Beneficial effect of HCL-31D in murine models of endotoxaemia

Abstract

We evaluated the effect of HCL-31D, a novel cAMP-specific phosphodiesterase inhibitor, on the induction of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma)-treated rat aortic smooth muscle cells (RASMC) and on survival in a murine model of severe endotoxaemia. Treatment of cultured RASMC with LPS and IFN-gamma resulted in an increase of nitrite, tumour necrosis factor (TNF-alpha) production and induction of iNOS mRNA. However, incubation with HCL-31D (1 approximately 50 microM) for 24 h caused significant attenuation of nitrite and TNF-alpha formation as well as iNOS mRNA induction in a dose-dependent manner but no effect on iNOS activity in RASMC. In addition, administration of HCL-31D (5 mg/kg, i.p.) resulted in that the increase of both plasma nitrate and TNF-alpha levels induced by LPS in vivo was significantly reduced in LPS-treated rats. Treatment of conscious mice with a high dose of LPS (60 mg/kg, i.p.) to ICR mice resulted in a 24-h survival rate of only 10%. However, administration of HCL-31D (5 mg/kg, i.p. at 0 h and 6 h after LPS) improved the 24-h survival to 50%, indicating that HCL-31D has a beneficial effect in murine model endotoxaemia. These effects may be mainly due to inhibition of TNF-alpha formation and of the induction of iNOS. We proposed that the elevation of cAMP levels by HCL-31D may be involved in the prevention of TNF-alpha formation and iNOS induction.

Amlodipine Inhibits Pro-inflammatory Cytokines and Free Radical Production and Inducible Nitric Oxide Synthase Expression in Lipopolysaccharide / Interferon-γ-Stimulated Cultured Vascular Smooth Muscle Cells

“…RASMC were cultured and prepared as previously described (14). To examine the effects of amlodipine, RASMC were treated with LPS (100 mg/mL) and IFN-g (100 U /mL) for 24 h in the presence or absence of amlodipine (0.1 -10 mM).…”

“…Medium nitrite and serum NOX were determined by using the Griess reagent and a Sievers Nitrite Oxide Analyzer (Sievers 280 NOA; Sievers, Boulder, CO, USA), respectively, as previously described (14).…”

Anti-inflammatory activity of c-phycocyanin in lipopolysaccharide-stimulated RAW 264.7 macrophages

“…However, the high amount of NO produced by inducible NOS (iNOS) stimulated by pro-inflammatory cytokines, free radicals and lipopolysaccharide (LPS) may be a critical mediator in the pathogenesis of inflammatory diseases (Vane et al, 1994;Szabó and Thiemermann, 1995). In sepsis and other inflammationrelated diseases, attenuation of iNOS/NO pathway has been proven beneficial (Blantz and Munger, 2002;Chou et al, 2001;MacMicking et al, 1995). Furthermore, it is well known that activated macrophages play an important role in the regulation of inflammation and immune response through producing various inflammatory mediators, including pro-inflammatory cytokines, NO and reactive oxygen species (ROS), which are then released into the general circulation to exert systemic effects (Fujii et al, 1998;West et al, 1994;Williams and Shacter, 1997).…”

Liquid Perfluorochemical Inhibits Inducible Nitric Oxide Synthase Expression and Nitric Oxide Formation in Lipopolysaccharide-Treated RAW 264.7 Macrophages

“…Cell viability was assessed by the mitochondriadependent reduction of 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide (MTT) to formazan as previously described (15).…”

“…However, high output NO production by inducible NOS (iNOS) stimulated by pro-inflammatory cytokines, free radicals, and lipopolysaccharide (LPS) participates in the pathogenesis of inflammatory diseases including sepsis (13,14). The LPS-induced inflammatory response and high mortality were all significantly attenuated in both iNOS-deficient mice or mice treated with iNOS inhibitor (15,16), further suggesting that suppression of iNOS-derived NO overproduction may be a potential strategy for treating inflammatory diseases. Additionally, a large number of activated macrophages often found in injured tissues are major producers of inflammatory mediators including pro-inflammatory cytokines, NO, and ROS, which have been implicated in the pathogenesis of inflammatory diseases (17,18).…”