title: Addition of nitric oxide through nitric oxide-paracetamol enhances healing rat achilles tendon.
abstract: Nitric oxide is an important messenger molecule in many physiological processes. The addition of NO via NO-flurbiprofen enhances the material properties of healing tendon, however, flurbiprofen has a detrimental effect on healing. We asked if NO delivered by a cyclooxygenase 3 inhibitor (paracetamol/acetaminophen) would enhance healing in a rat Achilles tendon healing model. Rats were injected subcutaneously daily with NO-paracetamol, paracetamol or vehicle from two days before surgery to the day of tissue harvesting. Paracetamol had no effect on tendon healing compared with vehicle alone. NO-paracetamol did not change the failure load, but did decrease the water content, enhance the collagen content, reduce the cross-sectional area and improve the ultimate stress of healing tendon compared with paracetamol and vehicle. The collagen organization of the healing tendon in the NO-paracetamol group, as determined by polarized light microscopy, was enhanced. Our data suggests NO-paracetamol increases the total collagen content and enhances organization while decreasing the cross-sectional area of healing rat Achilles tendon and is consistent with human clinical trials where NO has improved the symptoms and signs of tendinopathy.
authors.affiliation: Orthopaedic Research Institute, St George Hospital, Research & Education Centre, University of New South Wales, Level 2, 4-10 South Street, Kogarah, Sydney, NSW, 2217, Australia. murrell.g@ori.org.au
authors.forename: George A C
authors.initials: GA
authors.lastname: Murrell
authors.forename: Gongyao
authors.initials: G
authors.lastname: Tang
authors.forename: Richard C
authors.initials: RC
authors.lastname: Appleyard
authors.forename: Piero
authors.initials: P
authors.lastname: del Soldato
authors.forename: Min-Xia
authors.initials: MX
authors.lastname: Wang
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage* / Q000494:pharmacology; D000125:Achilles Tendon / Q000293:injuries*; D000818:Animals; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D006133:Growth Substances / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D009569:Nitric Oxide / Q000008:administration & dosage* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013708:Tendon Injuries / Q000188:drug therapy*; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D006133:Growth Substances; D009569:Nitric Oxide; D000082:Acetaminophen