[Effect of astragaloside â £ on angiotensin â ¡-induced inflammatory response of vascular endothelial cells and mechanism].

This study was designed to determine the inhibitory effect of astragaloside Ⅳ(AS-Ⅳ), a principal bioactive component extracted from the Chinese medicinal Astragali Radix, on the inflammatory response of vascular endothelial cells induced by angiotensin Ⅱ(Ang Ⅱ), the most major pathogenic factor for cardiovascular diseases, and to clarify the role of calcium(Ca~(2+))/phosphatidylinosi-tol-3-kinase(PI3K)/protein kinase B(Akt)/endothelial nitric oxide synthase(eNOS)/nitric oxide(NO) pathway in the process. To be specific, human umbilical vein endothelial cells(HUVECs) were cultured in the presence of AS-Ⅳ with or without the specific inhibitor of NO synthase(NG-monomethyl-L-arginine, L-NMMA), inhibitor of PI3K/Akt signaling pathway(LY294002), or Ca~(2+)-chelating agent(ethylene glycol tetraacetic acid, EGTA) prior to Ang Ⅱ stimulation. The inhibitory effect of AS-Ⅳ on Ang Ⅱ-induced inflammatory response and the involved mechanism was determined with enzyme-linked immunosorbent assay(ELISA), cell-based ELISA assay, Western blot, and monocyte adhesion assay which determined the fluorescently labeled human monocytic cell line(THP-1) adhered to Ang Ⅱ-stimulated endothelial cells. AS-Ⅳ increased the production of NO by HUVECs in a dose-and time-dependent manner(P<0.05) and raised the level of phosphorylated eNOS(P<0.05). The above AS-Ⅳ-induced changes were abolished by pretreatment with L-NMMA, LY294002, or EGTA. Compared with the control group, Ang Ⅱ obviously enhanced the production and release of cytokines(tumor necrosis factor-α, interleukin-6), chemokines(monocyte chemoattractant protein-1) and adhesion molecules(intercellular adhesion molecule-1, vascular cellular adhesion molecule-1), and the number of monocytes adhered to HUVECs(P<0.05), which were accompanied by the enhanced levels of phosphorylated inhibitor of nuclear factor-κBα protein and activities of nuclear factor-κB(NF-κB)(P<0.05). This study also demonstrated that Ang Ⅱ-induced inflammatory response was inhibited by pretreatment with AS-Ⅳ(P<0.05). In addition, the inhibitory effect of AS-Ⅳ was abrogated by pretreatment with L-NMMA, LY294002, or EGTA(P<0.05). This study provides a direct link between AS-Ⅳ and Ca~(2+)/PI3K/Akt/eNOS/NO pathway in AS-Ⅳ-mediated anti-inflammatory actions in endothelial cells exposed to Ang Ⅱ. The results indicate that AS-Ⅳ attenuates endothelial cell-mediated inflammatory response induced by Ang Ⅱ via the activation of Ca~(2+)/PI3K/Akt/eNOS/NO signaling pathway.

Anti-Acne Vulgaris Effects of Pedunculagin from the Leaves of Quercus mongolica by Anti-Inflammatory Activity and 5α-Reductase Inhibition.

Quercus mongolica (QM)-a member of the Fagaceae family-has been used as traditional medicine in Korea, China and Mongolia as a treatment for inflammation of oral, genital or anal mucosa and for external inflammation of skin. To treat acne vulgaris (AV), we evaluated the inhibition of inflammatory cytokines (IL-6 and IL-8) of QM leaf extract (QML) and its main compound, pedunculagin (PD) in vitro and 5α-reductase inhibitory activity by western blotting. As results, QML and PD showed potent NO production inhibitory activity compared with the positive control (PC), NG-monomethyl-L-arginine (L-NMMA). QML and PD was also showed the decreases of IL-6 and IL-8 compared with the PC, EGCG and exhibited potent 5α-reductase type 1 inhibitory activities compared with the PC, dutasteride.

Measurement of tibial endothelial cell function after cigarette smoking, cessation of smoking and hyperbaric oxygen therapy.

SUMMARY: Cigarette smoking is hazardous to a range of human tissues. For instance, cigarette smoke inhalation has been proven to delay bone healing. This study analysed the effects of cigarette smoking on tibial vascular endothelium and blood flow using the bone-chamber model. The effects of smoking cessation and hyperbaric oxygen (HBO) on the damage caused by smoking were also compared. 54 adult New Zealand rabbits were divided into three groups. Group 1: control, Group 2: 1 week smoking, and Group 3: 6 weeks' smoking. This study on rabbits confirmed that both short-term and long-term cigarette smoking is dangerous to the bony vascular endothelium of the tibia. The vasodilatation caused by nitric oxide production was significantly attenuated in Group 2 and 3's tibia. Long-term smoking damaged the vascular endothelium more severely than short-term smoking (P<.01). Cessation of smoking effectively reduces the adverse effects of smoking when the cessation time equals the smoking time. HBO also effectively reduces the adverse effects of smoking.

Involvement of increased arginase activity in impaired cavernous relaxation with aging in the rabbit.

PURPOSE: Arginase shares L-arginine as a common substrate with nitric oxide (NO) synthase (NOS). We examined whether increased arginase activity is involved in impaired cavernous relaxation with aging in the rabbit. MATERIALS AND METHODS: Young adult (3 to 5 months old) and aged (36 to 48 months old) rabbits were used for the current experiments. Cavernous tissues obtained from the 2 groups were processed for isometric tension experiments, cyclic guanosine monophosphate determination, measurements of NOS and arginase activities, endogenous methylarginines and L-arginine. RESULTS: Carbachol (CCh) produced an endothelium dependent and NO mediated relaxation that was significantly impaired in aged cavernous specimens without change in sodium nitroprusside induced relaxation. Stimulated cyclic guanosine monophosphate production with CCh was significantly decreased in aged cavernous specimens. Ca dependent NOS was predominant in rabbit cavernous specimens. Ca dependent and independent NOS activities remained unchanged in the 2 groups. The tissue contents of N-monomethyl-L-arginine and asymmetric N,N-dimethyl-L-arginine as endogenous NOS inhibitors, symmetrical N,N'-dimethyl-L-arginine and L-arginine as a substrate of NOS were decreased in aged cavernous specimens. Arginase activity was significantly higher in aged cavernous specimens. Impaired CCh induced relaxation in aged cavernous specimens was normalized in the presence of N-hydroxy-L-arginine as an arginase inhibitor or by the supplementation of excess L-arginine. CONCLUSIONS: These results strongly suggest that impaired endothelium dependent and NO mediated cavernous relaxation with aging is due to decreased NO production, which would result from increased arginase activity and probably from decreased L-arginine content.

Accumulated endogenous NOS inhibitors, decreased NOS activity, and impaired cavernosal relaxation with ischemia.

We examined whether endogenous inhibitors of nitric oxide (NO) synthesis are involved in the impaired cavernosal relaxation with ischemia in rabbits. Two weeks after cavernosal ischemia caused by partial vessel occlusion, endothelium-dependent and electrical field stimulation (EFS)-induced neurogenic NO-mediated relaxations, but not sodium nitroprusside (SNP)-induced relaxation, were significantly impaired in the isolated corpus cavernosum. The Ca(2+)-dependent NO synthase (NOS) activity and the basal and stimulated cGMP productions with carbachol or EFS were significantly decreased after ischemia. Supplementation of excess L-arginine partially recovered both of the impaired relaxations. The contents of N(G)-monomethyl-L-arginine (L-NMMA) and asymmetric N(G), N(G)-dimethyl-L-arginine (ADMA) but not L-arginine and symmetric N(G),N'(G)-dimethyl-L-arginine (SDMA) were increased in the cavernosal tissues after ischemia. Authentic L-NMMA and ADMA but not SDMA concentration dependently inhibited both relaxations without affecting the relaxation produced by SNP in the control. Excess L-arginine abolished the inhibition with L-NMMA and ADMA. These results suggest that the impaired NO-mediated cavernosal relaxations after ischemia are closely related to the decreased NOS activity and the increased accumulation of L-NMMA and ADMA.

Blockade of cytochrome P-450 epoxygenase pathway attenuates the natriuresis of N(G)-monomethyl-L-arginine infusion in the spontaneously hypertensive rat.

Previous studies demonstrated that there is increased renal synthesis of cytochrome P-450-dependent arachidonic acid metabolites in the vasculature and tubules of the Okamoto spontaneously hypertensive rat (SHR). It has also been shown that the natriuretic response of the SHR to NG-monomethyl-L-arginine (L-NMMA) infusion is exaggerated compared with that of the normotensive Wistar-Kyoto rat. The purpose of this study was to determine the roles of cytochrome P-450 epoxygenase and cyclooxygenase pathways in the natriuresis that is observed with the systemic infusion of a high dose of L-NMMA to inhibit nitric oxide synthesis in the SHR and the Wistar-Kyoto rats. After a control clearance period of 20 minutes groups of adult SHR (n = 14) were given L-NMMA (15 mg/kg bolus followed by 500 microg/kg/min continuous infusion). In other groups of SHR either ketoconazole (0.5 mg/kg, n = 9) to inhibit the renal activity of cytochrome P-450 epoxygenase pathway or indomethacin (3 mg/kg, n = 7) to inhibit cyclooxygenase activity was administered intravenously 20 minutes before the control clearance period. After the control clearance period L-NMMA was infused as previously described. Infusion of L-NMMA in the control group of SHR resulted in a significant increase in fractional excretion of sodium (FE Na from 1.78% +/- 0.24% to 6.90% +/- 0.61%). In the ketoconazole-treated group of SHR, L-NMMA infusion resulted in a significant natriuresis (from 2.22% +/- 0.58% to 4.70% +/- 0.93%); however, the natriuretic response was significantly attenuated compared with that of the control group of SHR that received only L-NMMA (delta FE Na, 2.47% +/- 0.40% vs 5.24% +/- 0.55%). Indomethacin administration did not affect the natriuretic response to L-NMMA infusion in the SHR. In conclusion, the natriuretic response to L-NMMA infusion in the SHR is significantly attenuated by administration of ketoconazole but not indomethacin. This result suggests that the natriuretic effect of L-NMMA infusion in the SHR is mediated at least partly by cytochrome P-450 metabolites of the epoxygenase pathway.