Inhibitory effects of glucosamine on endotoxin-induced uveitis in Lewis rats

Invest Ophthalmol Vis Sci. 2008 Dec;49(12):5441-9. doi: 10.1167/iovs.08-1784. Epub 2008 Aug 21.


Purpose: Glucosamine sulfate (GS) is a naturally occurring sugar that exerts immunosuppressive effects in vitro and in vivo. The authors investigated whether GS modulates the inflammatory reaction in endotoxin-induced uveitis (EIU) of rats and the mechanisms by which it exerts its effects.

Methods: Two-hundred micrograms of lipopolysaccharide (LPS) was injected subcutaneously into Lewis rats to induce EIU. Doses of GS (10, 100, or 1000 mg/kg) were divided into three aliquots and administered intraperitoneally 30 minutes before LPS injection, concurrently with LPS injection, and 30 minutes after LPS injection. Twenty-four hours after LPS injection, aqueous humor was collected for cell counting and measurement of protein concentration. Immunohistochemical staining of the iris-ciliary body was performed to evaluate the effects of GS on intercellular adhesion molecule (ICAM)-1 and nuclear factor (NF)-kappaB activation and to demonstrate macrophage infiltration. The effects of various doses of GS pretreatment were also examined using a mouse macrophage cell line (RAW264.7 cells) and LPS stimulation. Levels of prostaglandin (PG)-E2 and nitric oxide (NO) were determined. Expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were measured using Western blot analysis. The effect of GS on LPS-induced NF-kappaB activation in RAW cells was also examined.

Results: Cell counting and analysis of protein concentration in aqueous humor revealed that GS suppressed EIU in rats treated with a high dose of GS (1000 mg/kg). Immunohistochemistry showed that treatment with GS reduced ICAM-1 expression and suppressed activation of NF-kappaB in the iris-ciliary body. The main inflammatory cells in the iris-ciliary body during EIU were macrophages. In LPS-stimulated macrophage RAW cell culture, GS inhibited the production of NO and PG-E2, the expression of iNOS and COX-2, and the activation of NF-kappaB.

Conclusions: GS suppresses EIU in rats by blockading the NF-kappaB-dependent signaling pathway and the subsequent production of ICAM-1 and proinflammatory mediators. This study has extended the authors' previous observation that GS is a potentially important compound for reducing ICAM-1-mediated inflammatory effects in the eye.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aqueous Humor / immunology
  • Blotting, Western
  • Cell Count
  • Cell Culture Techniques
  • Ciliary Body / metabolism
  • Cyclooxygenase 2 / metabolism
  • Dinoprostone / metabolism
  • Glucosamine / administration & dosage
  • Glucosamine / pharmacology*
  • Intercellular Adhesion Molecule-1 / metabolism
  • Iris / metabolism
  • Lipopolysaccharides / toxicity*
  • Macrophages / immunology
  • Male
  • NF-kappa B / metabolism
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase Type II / metabolism
  • Rats
  • Rats, Inbred Lew
  • Salmonella typhimurium*
  • Uveitis, Anterior / chemically induced
  • Uveitis, Anterior / metabolism
  • Uveitis, Anterior / pathology
  • Uveitis, Anterior / prevention & control*


  • Lipopolysaccharides
  • NF-kappa B
  • Intercellular Adhesion Molecule-1
  • Nitric Oxide
  • Nitric Oxide Synthase Type II
  • Cyclooxygenase 2
  • Ptgs2 protein, rat
  • Dinoprostone
  • Glucosamine