High glucose inhibits expression of inducible and constitutive nitric oxide synthase in bovine aortic endothelial cells

Acta Pharmacol Sin. 2000 Apr;21(4):325-8.

Abstract

Aim: To investigate the effects of high glucose on the expression of nitric-oxide synthase (NOS) in cultured bovine aortic endothelial cells (BAEC).

Methods: BAEC were cultured and passaged in normal glucose (NG) 5.5 mmol.L-1, high glucose (HG) 25 mmol.L-1, or high osmolarity (glucose 5.5 mmol.L-1 + mannitol 19.5 mmol.L-1, Mann-BAEC), lipopolysaccharides (LPS)-induced nitric oxide (NO) production was assessed by Griess reaction. The expression of inducible NOS (iNOS) and constitutive NOS (ecNOS) was determined by Western blot.

Results: At a concentration range from 0.5 to 2 mg.L-1, LPS stimulated NO production in NG-BAEC in a concentration-dependent manner. NO production reached the peak level at LPS 1 mg.L-1. HG inhibited NO production, when compared with NG- and Mann-BAEC (nitrite mumol.L-1: HG-BAEC 43 +/- 8, vs NG-BAEC 71 +/- 11, Mann-BAEC 70 +/- 9, n = 4 experiments, P < 0.01). iNOS expression was decreased by 39.9% and 39.3%, and ecNOS by 28% and 24% respectively in HG-BAEC, when compared with NG- or Mann-BAEC. However, no marked difference was observed in the LPS-induced NO production and the expression of iNOS and ecNOS between NG- and Mann-BAEC.

Conclusions: Inhibition of BAEC NO production by HG was mainly due to a decreased expression of NOS protein.

MeSH terms

  • Animals
  • Aorta
  • Cattle
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / enzymology*
  • Glucose / pharmacology*
  • Lipopolysaccharides / antagonists & inhibitors
  • Nitric Oxide Synthase / biosynthesis*
  • Nitric Oxide Synthase Type II
  • Nitric Oxide Synthase Type III

Substances

  • Lipopolysaccharides
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II
  • Nitric Oxide Synthase Type III
  • Glucose