Anti-inflammatory effect of amurensin H on asthma-like reaction induced by allergen in sensitized mice.

AIM: To explore the anti-inflammatory effects of amurensin H on asthma-like reaction induced by allergen in sensitized mice. METHODS: BALB/c mice were sensitized by ovalbumin (OVA, ip) on d 0 and d 14 and challenged with 1% OVA on d 18 to 22. Mice developed airway eosinophilia, mucus hypersecretion, and elevation in cytokine levels. Mice were administered amurensin H orally at the doses of 49, 70, or 100 mg/kg once every day from d 15 to the last day. Bronchoalveolar lavage fluid (BALF) were collected at 24 h and 48 h after the last OVA challenge. Levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 4 (IL-4), interleukin 5 (IL-5), and interleukin 13 (IL-13) in BALF were measured using ELISA method. Differential cell counts of macrophages, lymphocytes, neutrophils and eosinophils were performed in 200 cells per slide (one slide per animal). Lung tissue sections of 6-mum thickness were stained with Mayer's hematoxylin and eosin for assessment of cell infiltration, mucus production, and tissue damage. RESULTS: Oral administration of amurensin H significantly inhibited OVA-induced increases in total cell counts, eosinophil counts, and TNF- alpha, IL-4, IL-5 and IL-13 levels in BALF. In addition, amuresin H dramatically decreased OVA-induced lung tissue damage and mucus production. CONCLUSION: Amurensin H may have therapeutic potential for the treatment of allergic airway inflammation.

Resveratrol inhibits matrix metalloproteinase-9 transcription in U937 cells.

AIM: To examine the inhibitory effect of resveratrol on matrix metalloroteinase-9 (MMP-9) and explore its mechanism. METHODS: MMP-9 activity was analyzed by gelatin zymography; MMP-9 protein was detected by Western blot; MMP-9 mRNA expression was investigated by RT-PCR. Activation of activator protein -1 (AP-1) was measured by electrophoretic mobility shift assay (EMSA). RESULTS: MMP-9 activity in U937 cells increased significantly after exposed to PMA at 10 nmol/L for 24 h without FCS (P<0.01). Resveratrol at 1 and 10 micromol/L showed significant inhibition on MMP-9 activity (P<0.05 and P<0.01, respectively). Western blot and RT-PCR experiments displayed that MMP-9 protein (P<0.01) and mRNA expression (P<0.01) increased significantly in PMA-treated U937 cells. Resveratrol at 1 and 10 micromol/L showed inhibitory effects on MMP-9 protein production and MMP-9 mRNA expression (P<0.05). The activation of AP-1 induced by PMA was also extensively inhibited by resveratrol at 0.1, 1, and 10 micromol/L. CONCLUSION: The inhibitory effect of resveratrol on MMP-9 activity may be partly through suppression of activation of nuclear transcription factor AP-1, and inhibition of MMP-9 mRNA expression and MMP-9 protein production.

[Inhibition of dexamethasone, indomethacin and resveratrol on matrix metalloproteinase-9 and the mechanism of inhibition].

AIM: To investigate the expression of matrix metalloproteinase-9 (MMP-9) in mouse ears induced with croton oil and the inhibitory effect of dexamethasone, indomethacin and resveratrol on MMP-9 expression, and further explore the relationship between anti-inflammation and MMP-9 inhibition of these three medicines. METHODS: Immuno-histochemistry was used to detect the expression of MMP-9 in mouse ears. Expression of MMP-9 in U937 cells was analyzed by gelatin zymography. RESULTS: Mouse ear edema induced with croton oil was inhibited significantly by dexamethasone and indomethacin at the dose of 10 mg.kg-1 and resveratrol at 50 mg.kg-1 administered subcutaneously. The inhibitory rate was 76.2% (P < 0.001), 56.7% (P < 0.001) and 36.9% (P < 0.001) respectively. The MMP-9 expression increased in mouse ears induced with croton oil and inhibited by dexamethasone, indomethacin and resveratrol at above doses. Gelatin zymography results showed that MMP-9 expression in U937 cells increased significantly after exposed to PMA at 1 x 10(-8) mol.L-1 (P < 0.001); MMP-9 expression induced with phorbol myristate acetate(PMA) was inhibited by dexamethasone at 1 x 10(-9), 1 x 10(-7) and 1 x 10(-5) mol.L-1, indomethacin at 1 x 10(-6) and 1 x 10(-5) mol.L-1 and resveratrol at 1 x 10(-6) and 1 x 10(-5) mol.L-1. CONCLUSION: The inhibition of MMP-9 expression may be one of the anti-inflammatory mechanisms of dexamethasone, indomethacin and resveratrol.

[Effect of lipopolysaccharide on expression of interleukin-6 in human synoviocyte from patients with rheumatoid arthritis].

AIM: To study the effects of lipopolysaccharide (LPS), the supernatant of U937 cells stimulated with LPS and dexamethasone on interleukin-6 (IL-6) expression in the synoviocyte from patients with rheumatoid arthritis (RA). METHODS: Fibroblast-like synoviocytes (FLS) from the joint tissue of patients with rheumatoid arthritis were cultured and incubated for 24 h with LPS (1 mg.L-1) or the supernatant of U937 cells stimulated with LPS (1 mg.L-1) for 24 h. Dexamethasone was added to the supernatant of U937 cells and FLS was incubated for 24 h. The expression of IL-6 protein was detected by radioimmunoassay. The mRNA expression of IL-6 was accessed by RT-PCR. RESULTS: The growth of FLS was not markedly affected by LPS, and the protein secretion and mRNA expression of IL-6 were not markedly changed in FLS treated with LPS. The IL-6 secretion and IL-6 mRNA expression were significantly increased in FLS cultured with the supernatant from U937 cell treated with LPS. Dexamethasone markedly inhibited the protein secretion and mRNA expression of IL-6 in FLS cultured with the supernatant from U937 cell stimulated with LPS. The inhibitory effects were increased as the concentration of dexamethasone increased. CONCLUSION: LPS was not shown to directly affect the expression of IL-6 in FLS, but it indirectly causes the increase of the IL-6 expression in FLS by stimulating U937 cell. Dexamethasone can inhibit this increase of the IL-6 expression.

[Effect of lipopolysaccharide on expression of matrix metalloproteinase-9 in human synoviocyte from patients with rheumatoid arthritis].

AIM: To study the effects of lipopolysaccharide (LPS), the supernatant of U937 cells stimulated with LPS and dexamethasone on matrix metalloproteinase-9 (MMP-9) expression in the synoviocyte from patients with rheumatoid arthritis(RA). METHODS: Fibroblast-like cells (FLS) from the joint tissue of patients with rheumatoid arthritis were cultured and incubated for 24 h with LPS (1 mg.L-1) or the supernatant of U937 cells stimulated with LPS (1 mg.L-1) for 24 h. Dexamethasone was added to the supernatant of U937 cells and FLS was incubated for 24 h. The activity of MMP-9 was analyzed by gelatin zymography. Protein expression of MMP-9 was detected by Western blot using special polyclonal antibodies. The mRNA expression of MMP-9 was detected by RT-PCR. RESULTS: The expression of MMP-9 was not markedly changed in FLS treated with LPS. The MMP-9 activity, MMP-9 secretion and MMP-9 mRNA expression were significantly increased in FLS cultured with the supernatant from U937 cell treated with LPS. Dexamethasone markedly inhibited the activity, protein secretion and mRNA expression of MMP-9 in FLS cultured with the supernatant from U937 cell stimulated with LPS, and the inhibitory effects were increased as the concentration of dexamethasone increased. CONCLUSION: LPS did not directly affect the expression of MMP-9 in FLS, but it was found to indirectly cause the increase of MMP-9 expression in FLS by stimulating U937 cell. Dexamethasone was found to inhibit this increase of MMP-9 expression.

Suppression of IL-8 gene transcription by resveratrol in phorbol ester treated human monocytic cells.

Resveratrol (3,4',5-trihydroxy-trans-silbene), a natural phytoalexin found in grapes and other food products, has promising anti-inflammatory and anticancer effects. To observe the modulation of interleukin-8 (IL-8) production in human monocytic cells by resveratrol and explore its mechanism at the gene transcription level, U937 cells were stimulated with phorbol 12-myristate 13-acetate (PMA) for 24h. IL-8 protein in supernatants was measured by radioimmunoassay. The cytotoxicity of PMA, dexamethasone and resveratrol was accessed by MTT cell proliferation assay. The RNA level of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and IL-8 were detected by RT-PCR using specific primers. DNA binding activities of NF-kappaB and AP-1 were examined by electrophoretic mobility shift assay (EMSA). 0.01-100 nM PMA could significantly induce IL-8 production in U937 cells; 10 microM Dexamethasone and 10, 1, 0.1 microM resveratrol could inhibit PMA-induced IL-8 protein production and mRNA accumulation. The cytotoxicity did not contribute to their inhibitory effect. The DNA binding activity of AP-1 was inhibited by dexamethasone and resveratrol, but resveratrol has little effect on PMA-induced NF-kappaB activation. Resveratrol could inhibit PMA-induced IL-8 production in U937 cells at protein and mRNA levels. The suppression of IL-8 gene transcription by resveratrol was, at least partly, due to inhibition of AP-1 activation.