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Modulation of tendon healing by nitric oxide
G A Murrell1, C Szabo, J A Hannafin
1Laboratory for Soft Tissue Research, Cornell University Medical College, Hospital for Special Surgery, New York, NY 10021, USA.
Summary
Nitric oxide (NO) plays a crucial role in tendon healing. Inhibiting NO synthase significantly impairs the healing process in rat Achilles tendons, highlighting NO
Area of Science:
- Biomedical Science
- Molecular Biology
- Tissue Repair Mechanisms
Background:
- Nitric oxide (NO) is a signaling molecule derived from L-arginine by nitric oxide synthases (NOS).
- The role of NO in the complex process of tendon healing remains largely unexplored.
Purpose of the Study:
- To investigate the expression and function of NO during the healing of surgically divided rat Achilles tendons.
- To determine the impact of inhibiting NO synthase on tendon repair and mechanical properties.
Main Methods:
- Assessed NO synthase activity and immunoreactivity in uninjured and healing rat Achilles tendons at different time points post-surgery.
- Administered N-omega-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor, or its enantiomer (D-NAME) orally to rats.
- Evaluated the effects of L-NAME on tendon cross-sectional area and failure load during healing.
Main Results:
- NO synthase activity and immunoreactivity were upregulated significantly at day 7 post-injury in healing tendons.
- Inhibition of NO synthase with L-NAME markedly reduced tendon cross-sectional area (up to 50%) and failure load (24%).
- Administration of D-NAME did not impede normal tendon healing, confirming the specificity of L-NAME's effects.
Conclusions:
- Tendon healing involves the induction of nitric oxide synthase.
- Inhibition of NO synthase activity negatively impacts tendon repair, reducing structural integrity and mechanical strength.
- NO is essential for effective tendon healing, suggesting potential therapeutic targets for tendon injuries.