Hydroxymethylglutaryl co-enzyme A reductase inhibition attenuates endotoxin-mediated inflammatory responses.

Abstract

The aim of this study was to investigate whether inhibition of hydroxymethylglutaryl co-enzyme A reductase attenuates leucocyte-endothelial cell interactions and alters expression of endothelial constitutive nitric oxide synthase (ecNOS) and inducible nitric oxide synthase (iNOS) following exposure to endotoxin. Male Sprague-Dawley rats were randomized into control, lipopolysaccharide (LPS) and pravastatin + LPS groups (seven per group). Pravastatin sodium was gavaged at 0.4 mg per kg per day for 5 days, after which LPS 15 mg/kg was administered via the jugular vein. Intravital microscopy was used to determine leucocyte-endothelial cell interactions. Following the administration of LPS there was a significant reduction in leucocyte rolling velocity at 10 min (mean(s.e.m.) 69(3) versus 102(6) per cent of baseline value; P = 0.041), an increase in the number of adherent leucocytes at 10 min (4.5(0.5) versus 2.8(0.3) per 100 microm; P = 0.044) and an increase in the number of leucocytes undergoing transendothelial migration at 30 min (4.2(0.4) versus 1.7(0.4) per field; P = 0.008) compared with controls. Pretreatment with pravastatin significantly attenuated LPS-induced leucocyte-endothelial cell interactions (rolling velocity 89(6) per cent at 10 min, P = 0.038; adherent leucocytes 3.0(0.5) per 100 microm at 10 min, P = 0.038; migrating leucocytes 1.9(0.5) per field at 30 min, P = 0.001). This endothelial protection was associated with maintenance of ecNOS and reduced iNOS expression within mesenteric tissues. These data show that pravastatin produces anti-inflammatory effects in response to injurious stimuli by attenuation of leucocyte-endothelial cell interactions.