油橄榄叶醇提取物对D-半乳糖胺/脂多糖致小鼠急性肝损伤的保护作用及其作用机制

研究油橄榄叶醇提取物(OLME)对D-半乳糖胺/脂多糖诱导小鼠肝损伤的保护作用。昆明种小鼠按体质量随机分为6组,即空白对照组、模型对照组、阳性对照组(联苯双酯200 mg/kg·d)、OLME低、中、高剂量组(200、400、800 mg/kg·d)。每天给药1次,连续给药14 d,末次给药1 h后,除正常组外其余各组用600 mg/kg·BW D-半乳糖胺和40 μg·kg^-1脂多糖腹腔注射以复制小鼠急性肝损伤模型,末次给药12 h后,摘眼球取血,取材。用生化法测定小鼠血清中谷氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)活性,用试剂盒测定各组小鼠肝匀浆中超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性、丙二醛(MDA)含量、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)和白细胞介素-6(IL-6)等炎性因子的表达水平以及半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)和半胱氨酸天冬氨酸蛋白酶-8(Caspase-8)活性。与模型组比较,OLME中高剂量组小鼠血清中ALT和AST活力显著降低(p<0.05),肝组织中MDA、TNF-α、IL-1β和IL-6含量显著降低而SOD活力显著升高(p<0.05),但OLME对GSH-Px改善作用不明显,仅OLME高剂量有一定效果;OLME低、中、高剂量均能显著降低caspase-3和caspase-8活性(p<0.05)。OLME对D-半乳糖胺/脂多糖诱导的小鼠急性肝损伤具有较好的保护作用。     

Mechanisms involved in milk endogenous proteolysis induced by a lipopolysaccharide experimental mastitis

Experimental mastitis has been induced by the lipopolysaccharide (LPS) of Escherichia coli on six dairy cows in order to study the mechanisms involved in milk endogenous proteolysis during the inflammatory process. Variations in somatic cell count (SCC), plasmin activity, and total casein (CN) content were measured, and proteose-peptone content and the percentage of pH 4.6 insoluble peptides including gamma-CN have been considered as indicators of endogenous proteolysis. Furthermore, polymorphonuclear neutrophils (PMN) maturity has been evaluated by optical microscopy, and proteolysis by PMN proteinases has been studied at neutral and acidic pH in order to establish a link between caseinolysis, proteinase class, and PMN maturation. Two peaks of proteose-peptones content have been noticed for the six cows. First peak could be explained by both plasmin activity and SCC, while second peak was concomitant with a low plasmin activity but a SCC remaining high. The second peak of proteose-peptones content confirmed the role of cellular proteases in milk caseinolysis. Casein breakdown by cellular proteases was confirmed by SDS-PAGE electrophoresis, and a link between neutral proteinases activity and immature PMN recruitment was shown. Acidic proteinases activity was effective with mature PMN and during the recovery phase.     

富锌牡蛎粉对小鼠酒精性肝损伤的保护作用

研究富锌牡蛎粉对小鼠酒精肝损伤的保护作用。实验各组小鼠灌胃相应实验样品,检测小鼠血清中天门冬氨酸转氨酶（Aspartate transaminase,AST）、丙氨酸氨基转移酶（Alanine aminotransferase,ALT）和谷氨酰转移酶（GGT）活性,肝组织匀浆液中谷胱甘肽过氧化物酶（Glutathione peroxidase,GSH-Px）、超氧化物歧化酶（Superoxide Dismutase,SOD）和过氧化氢酶（Hydrogen Peroxidase,CAT）的活性及丙二醛（Malondialdehyde,MDA）的含量,并观察肝组织在光镜下病理变化。结果表明富锌牡蛎粉可以显著降低酒精致肝损伤小鼠血清中AST、ALT和GGT的活性（p<0.05）,增强小鼠肝组织匀浆液中GSH-Px、SOD和CAT活性（p<0.05）,显著降低MDA含量（p<0.05）,并明显改善乙醇导致的肝脏组织病理学变化。以上结果表明,富锌牡蛎粉对酒精致小鼠肝损伤具有一定的保护作用,可能与其增强机体抗氧化能力和抑制脂质氧化有关。      

Effect of coffee melanoidin on human hepatoma HepG2 cells. Protection against oxidative stress induced by tert-butylhydroperoxide

Soluble high-molecular weight fraction (named melanoidin) from coffee brew was isolated by ultrafiltration, subsequently digested by simulating a gastric plus pancreatic digestive condition and partly characterized by CZE, gel-filtration and browning. The objective of the present study was to investigate the potential protective effect of the coffee melanoidin submitted to gastrointestinal digestion on cell viability (lactate dehydrogenase leakage) and redox status of cultured human hepatoma HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of antioxidant enzymes glutathione peroxidase (GPx) and reductase (GR) were used as markers of cellular oxidative status. Pretreatment of cultured HepG2 cells with 0.5-10 microg/mL digested coffee melanoidin (DCM) for 2 or 20 h completely prevented the increase in cell damage and GR and partly prevented the decrease of GSH and the increase of MDA and GPx evoked by t-BOOH in HepG2 cells. In contrast, increased ROS generation induced by t-BOOH was not prevented when cells were pretreated with DCM. The results show that treatment of HepG2 cells with concentrations of DCM within the expected physiological range confers the cells a significant protection against an oxidative insult.     

Relief effects of Laoshan cherry extracts as a dietary supplement against the symptoms of acute gouty arthritis in rats induced by urate crystals

We evaluated the effects of Laoshan cherry as a food or dietary supplement on relieving the symptoms of acute gouty arthritis in rats induced by urate crystals. Rats in groups of 10 were given Laoshan cherry functional extracts at doses of 5, 10, and 20 mg/kg by oral gavage for 21 days and then injected with a sodium nitrate suspension in the rear ankle area as an induced acute gouty arthritis model. The ankle swelling and inflammations in the model (no treatment) group increased significantly compared with blank group; the ankle inflammations reduced in experimental groups receiving three different doses of the cherry extract and the joint swelling reduced in the high-dose group by 43% compared with the model group. Serum uric acid and xanthine oxidase activities were also elevated in the model group and these parameters were reduced by a maximum of 8% and 33%, respectively, in the rats receiving the cherry extracts. The serum levels of the inflammatory cytokine IL-1β in the high-dose group decreased by 12% compared with the model group. These results demonstrated that the cherries possess a functional substance that has a significant alleviating effect on the symptoms of gouty arthritis in rats induced by sodium urate injection.     

Treatment with Bifidobacterium bifidum 17 partially protects mice from Th1-driven inflammation in a chemically induced model of colitis

Probiotics have been suggested as an alternative therapeutical approach in the intervention of inflammatory disorders of the gastrointestinal tract (GIT). Application of single strains or probiotic mixtures has shown promising results in animal models and patients of inflammatory bowel disease (IBD). We recently demonstrated potent inhibitory capacity of a Bifidobacterium bifidum S17 on LPS-induced inflammatory events in cell culture models using intestinal epithelial cells and verified these anti-inflammatory effects in two mouse models of colitis. In the present study we analyze the anti-inflammatory effect of this potential probiotic strain in a chemically-induced model of colitis in C57BL/6 mice. This model is characterized by a strong type 1T helper (Th1) response resembling Crohn's disease, one of the two most prevalent forms of IBD. We performed macroscopic analysis and determined the effect of B. bifidum S17 on the cytokine balance in biopsies of the colonic mucosa. While treatment with B. bifidum S17 only had a marginal effect on weight loss, no difference was observed in the macroscopic parameters. However, a significant reduction in histology scores and the levels of pro-inflammatory cytokines interleukin 1β (IL-1β), interleukin 6 (IL-6), keratinocyte-derived chemokine (KC) and the inflammatory markers cyclooxigenase 2 (Cox-2) and myeloperoxidase (MPO) was observed. These results indicate that treatment with B. bifidum S17 is able to partially inhibit the strong Th1-driven intestinal inflammation induced in our model of colitis.     

Therapeutic effect of ginsenoside Rg1 on mastitis experimentally induced by lipopolysaccharide in lactating goats

Escherichia coli is a cause of subclinical and clinical mastitis in dairy cattle and goats, and sometimes causes severe clinical disease that may result in death of the animal. Previous investigation showed that ginsenoside Rg1 extracted from Panax ginseng C.A. Meyer (Araliaceae) has an anti-inflammatory effect on the sepsis induced by E. coli lipopolysaccharide via competitive binding to toll-like receptor 4. We hypothesized that intravenous injection of Rg1 had therapeutic effect on mastitis experimentally induced by intramammary infusion of lipopolysaccharide in lactating goats. In this study, 9 lactating goats were randomly assigned to 1 of the 3 groups: (1) lipopolysaccharide intramammary infusion + saline intravenous injection, (2) lipopolysaccharide intramammary infusion + Rg1 intravenous injection, and (3) saline intramammary administration + saline intravenous injection. Because no adverse clinical signs were observed after intramammary infusion of saline and intravenous injection of Rg1 in a preliminary experiment, and available qualified goats were limited in this study, this treatment was not included in this study. One udder half of each goat received intramammary infusion of lipopolysaccharide (50 μg/kg of body weight; groups 1 and 2) or saline solution (group 3), and the other half was infused with 2 mL of saline solution at h 0. Afterward, intravenous injections of saline solution (groups 1 and 3) or Rg1 (2.5 mg/kg of body weight; group 2) were administered at h 2 and 4 post-lipopolysaccharide challenge. Blood and milk samples were collected 3, 6, 9, 12, 15, 18, 21, 24, 48, and 72 h post-lipopolysaccharide challenge, and clinical signs were monitored hourly after lipopolysaccharide challenge within the first 10 h and at the same time points as blood samples. The results showed that Rg1 treatment downregulated rectal temperature, udder skin temperature, udder girth, milk somatic cell count, and N-acetyl-β-d-glucosaminidase and upregulated milk production, lactose, and recovered blood components, such as white blood cells, neutrophils, lymphocytes, total proteins, albumin, and globulin. Considering the positive therapeutic effect on lipopolysaccharide-induced mastitis in goats presented in this study as well as the anti-inflammatory activity found previously, the botanical Rg1 deserves further study as a therapeutic agent in the treatment of E. coli mastitis in dairy animals.     

rhAPC reduces the endothelial cell permeability via a decrease of contractile tensions induced by endothelial cells

All cells generate contractile tension. This strain is crucial for mechanically controlling the cell shape, function and survival. In this study, the CellDrum technology quantifying cell's (the cellular) mechanical tension on a pico-scale was used to investigate the effect of lipopolysaccharide (LPS) on human aortic endothelial cell (HAoEC) tension. The LPS effect during gram-negative sepsis on endothelial cells is cell contraction causing endothelium permeability increase. The aim was to finding out whether recombinant activated protein C (rhAPC) would reverse the endothelial cell response in an in-vitro sepsis model. In this study, the established in-vitro sepsis model was confirmed by interleukin 6 (IL-6) levels at the proteomic and genomic levels by ELISA, real time-PCR and reactive oxygen species (ROS) activation by florescence staining. The thrombin cellular contraction effect on endothelial cells was used as a positive control when the CellDrum technology was applied. Additionally, the Ras homolog gene family, member A (RhoA) mRNA expression level was checked by real time-PCR to support contractile tension results. According to contractile tension results, the mechanical predominance of actin stress fibers was a reason of the increased endothelial contractile tension leading to enhanced endothelium contractility and thus permeability enhancement. The originality of this data supports firstly the basic measurement principles of the CellDrum technology and secondly that rhAPC has a beneficial effect on sepsis influenced cellular tension. The technology presented here is promising for future high-throughput cellular tension analysis that will help identify pathological contractile tension responses of cells and prove further cell in-vitro models.     

The In Vitro permeability of yeast peroxisomal membranes is caused by a 31 kDa integral membrane protein

A major 31 kDa integral peroxisomal membrane protein (PMP31) of Hansenula polymorpha was purified to homogeneity from isolated peroxisomal membranes by FPLC after solubilization by Triton X-100. Biochemical analysis indicated that this protein, which showed cross-reactivity with antibodies against the 31 kDa porin of the mitochondrial outer membrane of Saccharomyces cerevisiae, had pore-forming properties. Firstly, proteoliposomes composed of asolectin and purified PMP31 showed selective permeability, determined as the [¹⁴C]sucrose/[³H]dextran leakage ratios. Furthermore, the generation of a ΔΨ by potassium diffusion gradients was negatively affected by the presence of PMP31 in asolectin liposomes. A similar effect was observed in proteoliposomes containing purified cytochrome c oxidase as a ΔΨ generating system. Control experiments confirmed that the observed leakage is significant and introduced by the incorporation of PMP31 protein. Selective sucrose leakage was abolished in samples pretreated with glutaraldehyde; an identical effect of glutaraldehyde was, however, not observed for the membrane potential measurements.     

Protection of ovalbumin against irreversible heat denaturation by a cationic amphiphile at high concentration

The interaction of the cationic amphiphile cetylpyridinium chloride (CPC) with the egg white protein ovalbumin, was studied at various temperatures and pH values. The influence of different concentrations of CPC on the thermal behaviour of the protein was followed by specific optical rotation measurements in the pH interval 3-9. No increase in optical rotation was found at any pH when CPC was added to ovalbumin at room temperature. When heated, a gradual increase in optical rotation was registered, which became smaller the higher the pH used. At molar ratios of CPC :ovalbumin of above 70 this increase was reversed on cooling. The reversibility of the thermal unfolding on cooling was not affected by a variation in protein concentration between 0.5 and 10%. Circular dichroism measurements before and after a heating-cooling cycle confirmed the results obtained on optical rotation. When CPC was exchanged against the anionic amphiphile, sodium dodecylsulphate (SDS), a denaturing effect was achieved at neutral and alkaline pH values already at room temperature. At the acidic side of the isoelectric point, however, there was no major effect of SDS. No thermal aggregation of ovalbumin occurred near the isoelectric point when CPC was present and complete resolubility was found after thermal treatment and drying.     

Efficacy of a typical clean-in-place protocol against in vitro membrane biofilms

This study evaluates the effectiveness of a typical clean-in-place (CIP) protocol against in vitro biofilms on whey reverse osmosis (RO) membranes developed under static condition. Bacterial isolates obtained from RO membrane biofilms were used to develop single and multispecies biofilms under laboratory conditions. A typical commercial CIP protocol was tested against the 24-h-old biofilms, and included 6 sequential treatment steps based on alkali, surfactant, acid, enzyme, a second surfactant, and a sanitizer treatment step. Experiments were conducted in 4 replicates and the data were statistically analyzed. The results revealed a variation in the resistance of mixed-species biofilms against the individual steps in the sequential CIP protocol. The overall 6 steps protocol, although resulted in a greater reduction, also resulted in the detection of survivors even after the final sanitizer step, reflect the ineffectiveness of the CIP protocol for complete removal of biofilms. Posttreatment counts of 0.71 log after the sequential CIP of mixed-species biofilm revealed the resistance of biofilm constitutive microbiota. Mixed-species biofilms, constituting different genera including Bacillus, Staphylococcus, and Streptococcus, were observed to be more resistant than most of the single-species biofilms. However, among the single-species biofilms, significantly different resistance pattern was observed for Bacillus isolates compared with the other bacterial isolates. All 5 isolates of Bacillus were found resistant with survivor counts of more than 1.0 log against the sequential CIP protocol tested. Thus, it can be concluded that the tested CIP protocol had a limited effectiveness to clean membrane biofilms formed on the whey RO membranes.     

Protective effects of a synthetic soybean isoflavone against oxidative damage in chick skeletal muscle cells

The antioxidant and protective properties of a synthetic soybean isoflavone (SI) were investigated using chick skeletal (leg) muscle cells (SMC) isolated from 20-day-old Linnan yellow broiler chick embryo. Skeletal muscle cells were cultured in Dulbecco’s modified Eagle’s medium treated with 0, 12.5, 25, 50, 75 and 100 μM SI, respectively, under 80 μM H₂O₂/FeSO₄ conditions. After 24 h of incubation, SI reduced the loss of SMC under oxidative stress by H₂O₂/FeSO₄. The addition of SI significantly promoted SMC proliferation (P < 0.01). Upon treatment with 25, 50, 75 and 100 μM SI, the activity of total superoxide dismutase in the supernatant of the media was enhanced by 17.0%, 13.0%, 13.3% and 11.9%, respectively (P < 0.05). Compared to the control, the activity of glutathione peroxidase was significantly increased only at 25 μM concentration of SI (P < 0.05), and the increment was 90.7%. The activity of catalase was increased by 49.2% and 49.1%, respectively, at 75 and 100 μM SI (P < 0.01). The concentration of creatine kinase in the media was decreased by 61.6% and 60.6%, respectively, at 75 and 100 μM SI (P < 0.01). The addition of SI did not affect the activity of lactate dehydrogenase in the media. In conclusion, the SI protected skeletal muscle cells from oxidative damage, attributed to its antioxidant activity.     

药食两用植物改善饮食诱导代谢性炎症研究进展

代谢性炎症具有缓慢性、隐匿性、持续性、关联性等特点,未加及时防治可能破坏机体稳态,导致代谢紊乱并且干扰能量平衡,继而引发肥胖、代谢综合征、代谢相关脂肪性肝病、动脉粥样硬化、2型糖尿病等难治病症。伴随着人类生活方式和饮食结构的改变,肥胖等慢性代谢性疾病已成为世界公共卫生健康备受关注的焦点,代谢性炎症作为这些疾病发病机制的启动因素,通过阻断其发生发展已成为代谢性疾病的重要防治策略。目前研究发现多种药食两用植物表现出良好的抗炎作用,其具有安全、稳定、易接受、毒副作用小及无耐药性等优势。本文通过从药食两用植物目录中筛选发挥缓解炎症、调节代谢等作用的植物及其有效成分,归纳总结改善饮食诱导代谢性疾病的相关作用机制,以期为深入研究代谢性疾病的预防和治疗提供参考。     

冷压初榨椰子油对四氯化碳致小鼠 急性肝损伤的保护作用

研究了冷压初榨椰子油对四氯化碳（CCl4）诱导昆明小鼠急性肝损伤的保护作用。将72只昆明小鼠随机分成6组,包括正常组、四氯化碳肝损伤模型组、联苯双酯组（150 mg/kg）、椰子油低剂量组（5 mL/kg）、椰子油中剂量组（10 mL/kg）、椰子油高剂量组（20 mL/kg）,通过测定小鼠血清中丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）、乳酸脱氢酶（LDH）、甘油三酯（TG）和总胆固醇（TC）指标,肝组织中超氧化物歧化酶（SOD）活力、谷胱甘肽过氧化物酶（GSH-Px）活力及丙二醛（MDA）含量,采用HE染色切片对小鼠肝脏组织进行病理学检查,考察冷压初榨椰子油对四氯化碳致小鼠急性肝损伤的保护作用。结果表明：与模型组相比,不同剂量组的冷压初榨椰子油（5、10 mL/kg和20 mL/kg）可以不同程度地降低小鼠血清中ALT、AST、LDH、TG、TC水平以及肝组织中MDA含量,提高肝组织中SOD活力与GSH-Px活力;同时,肝脏组织病理学观察与生化指标检测结果一致。其中,高剂量的冷压初榨椰子油(20 mL/kg)作用效果优于阳性对照联苯双酯。研究表明冷压初榨椰子油对肝脏具有较好的保护作用,作用机制可能与其含有较多的抗氧化物质以及功能性物质有关。     

Ginger attenuates inflammation in a mouse model of dextran sulfate sodium-induced colitis

Food Science and Biotechnology - This study assessed the anti-inflammatory effect of ginger extract on colitis by 5% dextran sulfate sodium (DSS) in BALB/c mice. The mice were administered either...     

Yoghurt consumption regulates the immune cells implicated in acute intestinal inflammation and prevents the recurrence of the inflammatory process in a mouse model

Crohn's disease and ulcerative colitis, two forms of inflammatory bowel disease, are important problems in industrialized countries. The complete etiology of these two diseases is still unknown but likely involves genetic, environmental, and immunological factors. The aim of the present work was to determine whether the anti-inflammatory effects reported for yoghurt in acute trinitrobenzene sulfonic acid-induced intestinal inflammation in mice also could prevent or attenuate the recurrent intestinal inflammation, thus maintaining remission. The innate response also was evaluated through participation of Toll-like receptors (TLRs) and the analysis of T-cell populations to determine the effects of yoghurt in an acute inflammatory bowel disease model. Yoghurt exerted a beneficial effect on acute intestinal inflammation by regulating T-cell expansion and modulating the expression of TLRs, with decrease of TLR4(+) and increase of TLR9(+) cells. The anti-inflammatory effect of yoghurt also was demonstrated in a recurrent inflammation model. Yoghurt administration during the remission phase prevented the recurrence of inflammation without producing undesirable side effects. The yoghurt effect may be mediated by increased interleukin 10 production and changes in intestinal microbiota.