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Iterated micro‐trauma stimulates tendon healing via a gene expression pattern similar to early mechanical loading. Study on rat Achilles tendons.
Author(s) -
Eliasson Pernilla,
Hammerman Malin,
Aspenberg Per
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.941.6
Subject(s) - dry needling , achilles tendon , tendon , gene expression , inflammation , endocannabinoid system , medicine , gene , wound healing , anatomy , chemistry , surgery , pathology , biochemistry , acupuncture , alternative medicine , receptor
The objective of this study was to compare the gene expression response in healing unloaded rat Achilles tendons after micro‐trauma with previous findings after mechanical loading. 44 rats were given Botox into the calf muscle to reduce loading, and the Achilles tendon was transected. The healing tissue was traumatized by needling with a thin needle. qPCR for 18 genes, known to be regulated by loading, was performed 15 min and 3 h after a single needling episode. Mechanical properties of the tendon were measured after 4 consecutive days with needling, and showed increased strength of the tendon callus by 46%. 14 genes were significantly different from controls. 3 were regulated after 15 min, including up‐regulation of early growth response 1. 11 genes were regulated after 3 h; mainly genes involved in inflammation and coagulation. Trauma induced almost the same genes as loading, but there were differences in the level of increase. Inducible nitric oxide synthase was up‐regulated 38 times after trauma compared to 6 times after loading. A similar pattern was seen for other genes involved in inflammation. In conclusion, there was a striking similarity between the gene expression response to needling and mechanical loading. This suggests that the response to loading in early tendon healing can, at least in part, be a response to micro‐damage. This study was funded by the Swedish Research Council.