated hydroxytoluene (P<0.001). Menadione also caused a depletion of total glutathione. Thus, Caco-2 cells are sensitive to oxidant injury and in all four systems increase in shunt activity and oxidized glutathione occurred at concentrations lower than those that caused cell injury, suggesting the shunt via the glutathione cycle is important in Caco-2 cell metabolism of oxidant species.S. Baker was supported by a grant from the Crohns and Colitis Foundation of America and the USDA, #9000763.     

益肾活血方联合氯沙坦对维持性血液透析患者内源性硫化氢及炎症细胞因子的影响

目的:观察益肾活血方联合氯沙坦治疗对维持性血液透析患者内源性硫化氢、炎症细胞因子以及血管内皮细胞功能的影响。方法:将90例维持性血液透析患者随机抽样法分为益肾活血方组、氯沙坦组、联合用药组,每组各30例,检测患者治疗前后血清总胆固醇(TC),甘油三脂(TG),低密度脂蛋白(LDL-C),同型半胱氨酸(Hcy),高敏C反应蛋白(hs-CRP),硫化氢(H2S),硫化血红蛋白(SHb),血浆内皮素(ET-1),一氧化氮(NO),肿瘤坏死因子α(TNF-α),白介素6(IL-6)水平和血流介导性内皮舒张功能(FMD)。结果:联合用药组[TC(3.68±0.85)mmol·L-1,LDL-C(2.07±1.61)mmol·L-1,Hcy(31.76±17.23)μmol·L-1]水平较治疗前明显下降[(5.29±1.28)mmol·L-1,(3.45±1.84)mmol·L-1,(35.97±18.23)μmol·L-1],差异具统计学意义(P0.05);hs-CRP(15.23±4.01)mg·L-1,H2S(9.81±5.61)nmol·L-1,SHb(5.58±1.29)%,ET-1(20.77±10.01)ng·mol-1,NO(17.42±8.81)μmol·L-1,TNF-α(39.6±6.53)ng·L-1,IL-6(37.6±3.51)ng·L-1水平和FMD(10.05±.3.56)%较治疗前显著改善[(19.13±6.18)mg·L-1,(5.51±3.24)nmol·L-1,(2.04±0.49)%,(25.39±14.26)ng·mol-1,(13.14±6.59)μmol·L-1,(42.4±7.61)ng·L-1,(40.6±4.62)ng·L-1,(6.67±1.94)%],差异有统计学意义(P0.01)。结论:益肾活血方联合氯沙坦能显著改善维持性血透患者血管内皮细胞功能损伤。