Protective Effect of Curcumin on Endotoxin-induced Acute Lung Injury in Rats

Acute lung injury (ALI) or its more severe form, the acute respiratory distress syndrome (ARDS), is a common, devastating clinical syndrome that affects both medical and surgical patients. The most common cause of ALI is sepsis. There is now well-documented evidence that pulmonary inflammation contributes to the devel-opment of ALI. Despite significant advances in our un-derstanding of pathophysiology and technologies in the supportive management, mortality from ALI remains excessive. C…     

板蓝根中邻氨基苯甲酸的抗内毒素作用

目的研究板蓝根中邻氨基苯甲酸(o-aminobenzoic acid,OABA)的抗内毒素作用.方法将邻氨基苯甲酸配成0.5%水溶液,鲎试验法进行抗内毒素定量测定;内毒素致家兔发热实验检测邻氨基苯甲酸体内抗内毒素作用;脂多糖(LPS)致小鼠死亡试验测定邻氨基苯甲酸保护作用及邻氨基苯甲酸对脂多糖致小鼠过度释放肿瘤坏死因子-α(TNF-α)和一氧化氮(NO)的影响试验,研究邻氨基苯甲酸的抗内毒素作用.结果 0.833 mg·mL-1邻氨基苯甲酸可使4 EU内毒素降解为0.668 EU,破坏率为84.4%;0.5%邻氨基苯甲酸溶液可使内毒素引起的家兔体温升高显著降低,使同等剂量脂多糖引起的小鼠死亡率从70%降为20%;板蓝根中的邻氨基苯甲酸可抑制脂多糖致小鼠血清中TNF-α和NO的过度释放,其抑制率呈剂量依赖性.结论从板蓝根中分离出的邻氨基苯甲酸有抗内毒素作用.     

柴芍承气汤对脂多糖诱发的小鼠肠套叠的预防及还纳作用

目的利用脂多糖小鼠肠套叠动物模型观察柴芍承气汤对肠套叠的预防及还纳作用。方法小鼠腹腔内注射脂多糖(1ipopolysaccharide,LPS,12mg/kg)诱发肠套叠模型。小鼠每30只分为1组,分别在LPS注射前或诱发肠套叠后给予柴芍承气汤灌胃(0．4ml/10g体重),观察其对肠套叠诱发率、肠套叠还纳率及胃肠传递时间的影响。结果LPS的肠套叠诱发率在第6h为26．7%,第9h为23．3%。注射LPS前1h预防性给予柴芍承气汤,肠套叠诱发率为零,传递指数(TI)为52．3%,而未给予柴芍承气汤组,TI为37．7%,正常对照组TI为56．2%。在注射LPS后第6h服用柴芍承气汤,使第9h的肠套叠率下降至3．3%。结论柴芍承气汤有预防和治疗LPS相关肠套叠的作用。     

n,n′-二乙酰-L-胱氨酸对半乳糖胺联用脂多糖引起小鼠免疫性肝衰竭的作用

目的研究n,n′-二乙酰-L-胱氨酸(DiNAC)对免疫性肝衰竭的治疗作用。方法观察DiNAC对Balb/C小鼠由半乳糖胺联用脂多糖引起免疫性肝衰竭的作用。半乳糖胺/脂多糖攻击6 h后，小鼠血清ALT，AST和外周血T细胞亚群分别用全自动生化仪、流式细胞仪测定，并用光镜观察肝组织病理切片，统计半乳糖胺/脂多糖攻击24 h后的小鼠存活率。结果给肝衰竭小鼠ip DiNAC(50，200，800 mg·kg^-1)，能明显阻止小鼠血清ALT和AST活力增高，使肝组织损害减轻及提高小鼠存活率，并呈剂量依赖关系；DiNAC能增强免疫性肝衰竭小鼠外周血CD4⁺,CD8⁺,Th1和Th2 T淋巴细胞的增殖分化。结论DiNAC对免疫性肝衰竭动物有明显的治疗作用，这一作用与其免疫调节有关。     

Pretreatment with lipopolysaccharide ameliorates Pseudomonas exotoxin A-induced hepatotoxicity in rats

Abstract

Context: Liver injury can be induced by various hepatotoxicants, including Pseudomonas aeruginosa exotoxin A (PEA). Our previous study indicated that PEA-induced rat hepatotoxicity was T cells and Kupffer cells dependent. Several reports have demonstrated that non-toxic doses of bacterial lipopolysaccharide (LPS) can protect liver against the chemicals-induced toxicity such as acetaminophen and concanavalin-A.

Objective: This study aimed to investigate the protecting mechanisms of LPS on PEA-induced hepatotoxicity.

Results: Rats pretreated with LPS (40?μg/kg, 12?h before PEA admission) significantly decreased animal mortality, serum enzyme (ALT, AST and T-bil) activities, histopathological changes and hepatocytes apoptosis following challenge with PEA. The concentrations of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and interleukin-2 (IL-2) were reduced, but IL-6 and IL-10 were increased in the serum. In addition, prior treatment of these LPS-pretreated rats with gadolinium chloride (GdCl₃), a selective Kupffer cell depletion agent, markedly enhanced liver injury after PEA administration. In contrast, the pretreatment of LPS to T-cell deficient athymic nude rats still display significant attenuation of PEA-induced liver injury. This observation further confirmed our hypothesis that LPS ameliorate PEA-hepatotoxicity was through Kupffer cells but not T cells. Moreover, LPS-induced hepatoprotection ability was neutralized by co-treatment with anti-TNF-α antibodies, but not with anti-IFN-γ antibodies. Finally, replacement of LPS with RS-LPS (Rhodobacter sphaeroides LPS), a Toll like receptor-4 (TLR-4) antagonist, resulted in severe hepatotoxicity.

Conclusion: These results suggested that Kupffer cells, TNF-α and TLR-4 play central mediator roles during the hepatoprotection against PEA-induced hepatotoxicity conferred by LPS.     

Immunomodulation of dendritic cells differentiated in the presence of nicotine with lipopolysaccharide from Porphyromonas gingivalis

Tobacco smoking is a significant risk factor for periodontal diseases. Nicotine, one of the most studied constituents in cigarette smoke, is thought to modify immune responses. Dendritic cells (DCs), which are key mediators between innate and adaptive immunity, stimulate naive T cells to differentiate to effector T‐cell subsets that may be actively involved in the immunopathogenesis of periodontal diseases. In this study, we evaluated the effects of nicotine and lipopolysaccharide (LPS) from Porphyromonas gingivalis, alone and in combination, on the functions of human monocyte‐derived DCs to elucidate the mechanism of tissue destruction of smoking‐associated periodontal diseases. P. gingivalis LPS‐stimulated DCs differentiated with nicotine (NiDCs) induced lower T‐cell proliferation and human leukocyte antigen (HLA)‐DR expression, but elevated expression of programmed cell death ligand 1. Additionally, NiDCs impaired interferon‐γ production but maintained interleukin (IL)‐5 and IL‐10 production in co‐cultured T cells. Furthermore, NiDCs produced lower levels of proinflammatory cytokines compared with DCs differentiated in the absence of nicotine. Interestingly, NiDCs preferentially produced the T helper 2 (Th2)‐type chemokines macrophage chemotactic protein‐1 and macrophage‐derived chemokine. These results suggest that the presence of nicotine during differentiation of DCs modulates the immunoregulatory functions of P. gingivalis LPS‐stimulated DCs.     

Bacteria-induced or bacterial product-induced preterm parturition in mice and rabbits is preceded by a significant fall in serum progesterone concentrations

Bacterial products are thought to induce labor by stimulating the production of pro-inflammatory cytokines and prostaglandins in gestational tissues, leading to the onset of preterm parturition. Progesterone withdrawal is a prerequisite of parturition in many species. Yet a role for progesterone in the mechanisms responsible for preterm parturition, in the setting of infection, is unclear. The current studies were conducted to determine if a fall in serum progesterone concentrations occurs before the onset of bacterial product-induced preterm parturition in animals.

Accordingly, pregnant mice at day 15 (70% gestation) were injected i.p. with Escherichia coli lipopolysaccharide (LPS; 50 μg/mouse) and timed-pregnant rabbits were inoculated transcervically with a suspension of E. coli to cause an ascending intrauterine infection. Control animals in both groups received equal volumes of sterile phosphate-buffered saline (PBS) solution. Blood specimens were collected at regular intervals and serum progesterone levels were determined by RIA. Within 14 h of LPS administration, mice delivered their pups. The median concentrations of serum progesterone were significantly lower at 1 h, 4 h, 10 h, and at the onset of preterm parturition (11–12 h) after LPS injection, compared to that in animals given PBS. Similarly, E. coli-inoculated rabbits delivered 1–2 days posttranscervical inoculation and demonstrated 60% decrease in serum progesterone within 12–24 h of inoculation compared to those given PBS. Parturition in both control groups occurred at term, following typical progesterone withdrawal. It is concluded that LPS administration to pregnant mice and ascending intrauterine infection in pregnant rabbits is associated with a dramatic fall in serum progesterone concentrations prior to the onset of parturition.     

Human apolipoprotein A-I Gly26Arg stimulation of inflammatory responses via NF-kB activation: Potential roles in amyloidosis?

The cascade of molecular events leading to Human apolipoprotein A–I (apoA–I) amyloidosis is not completely understood, not even the pathways that determine clinical manifestations associated to systemic protein deposition in organs such as liver, kidney and heart. About twenty natural variants of apoA–I were described as inducing amyloidosis, but the mechanisms driving their aggregation and deposition are still unclear. We previously identified that the mutant Gly26Arg but not Lys107-0 induced the release of cytokines and reactive oxygen species from cultured RAW 264.7 murine macrophages, suggesting that part of the pathogenic pathway could elicit of an inflammatory signal. In this work we gained deep insight into this mechanism and determined that Gly26Arg induced a specific pro-inflammatory cascade involving activation of NF-κB and its translocation into the nucleus. These findings suggest that some but not all apoA–I natural variants might promote a pro-oxidant microenvironment which could in turn result in oxidative processing of the variants into a misfolded conformation.