Reduction in the structural changes of experimental osteoarthritis by a nitric oxide inhibitor

Osteoarthritis Cartilage. 1999 Jul;7(4):416-8. doi: 10.1053/joca.1998.0229.


Objective: To evaluate the in-vivo therapeutic efficacy of N -iminoethyl-L-Lysine (L-NIL), a selective inhibitor of inducible nitric oxide synthase (iNOS) in a dose response study, on the progression of lesions in the experimental osteoarthritic (OA) dog model.

Design: The sectioning of the anterior cruciate ligament of the right stifle joint of mongrel dogs was done by a stab wound. Dogs were separated into experimental groups: Group 1 received no treatment, Groups 2, 3, and 4 received oral L-NIL (0.3, 1 or 10mg/kg/day, respectively) starting immediately after surgery. The OA dogs were killed at 12 weeks after surgery.

Results: Macroscopically, L-NIL decreased the size of the cartilage lesions on condyles and plateaus. The histologic severity of the cartilage lesions was decreased in the L-NIL-treated dogs. This effect was more pronounced at the highest dosage tested (3 and 10mg/kg/day).

Conclusions: This study confirms the effectiveness of L-NIL, a selective inhibitor of iNOS, in attenuating the progression of experimental OA. It also clearly shows that the effect is dose-dependent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dogs
  • Dose-Response Relationship, Drug
  • Lysine / analogs & derivatives*
  • Lysine / therapeutic use
  • Nitric Oxide / physiology*
  • Nitric Oxide Synthase / antagonists & inhibitors*
  • Osteoarthritis / drug therapy*
  • Osteoarthritis / pathology


  • N(6)-(1-iminoethyl)lysine
  • Nitric Oxide
  • Nitric Oxide Synthase
  • Lysine