Antioxidant activity of the oyster mushroom, Pleurotus ostreatus, on CCl4-induced liver injury in rats

This study was undertaken to investigate the putative antioxidant activity of the oyster mushroom Pleurotus ostreatus on CCl₄-induced liver damage in male Wistar rats. Intraperitoneal administration of CCl₄ (2 ml/kg) to rats for 4 days resulted in significantly elevated (p < 0.05) serum levels of glutamic oxaloacetic transaminase (SGOT), glutamic pyruvate transaminase (SGPT) and alkaline phosphatase (SALP) compared to controls. In the liver, significantly elevated levels (p < 0.05) of malondialdehyde (MDA) and lowered levels (p < 0.05) of reduced glutathione (GSH) were observed following CCl₄ administration. Quantitative and qualitative analysis of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) revealed lower activities of these antioxidant enzymes in the liver of CCl₄-administered rats. An analysis of the isozyme pattern of these enzymes revealed variations in relative concentration presumably due to hepatotoxicity. When rats with CCl₄-induced hepatotoxicity were treated with the extract of P. ostreatus, the serum SGOT, SGPT and SALP levels reverted to near normal, while the hepatic concentration of GSH, CAT, SOD and Gpx were significantly increased (p < 0.05) and that of MDA significantly (p < 0.05) lowered, when compared to CCl₄-exposed untreated rats. Histopathological studies confirmed the hepatoprotective effect conferred by the extract of P. ostreatus. These results suggest that an extract of P. ostreatus is able to significantly alleviate the hepatotoxicity induced by CCl₄ in the rat.     

人参蛋白协同H2O2诱导SH-SY5Y细胞氧化损伤

目的:探讨人参蛋白(GP)协同H₂O₂诱导人神经母细胞瘤(SH-SY5Y)氧化应激损伤的作用,并筛选二者的最佳联合浓度。方法:首先采用不同浓度H₂O₂诱导SH-SY5Y细胞氧化损伤,然后采用不同浓度GP联合200 μmol·L^-1H₂O₂诱导SH-SY5Y细胞氧化损伤;采用倒置荧光显微镜观察细胞形态,MTT法检测细胞存活,Hoechst 33342染色法检测细胞凋亡。结果:SH-SY5Y细胞经GP-H₂O₂作用后,细胞数量减少,轴突缩短或消失,胞体变圆、缩小,大小不等;细胞存活率降低;Heochst 33342染色呈现高蓝光;GP 60 mg·L^-1+H₂O₂ 200 μmol·L^-1为联合诱导氧化应激损伤的最佳浓度。结论:GP有协同H₂O₂诱导SH-SY5Y细胞氧化损伤的作用,抑制细胞增殖、促进细胞凋亡是其可能的作用机制。     

Evaluation of oxidative damage and inhibition of DNA repair in an in vitro study of nickel exposure

It has been suggested that Nickel is involved in oxidative damage and inhibition of DNA repair. We studied the effects of NiSO₄ on oxidative stress and DNA repair in Jurkat cells to elucidate its mechanism of action. Cells were treated with H₂O₂ and ROS generation (by flow cytometry), and oxidative DNA damage (as tail moment by Fpg-enzyme comet test), were evaluated immediately and after 4 and 24 h of DNA damage recovery occurred in presence or absence of NiSO₄ (0.017 and 0.17 μ ) to clarify possible interactions of Ni with DNA repair processes. Moreover, cells were exposed to the same doses of NiSO₄ for 4 and 24 hours to evaluate its direct oxidative effect. The results of the comet test showed high tail moment immediately after oxidative burst with a decreasing after 4 h of DNA recovery, and a slight increase after 24 h of recovery. The decreases were more limited for cells treated with NiSO₄ 0.17 μ indicating an inhibition of oxidative DNA damage repair by this substance. An induction of ROS was observed after 4 h of incubation with higher dose of NiSO₄. Cells treated with H₂O₂ showed the highest level of ROS after 4 h of recovery in presence of NiSO₄ 0.17 μ that remained at elevated levels also after 24 h of recovery suggesting a synergistic action of Ni with H₂O₂ in the reduction of cellular anti-oxidative defence activities.     

Antioxidative potential of melatonin against mercury induced intoxication in spermatozoa in vitro

Mercury is one of the most investigated natural elements and potential contaminants in the environment. Antioxidants have long been known to reduce the free radical-induced oxidative damage. Considering the antioxidant properties of melatonin, this study was aimed to evaluate the effect of melatonin on antioxidant system of rat epididymal sperm in vitro. Sperm samples were dispersed in RPS medium (pH 6.9) and incubated with mercury in the form of mercuric chloride (MC) at three different concentrations (1 μM, 10 μM, 100 μM), melatonin (MLT) at a concentration (100 μM) and mercuric chloride+melatonin (100 μM each) for 3 h at 32 °C. Sperm viability and motility were assessed every 30 min during the 3-h incubation period. An aliquot of sperm sample was homogenised, centrifuged and used for the assay of superoxide dismutase, glutathione peroxidase, glutathione reductase, TBARS assay to detect lipid peroxidation and hydrogen peroxide generation assay. Samples treated with mercury showed a dose-dependent decrease in motility while there was no significant decrease in sperm viability. In mercury-incubated sperm, the activity of superoxide dismutase, glutathione peroxidase and glutathione reductase decreased significantly while TBARS levels and H₂O₂ generation were increased in a dose-dependent manner. Co-incubation of sperm with mercury and melatonin exhibited no significant changes in the levels of motility, viability and antioxidant indices as compared to untreated controls. The results suggest that graded doses of mercury elicit depletion of antioxidant defense system in sperm without altering the viability and melatonin treatment was found to significantly inhibit oxidative damage caused by mercury.     

Protective effects of Hibiscus tiliaceus L. methanolic extract to V79 cells against cytotoxicity and genotoxicity induced by hydrogen peroxide and tert-butyl-hydroperoxide

Plants of the genus Hibiscus thrives produce a diversity of molecules with bioactive properties. In a previous study of Hibiscus tiliaceus L. methanolic extract (HME) using bacteria and yeast, as test media, it has been shown that HME strongly inhibited the mutagenic action of H₂O₂ or tert-butyl-hydroperoxide (t-BHP). Here, our interest is to evaluate the genotoxicity and the antigenotoxic/antimutagenic properties of HME using oxidative challenge with H₂O₂ and t-BHP in V79 cells. We determined cytotoxicity using clonal survival assay; evaluated DNA damage using the comet assay and the micronucleus test in binucleated cells besides of the lipid peroxidation degree and the reduced glutathione content. We examined the ability of HME in quenching hydroxyl radical by means of a HPLC-based method utilizing the hypoxanthine/xanthine oxidase assay. At concentrations ranging from 0.001 to 0.1 mg/mL, HME was not cytotoxic, genotoxic or mutagenic. Treatment with non-cytotoxic concentrations of HME increased cell survival after H₂O₂ and t-BHP exposure and prevented DNA damage. The pre-treatment with HME also was able to decrease the mutagenic effect of these genotoxins, evaluated using the micronucleus test. HME prevented the increase in lipid peroxidation and decrease in GSH content in response to the oxidative challenge. Therefore, the ability in preventing against H₂O₂- and t-BHP-induced GSH depletion and lipid peroxidation was probably a major contribution to the cytoprotective effects. Moreover, HME acts as a hydroxyl radical scavenger. In summary, HME did not have a harmful or inhibitory effect on the growth of V79 cells and presented antioxidant activity, consequently, both antigenotoxic and antimutagenic effects against oxidative DNA damage.     

Inhibition of the myeloperoxidase chlorinating activity by non-steroidal anti-inflammatory drugs: flufenamic acid and its 5-chloro-derivative directly interact with a recombinant human myeloperoxidase to inhibit the synthesis of hypochlorous acid

The present in vitro study was designed to assess the inhibition of the myeloperoxidase (MPO)/H₂O₂/Cl⁻ system by several non steroidal anti-inflammatory drugs (NSAIDs) of the oxicam family and of nimesulide and to compare their effect with flufenamic acid in order to investigate their influence on the chlorinating activity of MPO as a protective mechanism during chronic inflammatory syndromes. The inhibition of the system was assessed by measurement of the taurine chlorination while the accumulation of compound II was used to investigate the mechanism of inhibition. The oxidation products of NSAIDs by the MPO/H₂O₂/Cl⁻ system were identified and flufenamic acid and derivatives were also assessed in the inhibition of LDL oxidation in two models. Flufenamic acid (IC₅₀ = 1.1 ± 0.3 μM) is the most efficient inhibitor of the MPO/H₂O₂/Cl⁻ system and nimesulide (IC₅₀ = 2.1 ± 0.3 μM) is more active than the other NSAIDs of the oxicam family (IC₅₀ = 8–12 μM). The accumulation of compound II revealed that flufenamic acid acts as an electron donor while the other NSAIDs are antagonists of chloride anions. The identification of the oxidation products confirms that flufenamic behaves like an electron donor and is directly oxidized in the 5-hydroxy-derivative but gives also the 5-chloro-derivative which similarly inhibits the MPO/H₂O₂/Cl⁻ system. Flufenamic acid has the best inhibiting activity towards the MPO/H₂O₂/Cl⁻ system. However, in models that assess the LDL oxidation, flufenamic acid and its derivatives were unable to properly inhibit MPO activity as the enzyme is adsorbed on macrostructures such as LDL molecules.     

曲美他嗪对内皮祖细胞氧化应激损伤的保护作用研究

目的: 研究曲美他嗪(TMZ)对过氧化氢(H₂O₂)诱导的内皮祖细胞(EPCs)氧化应激损伤的保护作用。方法: 采用密度梯度离心法分离人脐带血单个核细胞,使用EBM-2完全培养基诱导单个核细胞向内皮祖细胞分化,经细胞形态学变化及流式细胞术测定内皮祖细胞特异性标记物CD133、CD34和VEGFR抗原来鉴定内皮祖细胞。体外建立内皮祖细胞过氧化氢(100 μmol·L^-1)损伤模型,加入不同浓度曲美他嗪(0.1,0.5,1,5 μmol·L^-1),观察曲美他嗪作用不同时间后(0.5,1,6,12 h)内皮祖细胞增殖、黏附、迁移、一氧化氮(NO)分泌能力的变化。结果: 曲美他嗪呈剂量及时间依赖性降低过氧化氢对内皮祖细胞的氧化应激损伤,保护内皮祖细胞增殖、黏附、迁移、分泌的生物学功能。结论: 曲美他嗪在氧化应激条件下对内皮祖细胞生物学功能的保护可能是其心血管保护作用的机制之一。     

Assessment of the DNA damaging potency and chemopreventive effects towards BaP-induced genotoxicity in human derived cells by Monimiastrum globosum, an endemic Mauritian plant

Naturally occurring compounds have protective effects towards mutagens and carcinogens. The leaf extract of Monimiastrum globosum (Bois de Clous), a Mauritian endemic plant from the Myrtaceae family, was studied for its potency to induce DNA damage in human HepG2 hepatoma cells using DNA migration as a biological endpoint in the alkaline single cell gel electrophoresis (SCGE) assay. This was contrasted with the ability to modulate the benzo[a]pyrene (BaP)-dependent DNA damage in human hepatoma cells. M. globosum caused genotoxicity in HepG2 cells at concentrations exceeding 3 mg fresh weight (FW) per ml cell culture in the absence of cytotoxicity. Pre-treatment of the cells with 12.2 μg FW/ml to 1.56 mg FW/ml led to a pronounced antigenotoxic effect towards BaP-induced DNA damage. DNA migration (OTM) was reduced by 66%, 81.5% and 74% for 49, 98 and 195 μg FW/ml, respectively. A U-shaped dose-response curve was derived for M. globosum indicating genotoxic effects in high doses and antigenotoxic effects in low doses. M. globosum extract had total phenolics (15 mg/g FW) with flavonoids (aglycones and conjugates: 8 mg/g FW) and proanthocyanidins (3 mg/g FW) as major phenolic subclasses. The hydrolysis of conjugated flavonoids yielded the aglycones quercetin (606 μg/g FW) and kaempferol (117.8 μg/g FW) while HPLC-MS/MS analysis of the total extract revealed free flavonoids such as quercetin (19.2 μg/g FW) and myricetin (2.5 μg/g FW). The antioxidant activity of the extract of M. globosum, assessed by the FRAP and TEAC assays yielded values of 275 ± 3.82 μmol/g FW and 346 ± 4.2 μmol/g FW, respectively.     

Effects of Brussels sprouts extracts on hydrogen peroxide-induced DNA strand breaks in human lymphocytes

Aqueous Brussels sprouts extracts inhibit oxidation of isolated DNA in vitro, possibly through scavenging oxygen radicals. We have studied the effect of preincubating human lymphocytes with aqueous extracts of raw, cooked and autolysed Brussels sprouts and the glucosinolate, sinigrin, on hydrogen peroxide-induced DNA damage, strand breaks and base oxidation, in vitro by means of the Comet assay. DNA repair enzymes endonuclease III (EndoIII) and formamidopyrimidine–DNA glycosylase (FPG) were used to examine the levels of oxidised pyrimidines and purines in DNA, respectively. Aqueous extracts of cooked and autolysed Brussels sprouts and sinigrin decreased DNA strand breaks in human lymphocytes exposed to 100 μ H₂O₂ for 5 min on ice, although the level of EndoIII and FPG sensitive sites was not reduced. The maximum inhibition was by 38 and 39% at concentrations of cooked and autolysed extracts of 10 μg/ml and 5 μg/ml, respectively, whereas the inhibitory effect decreased with increasing concentrations up to 100 μg/ml. The maximum inhibition by sinigrin was by 54% at 2 μg/ml. Extracts of raw Brussels sprouts or green beans had no DNA-protective effect. The results indicate that compounds, including sinigrin, in cooked and autolysed Brussels sprouts can enhance lymphocyte resistance towards H₂O₂-induced DNA strand breaks in vitro.     

In vitro induction of cytotoxicity and DNA strand breaks in CHO cells exposed to cypermethrin, pendimethalin and dichlorvos

The indiscriminate use of pesticides and herbicides to increase crop productivity has aroused a great concern among the environmental and health scientists due to their adverse effects in both target as well as non-target species. Although substantial information is available regarding their environmental and ecological impact, not much is known in regard to its toxicity in the mammalian system. Therefore a study was conducted for the assessment of cytotoxic and genotoxic effects of cypermethrin (Type II pyrethroid) dichlorvos (organophosphate) and pendimethalin (dinitroaniline herbicide) in Chinese hamster ovary (CHO) cells. CHO cells were exposed to 1 μM, 10 μM, 100 μM, 1000 μM, and 10,000 μM, cypermethrin, pendimethalin and dichlorvos for 3 h and cytotoxicity was assessed by MTT assay. Their genotoxic potential was also evaluated by Comet assay. The results demonstrate that dichlorvos and pendimethalin exhibited higher extent of cytotoxicity as compared to cypermethrin. A significant (p < 0.05) concentration dependent increase in DNA damage was observed with dichlorvos (0.01 μM and above) and pendimethalin (0.1 μM and above) as evident by Comet assay parameters viz., Olive tail moment (arbitrary units), tail DNA (%) and tail length (μM). Cypermethrin induced a significant (p < 0.05) DNA damage only at higher concentrations (1000 and 5000 μM). Our data indicates that these chemicals produce cytotoxicity and DNA damage in mammalian cells and should be used with caution.     

Concentration-dependent accumulation of [H]-deltamethrin in sodium channel Nav1.2/β1 expressing Xenopus laevis oocytes

Disruption of neuronal voltage-sensitive sodium channels (VSSCs) by pyrethroid insecticides such as deltamethrin (DLT) has been widely studied using Xenopus laevis oocytes transfected with VSSC. However, the extent of pyrethroid accumulation in VSSC-expressing oocytes is unknown. Therefore, accumulation of [³H]-DLT in non-transfected, sham (water)-transfected and VSSC (Na_v1.2 + β₁)-transfected oocytes after a 1 h exposure was measured using liquid scintillation counting. Successful transfection of Na_v1.2 + β₁ VSSCs in X. laevis oocytes was confirmed by two-electrode voltage-clamp; inward, tetrodotoxin (TTX)-sensitive currents were obtained in 98% of all oocytes examined (n = 60 in nine experiments). DLT (1.0 μM) induced tail currents in all VSSC-transfected oocytes; TTX also blocked these DLT-induced tail currents. In 0.1 μM DLT solution, non-transfected oocytes accumulated 0.098 ± 0.01 ppm [³H]-DLT, sham-transfected oocytes accumulated 0.06 ± 0.01 ppm DLT, and VSSC-transfected oocytes accumulated 0.050 ± 0.009 ppm DLT. In 1.0 μM DLT solution, non-transfected oocytes accumulated 0.62 ± 0.08 ppm DLT, sham-transfected oocytes accumulated 0.60 ± 0.09 ppm DLT, and VSSC-transfected oocytes accumulated 0.51 ± 0.07 ppm DLT. There was a significant difference in DLT accumulation between VSSC-transfected oocytes and non-transfected controls, where the transfected oocytes consistently had less accumulation.     

In vitro models of oxidative stress in rat erythrocytes: Effect of antioxidant supplements

The present study was designed to induce oxidative stress in lipid and aqueous phases through azo bis(2-amidinopropane)dihydrochloride (AAPH), 2,2′-azobis 2,4-dimethylvaleronitrile (ADVN) and hydrogen peroxide (H₂O₂) either alone or in combination with vitamin C or vitamin El and to assess the vulnerability of rat erythrocytes to oxidative stress. While AAPH acted equally on cell membrane and cytosol, ADVN increased OS in the membrane. The extent of hemolysis and increased membrane fragility caused was more in the case of azo compounds than of H₂O₂. While vitamin E (2 mM) reduced oxidative stress in the membrane, vitamin C (60 mM) was more effective in the lysates. The concentration of malondialdehyde and advanced oxidation protein products was lowered by antioxidants. The level of lipofuscin, a product of lipid peroxidation was also increased by ADVN and H₂O₂. Antioxidants, did, however, reduce the accumulation of protein carbonyl content in cells exposed to azo compounds although they were ineffective in inhibiting oxidation of membrane band 3 protein and sulphydryl content. Taken together, our study demonstrated the antioxidative property of vitamin E and vitamin C in reducing oxidative stress in aqueous as well as lipid phases of erythrocytes and further suggested the feasibility of in vitro models in evaluating the mechanisms of oxidative injury.     

美洲大蠊提取物对H2O2诱导的PC12细胞氧化损伤的保护作用

目的:探讨美洲大蠊提取物(PAS840)对大鼠肾上腺嗜铬细胞瘤(PC12)细胞氧化损伤模型的保护作用及机制。方法:采用H₂O₂刺激PC12细胞建立神经细胞氧化损伤模型,实验分为正常组(Con)、模型组(Mod)、PAS840低中高剂量组(20,50,125 μg·mL^-1的PAS840培养基溶液进行处理),采用倒置显微镜观察细胞形态并采用CCK-8法检测各组细胞存活率,生化试剂盒检测各组超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、乳酸脱氢酶(LDH)、谷胱甘肽(GSH)和丙二醛(MDA)的水平;DCFH-DA荧光探针检测各组活性氧簇(ROS)的水平;流式细胞术检测各组细胞凋亡率;JC-1法染色检测各组细胞线粒体膜电位(MMP);RT-qPCR检测各组Nrf2/HO-1通路因子(Nrf2、Keap1、HO-1和NQO1)、凋亡因子(Bcl-2、Bax和Caspase-3)、炎症因子(TNF-α、IL-1β和IL-6)、乙酰胆碱酯酶(AchE)和过氧化氢酶(CAT) mRNA的表达水平;Western blot法检测各组Nrf2、HO-1、Bcl-2、Bax和Caspase-3蛋白的表达水平。结果:PAS840可显著提高氧化损伤细胞的存活率、MMP及SOD、GSH-Px和GSH的水平,降低LDH、MDA和ROS的水平;显著降低Keap1、TNF-α、IL-1β、IL-6和AchE mRNA表达的同时,显著增加CAT和NQO1 mRNA的表达,显著降低Nrf2、Bax和Caspase-3的mRNA及其蛋白表达,显著增加HO-1和Bcl-2的mRNA及其蛋白表达。结论:PAS840可以抑制H₂O₂诱导的PC12细胞凋亡,减轻炎症,其机制可能与降低ROS、调控Nrf2/HO-1通路因子减轻细胞的氧化损伤程度有关。     

特异性敲低海马RNA甲基转移酶Pcif1对空间学习记忆的影响与机制研究

目的 探索RNA甲基转移酶Pcif1对海马相关空间学习记忆的影响及分子机制。方法 选择27只8周龄的雄性C57BL/6J Nifdc小鼠进行动物实验,随机分为3组（每组9只）：Pcif1敲低组（对小鼠海马立体定位注射1 μL的腺相关病毒包装的靶向Pcif1的shRNA）、假手术组（对小鼠海马立体定位注射1 μL的对照腺...     

Toona sinensis extracts induces apoptosis via reactive oxygen species in human premyelocytic leukemia cells

Toona sinensis (T. sinensis), well known in Taiwan as a traditional Chinese medicine, has been shown to exhibit antioxidant effects. In this study, therefore, the ability of T. sinensis to induce apoptosis was studied in cultured human premyelocytic leukemia HL-60 cells. Treatment of the HL-60 cells with a variety of concentrations of the aqueous extracts of T. sinensis (TS extracts) (10–75 μg/ml) and gallic acid (5–10 μg/ml), the natural phenolic components purified from TS extracts, resulted in dose- and time-dependent sequences of events marked by apoptosis, as shown by loss of cell viability and internucleosomal DNA fragmentation. Furthermore, apoptosis in the HL-60 cells was accompanied by the release of cytochrome c, caspase 3 activation and specific proteolytic cleavage of poly (ADP-ribose) polymerase (PARP). This increase in TS extracts- and gallic acid-induced apoptosis was also associated with a reduction in the levels of Bcl-2, a potent cell-death inhibitor, and an increase in those of the Bax protein, which heterodimerizes with and thereby inhibits Bcl-2. Interestingly, TS extracts- and gallic acid-induced dose-dependent reactive oxygen species (ROS) generation in HL-60 cells. We found that catalase significantly decreased TS extracts- or gallic acid-induced cytotoxicity, DNA fragmentation, and ROS production, however, slight reduction was observed with vitamins C and E. Our results indicate that TS extracts- or gallic acid-induced HL-60 apoptotic cell death could be due to the generation of ROS, especially H₂O₂. The data suggest that T. sinensis exerts antiproliferative action and growth inhibition on HL-60 cells through apoptosis induction, and, therefore, that it may have anticancer properties valuable for application in food and drug products.     

Effects of herbal products and their constituents on human cytochrome P4502E1 activity

Ethanolic extracts from fresh Echinacea purpurea and Spilanthes acmella and dried Hydrastis canadensis were examined with regard to their ability to inhibit cytochrome P450_2E1 mediated oxidation of p-nitrophenol in vitro. In addition, individual constituents of these extracts, including alkylamides from E. purpurea and S. acmella, caffeic acid derivatives from E. purpurea, and several of the major alkaloids from H. canadensis, were tested for inhibition using the same assay. H. canadensis (goldenseal) was a strong inhibitor of the P450_2E1, and the inhibition appeared to be related to the presence of the alkaloids berberine, hydrastine and canadine in the extract. These compounds inhibited 2E1 with K_I values ranging from 2.8 μM for hydrastine to 18 μM for berberine. The alkylamides present in E. purpurea and S. acmella also showed significant inhibition at concentrations as low as 25 μM, whereas the caffeic acid derivatives had no effect. Commercial green tea preparations, along with four of the individual tea catechins, were also examined and were found to have no effect on the activity of P450_2E1.     

Propofol, an anesthetic possessing neuroprotective action against oxidative stress, promotes the process of cell death induced by H2O2 in rat thymocytes

Propofol (2,6-diisopropylphenol) is a general anesthetic possessing a neuroprotective action against oxidative stress produced by H₂O₂. H₂O₂ induces an exposure of phosphatidylserine on outer surface of cell membranes, resulting in change in membrane phospholipid arrangement, in rat thymocytes. Since propofol is highly lipophilic, the agent is presumed to interact with membrane lipids and hence to modify the cell vulnerability to H₂O₂. Therefore, to test the possibility, we have examined the effect of propofol on rat thymocytes simultaneously incubated with H₂O₂. Although propofol (up to 30 μM) alone did not significantly affect the cell viability, the agent at 10 μM started to increase the population of dead cells in the presence of 3 mM H₂O₂ and the significant increase was observed at 30 μM. Propofol at clinically relevant concentrations (10–30 μM) facilitated the process of cell death induced by H₂O₂ in rat thymocytes. However, propofol protected rat brain neurons against the oxidative stress induced by H₂O₂ under same experimental condition. Therefore, the action of propofol may be dependent on the type of cells.     

NCX 6560, a nitric oxide-releasing derivative of atorvastatin, inhibits cholesterol biosynthesis and shows anti-inflammatory and anti-thrombotic properties

We compared the lipid-lowering, vasodilating, anti-thrombotic and anti-inflammatory properties of NCX 6560, a novel NO-releasing derivative of atorvastatin, with those of atorvastatin. NCX 6560 and atorvastatin induced similar inhibition of cholesterol biosynthesis in rat smooth muscle cells (IC₅₀ = 1.9 ± 0.4 and 3.9 ± 1.0 μM, respectively). However, in hyperlipidemic mice, a 5-week oral treatment with NCX 6560 (46.8 mg/kg/day, p.o.) was more effective than equivalent atorvastatin (40 mg/kg/day, p.o.) at lowering serum cholesterol (NCX 6560: − 21% vs controls, P < 0.05; atorvastatin: − 14% vs control, P = NS). In norepinephrine-precontracted rabbit aortic rings, NCX 6560-induced vasodilation (EC₅₀ = 53.5 ± 8.3 μM) and in PC12 cells it stimulated cGMP formation (EC₅₀ = 1.8 ± 0.7 μM), while atorvastatin was inactive. In lipopolysaccharide from Escherichia coli (LPS)-treated RAW 264.7 macrophages, NCX 6560 reduced iNOS expression and dimer assembly more efficiently than atorvastatin and inhibited nitrite accumulation (IC₅₀ = 6.7 ± 1.6 μM) and TNF release. U46619- or collagen plus epinephrine-induced platelet pulmonary thromboembolism in mice was reduced by NCX 6560 at 46.8 mg/kg p.o. (mortality: − 44% and − 56% vs vehicle, respectively; P < 0.05), but not by atorvastatin 40 mg/kg, p.o. In the U46619-induced mortality model, isosorbide mononitrate (ISMN) (20 mg/kg, p.o.), a pure NO-donor, was also active (mortality: − 40%, P < 0.05). NCX 6560 significantly reduced ex vivo platelet adhesion to collagen at high shear (− 31 ± 1.3% vs vehicle), and so did ISMN (− 33.3 ± 1.7% vs vehicle). Atorvastatin was ineffective. NCX 6560, but not atorvastatin, reduced blood pressure in eNOS knockout mice (− 16%, P < 0.001 vs vehicle), an effect not observed in wild type mice. On the contrary, ISMN provoked a significant drop of blood pressure both in wild type (− 20%, P < 0.05 vs vehicle) and in eNOS−/− mice (− 21%, P < 0.05 vs vehicle). In conclusion, NCX 6560 exerts greater lipid-lowering, anti-thrombotic and anti-inflammatory effects than atorvastatin, due to a large extent to NO release.     

Microcalorimetric investigation of the toxic action of ammonium ferric(III) sulfate on the metabolic activity of pure microbes

A series of calorimetric experiments were performed to investigate toxic action of ammonium ferric sulfate (AFS) on Bacillus subtilis, Pseudomonas putida and Candida humicola. The power–time curves of micro-organism metabolism were obtained, and the action of them by addition of AFS was studied. C. humicola, B. subtilis and P. putida were inhibited completely when the concentrations were up to 320.0, 160.0 and 160.0 μg mL⁻¹, respectively. The relationships between growth rate constant (k) and doses of AFS were approximately linear for three microbes, P. putida for 10.0–160.0 μg mL⁻¹ (R = −0.9746), B. subtilis for 0–160.0 μg mL⁻¹ (R = −0.9868) and C. humicola for 10.0–320.0 μg mL⁻¹ (R = −0.9955). The total heat dissipated per milliliter (Q_T) for three microbes remained balance approximately during the lower doses, P. putida and B. subtilis less than the dose of 20.0 μg mL⁻¹, 0.56 ± 0.01 and 0.26 ± 0.01 J mL⁻¹, respectively, C. humicola less than the dose of 40.0 μg mL⁻¹, 0.58 ± 0.03 J mL⁻¹. The biomass and OD₆₀₀ of three micro-organisms growth in the absence of AFS also were obtained. The power–time curve of C. humicola growth coincided with its turbidity curve. It elucidates that microcalorimetric method agreed with the routine microbiology method.     

Human percutaneous absorption of a direct hair dye comparing in vitro and in vivo results: Implications for safety assessment and animal testing

Although in vitro skin absorption studies often detect small residues of applied test material in the epidermis/dermis, it is uncertain whether the residue is within the living skin. We studied the dermal absorption of a hair dye hydroxyanthraquinone–aminopropyl methyl morpholinium methosulphate (HAM) in human skin in vivo and in vitro. In vivo, skin (back and scalp) received 0.5% HAM in a commercial formulation at 20 μg/cm² After 0.5 or 48 h, skin was tape stripped, followed by cyanoacrylate biopsies (CAB). Sebum from scalp sites was collected for 48 h. In vitro, skin was treated with 20 mg/cm² dye for 0.5 h, penetration determined after 24 h. In vivo, at 0.5 h, total recovery (back) was 0.67 μg/cm² (tape strips + CAB). Fluorescence microscopy showed HAM in the hair follicle openings (HFO). At 0.5 h, scalp tape strips contained 1.80 μg/cm², HFO 0.82 μg/cm². At 48 h, HFO contained 0.21 μg/cm², sebum 0.80 μg/cm². In vivo, skin residues were in the non-living skin and eliminated via desquamation and sebum secretion. In vitro, the SC contained 1.50 μg/cm², epidermis/dermis 0.86 μg/cm², receptor fluid < 0.04 μg/cm², a total of 0.90 μg/cm² was considered to be bioavailable. In vitro epidermis/dermis residues were nearly identical to those located in non-living skin in vivo. In conclusion, in vitro percutaneous penetration studies may produce seemingly bioavailable material , which raises the need for a Threshold of Skin Absorption (TSA) addressing a negligible dermal absorption in order to avoid unnecessary in vivo toxicity studies on substances that produce no significant human systemic exposure.