title: Local NO synthase inhibition produces histological and functional recovery in Achilles tendon of rats after tenotomy: tendon repair and local NOS inhibition.
abstract: Repair of injured tendon is a very slow process and involves the release of many molecules, including nitric oxide. We investigate the influence of local nitrergic inhibition in histological and functional recovery of injured Achilles tendon. A standard murine model of tendon injury by rupture was used. The animals were divided into three experimental groups: control, injury + vehicle (normal saline) and injury + Nω-nitro-L-arginine methyl ester (L-NAME). The products were injected into the paratendinous region every 2 days and body weight gain and Achilles functional index (AFI) were evaluated on days 0, 7, 14 and 21 after tendon injury. On day 21 post-injury, the animals were killed to evaluate nitric oxide production and tissue organization. We observed that tendon surgical division led to increased tissue nitrite levels, which were reduced in L-NAME-treated rats. The AFI revealed functional recovery of L-NAME-treated animals on day 21 post-injury, which was not observed in the saline-treated group. Microscopic analysis of hematoxylin-eosin staining and collagen autofluorescence showed that L-NAME-treated rats had more aligned areas of collagen fibers and that the diameter of newly organized collagen in this group was also greater than that in the vehicle-treated one. We demonstrate that local treatment with L-NAME significantly improves the functional parameters and accelerates histomorphological recovery.
authors.affiliation: Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil. sualessandra@yahoo.com.br
authors.forename: Suellen A S
authors.initials: SA
authors.lastname: Moraes
authors.forename: Karen R M
authors.initials: KR
authors.lastname: Oliveira
authors.forename: Maria E
authors.initials: ME
authors.lastname: Crespo-López
authors.forename: Domingos L W
authors.initials: DL
authors.lastname: Picanço-Diniz
authors.forename: Anderson M
authors.initials: AM
authors.lastname: Herculano
mesh_terms: D000125:Achilles Tendon / Q000201:enzymology / Q000293:injuries / Q000473:pathology; D000818:Animals; D003094:Collagen / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000187:drug effects / Q000502:physiology*; D058971:Tenotomy
chemical_list: D004791:Enzyme Inhibitors; D003094:Collagen; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester