Inflammatory Enzyme Activities Research Articles

Quercetin alleviates hypercholesterolemic diet induced inflammation during progression and regression of atherosclerosis in rabbits

ObjectiveRecent advances have established a fundamental role for inflammation in mediating all stages of atherosclerosis, from initiation through progression. Quercetin may be a powerful bioactive constituent of the human diet, as a free radical scavenging agent and through interactions with various endogenous proteins. The present study focused on the effect of quercetin on inflammation induced by a hypercholesterolemic diet (HCD) in rabbits. MethodsThe animals were subjected to two different experiments, atherosclerotic progression and regression. In the atherosclerotic progression study, quercetin (25 mg/kg of body weight) was administered with the HCD for 90 d. In the atherosclerotic regression study, the animals were fed with the HCD for 90 d and then supplemented with quercetin (25 mg/kg of body weight) for another 90 d. The inflammatory enzyme activities were examined and a histopathologic examination of the aorta was performed. ResultsIn the atherosclerotic progression study, quercetin coadministered with the HCD significantly decreased the activities of inflammatory enzymes such as cyclooxygenase, lipoxygenases (LOX) such as 5-LOX and 12-LOX in monocytes, nitric oxide synthase activity in the plasma, myeloperoxidase activity in the aorta, and the level of C-reactive protein in serum. In the regression study, quercetin administration significantly decreased the increased activities of inflammatory mediators such as cyclooxygenase, 5-LOX, 12-LOX, myeloperoxidase, and nitric oxide synthase and the serum level of C-reactive protein in HCD-fed rabbits compared with regression control rabbits. This effect was confirmed by histopathologic examination of the aorta. ConclusionThis study demonstrates that quercetin modulates the deleterious inflammatory effects induced by an HCD in vivo in rabbits, suggesting its beneficial effect in decreasing inflammation in atherosclerotic progression and regression.

Sponge implant in Swiss mice as a model for studying loxoscelism

Envenomation by Loxosceles spider bite leads to a set of signs and symptoms, called loxoscelism, which in most cases manifests through the dermonecrotic frame. The development of a smaller size animal model, of easy handling and maintenance, and lower cost is needed to study the loxoscelism pathogenesis. The inflammatory effects of the Loxosceles similis crude venom was evaluated considering neutrophil and macrophage activation, vasodilatation, hyperhaemia, edema and hemorrhage and TNF-α and VEGF production using the murine sponge implant model. Thirty two male Swiss mice (6–8 weeks old) were implanted subcutaneously with polyether–polyurethane sponge discs. Fourteen days post implantation, animals were separated into two groups: (1) control group – 16 mice received 30μL of saline intra-implant; (2) treated group-sixteen mice injected with 0.5μg/30μL of L. similis crude venom intra-implant. The animals were euthanized with xylazine/ketamine after 1 and 4h post- injection. Microscopically, implants of the treated groups presented an acute inflammation characterized by: neutrophilic infiltrate, edema, vasodilatation hyperhaemia, and severe hemorrhage. Some vessels presented ruptured walls. Under morphometric analysis, vessel area was bigger in the treated groups compared with the control ones. The biochemical parameters, hemoglobin content, inflammatory enzyme activities (myeloperoxidase and n-acethyl-β-d glucosaminidase) and levels of the cytokines, TNF-α and VEGF, were also significantly higher in the venom-treated groups. The effects of Loxosceles venom in the granulation tissue of the implant in mice were similar to those observed in cutaneous loxoscelism in other species (human and rabbits). Consequently, the murine sponge implant model provides a new method to investigate cellular/molecular mechanisms associated with cutaneous loxoscelism.

Distinct Pattern of Inflammatory Enzyme Activities in Human Ovarian Cancer and Benign Myoma

Objective: Inflammatory cells and their products are significant components of malignancies. This study was performed to determine the activity of inflammatory enzymes myeloperoxidase (MPO) and N-acetylglucosaminidase (NAG) in ascitic fluid, sera or peritoneal lavage fluid from patients with epithelial ovarian cancer (EOC). Methods: Eighteen patients age ranging from 25 to 79 years (54.6±2.9 years) with epithelial ovarian cancer submitted to surgical treatment (EOC group) and 17 patients with uterine myoma (Myoma group) submitted to abdominal hysterectomy (control group) were prospectively studied. MPO and NAG activities were evaluated colorimetrically in sera, ascites or peritoneal lavage fluid obtained from the patients at the time of laparotomy. Results: In a total of 18 EOC, there were stage I in 1 case (5.5%), II in 3 (16.7%), III in 11 (61.1%) and IV in 3 cases (16.7%). MPO activity in sera of EOC was higher than in the ascitic fluid from the same patients. Conversely, MPO activity was similar in sera from both EOC and myoma-bearing patients. Comparison between NAG activities in sera from both groups showed much higher values in the OEC patients. Furthermore, inflammatory enzyme activities were overall associated with the stage of the disease. Conclusions: Our results show that inflammation has been positively correlated with cancer and that the pattern of a systemic inflammatory response induced by EOC differs quantitatively from that of a typical benign pelvic condition. The most important limitation lies in the fact that the number of patients and controls was relatively small. Further studies with a larger number of patients and longer follow-up are necessary to assess the accuracy of the diagnostic and prognostic impact of these results.

Anti-inflammatory and antioxidative effects of mucilage of Trigonella foenum graecum (Fenugreek) on adjuvant induced arthritic rats

The aim of this study was to investigate anti-inflammatory and antioxidant effects of mucilage from fenugreek in adjuvant induced arthritis in rats. Arthritis was induced by intradermal injection of complete Freund's adjuvant into the right hind paw produce inflammation of the joint. The activities of inflammatory enzymes like cyclooxygenase, lipoxygenase and myeloperoxidase, and levels of nitrite and C-reactive protein were observed. Also oxidative stress was measured by analyzing the activity of catalase, superoxide dismutase, glutathione peroxidase and the levels of glutathione and vitamin C and lipid peroxidation. The blood parameters like ESR, total WBC, RBC and hemoglobin content was checked. Fenugreek mucilage exhibited maximum percentage of edema inhibition at a dose of 75 mg/kg on 21st day of adjuvant arthritis. The effect was higher than that of standard drug indomethacin. The activities of cyclooxygenase-2 and myeloperoxidase and concentration of thiobarbituric acid reactive substance (TBARS) were decreased and the activities of antioxidant enzymes, vitamins C and reduced glutathione level were increased on treatment with fenugreek mucilage. The increment in ESR and total WBC, reduction in RBC count and hemoglobin and aberrant changes to the C-reactive protein (CRP) levels observed in the arthritic animals were also found to be significantly restored in fenugreek mucilage treated rats. Histopathology of paw tissue showed decreased edema formation and cellular infiltration on supplementation with fenugreek mucilage. Thus the results demonstrated the potential beneficiary effect of fenugreek mucilage on adjuvant induced arthritis in rats.

Quercetin regulates oxidized LDL induced inflammatory changes in human PBMCs by modulating the TLR-NF-κB signaling pathway

Toll-like receptors (TLRs) have been shown to play a pivotal role in both innate and adaptive immune responses. TLR family is the essential recognition and signaling component of mammalian host defense. Both genetic and biochemical data support a common signaling pathway that finally leads to the activation of NF-κB and induction of the cytokines and co-stimulatory molecules required for the activation of the adaptive immune response. The present study was designed to examine the involvement of TLR2 and TLR4 in the oxidized LDL induced inflammation in human PBMCs and the effect of flavonoid quercetin on TLR-NF-κB signaling mechanism. LDL was isolated from human plasma and oxidation of LDL was done by incubating with 10 μM CuSO 4 overnight at 37 °C. The isolated human PBMCs in culture were used as the model system. 50 μg/ml ox-LDL treatment significantly up regulated TLR2 and TLR4 expression in isol human PBMCs after 24 h of culture and this was down regulated by quercetin at 25 μM concentration. ox-LDL caused a significant activation of NF-κB as evidenced by the detection of enhanced p65 subunit in nuclear extracts. Supplementation of quercetin significantly modulates the NF-κB p65 nuclear translocation. The cytokine IL-6 production was significantly increased in ox-LDL treated group and was decreased by quercetin treatment. Quercetin mediated reduction of TLR2 and TLR4 expression and the inhibition of nuclear translocation of NF-κB p65 in turn decreased the inflammatory enzymes like 5-LOX and COX and also decreased the mRNA expression of inducible enzymes like COX-2 and iNOS. Quercetin inhibited the ox-LDL induced TLR2 and TLR4 expression at mRNA level and modulated the TLR-NF-κB signaling pathway thereby inhibited the cytokine production and down regulated the activity of inflammatory enzymes thus have protective effect against the ox-LDL induced inflammation in PBMCs.

N-Methyl-d-aspartate receptor antagonism decreases motility and inflammatory activation in the early phase of acute experimental colitis in the rat

Inflammatory bowel diseases are accompanied by severe motility disorders. The aim of our study was to investigate whether the blockade of peripheral N-methyl-D-aspartate (NMDA)-sensitive glutamate receptors (NMDA-Rs) alters motility changes in chemically induced acute colitis and how this modulation is accomplished. The inflammatory and motility changes in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis were studied in anaesthetized Wistar rats following treatment with the natural NMDA-R antagonist kynurenic acid (KynA) or SZR-72, a blood-brain barrier-permeable synthetic KynA analogue. The macrohaemodynamics, serosal microcirculation (visualized by intravital videomicroscopy), plasma levels of tumour necrosis factor alpha (TNF-alpha), inflammatory enzyme activities (xanthine oxidoreductase (XOR), myeloperoxidase (MPO) and nitric oxide synthase (NOS)), and colonic motility (with a strain-gauge technique) were evaluated 17 h after colitis induction and compared with the control conditions. The TNBS enema induced a systemic hyperdynamic circulatory reaction, increased the serosal capillary blood flow, significantly elevated the mucosal XOR, MPO and NOS activities and augmented the colonic motility relative to the controls. The NMDA-R antagonist treatment with KynA or SZR-72 significantly reduced the XOR, NOS and MPO activities, decreased the motility and increased the tone of the colon. These data demonstrate a potential modulatory mechanism of NMDA-R in altered colonic motility in TNBS colitis. Inhibition of the enteric NMDA-Rs may provide a therapeutic option via which to influence intestinal hypermotility, microcirculatory changes and inflammatory activation simultaneously.

Effect of Nonsteroidal Anti-Inflammatory Drugs on the Cellular Membrane Fluidity

In this work, fluorescence measurements were performed using the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH) to evaluate the effects of the interaction of nonsteroidal anti-inflammatory drugs--NSAIDs (meloxicam, lornoxicam, and nimesulide) with several membrane systems (liposomes with and without cholesterol, mouse splenocytes, mouse macrophages cell line--J774, human leukemia monocyte cell line--THP-1, and human granulocytes and mononuclear cells). DPH fluorescence quenching studies revealed that the NSAIDs studied were able to efficiently quench the probe located in membrane hydrocarbon region. Fluorescence anisotropy measurements were also made to investigate the effects on membrane fluidity resulting from the interaction between the drugs and membrane systems. All the anti-inflammatory drugs studied show an increase in the membrane fluidity in a concentration dependent manner. Results obtained provide an insight into NSAIDs capacity to be inserted in lipid bilayers and alter the lipid dynamics. The induced changes in lipid dynamics may modulate the activity of inflammatory enzymes or may be related with deleterious topical action of NSAIDs on gastric phospholipid fluidity.

Molecular mechanisms of calorie restriction's protection against age-related sclerosis

The current knowledge on the molecular mechanisms of the protective effect of calorie restriction (CR) against age-related fibrosclerosis is tentatively reviewed with specific reference to the role of oxidative stress in aging. The effects of oxidative stress are often mediated by its own final products. Of these, 4-hydroxy-2,3-nonenal (HNE) induces the expression and synthesis of transforming growth factor beta1 (TGFbeta1) and activates nuclear binding of transcription factor activator protein 1 (AP-1) thus stimulating fibrogenesis. Several studies have shown that, as well as extending mean and maximum life span in a variety of species, CR delays the onset and slows the progression of a variety of age-associated diseases, including diabetes, cardiovascular diseases and neoplasia. However, the anti-aging mechanisms of CR are still not clearly understood. Of the numerous hypotheses put forward, one that still remains popular is protection against the age-associated increase of oxidative stress and consequent cell damage. CR protects the rat aorta from the age-related increase of both oxidative damage and fibrosis; as regards the possible mechanism/s of CR's protection against fibrosclerosis, it is conceivable that, by decreasing oxidative stress, CR reduces HNE levels and consequently TGFbeta1 expression and collagen deposition, likely by down-regulating the activation of Jun-N terminal kinase and of AP-1. Through the modulation of reactive oxygen species and oxidative stress CR may also attenuate the age-associated increase in the inflammatory milieu, thus preserving vascular functional integrity by suppressing the age-associated increase in inflammatory enzyme activities and prostanoids.