Endogenous substance P production in the Achilles tendon increases with loading in an in vivo model of tendinopathy: peptidergic elevation preceding tendinosis-like tissue changes
2011 (English)In: Journal of Musculoskeletal and Neuronal Interactions - JMNI, ISSN 1108-7161, Vol. 11, no 2, 133-140 p.Article in journal (Refereed) Published
Objectives: To quantify the intratendinous levels of substance P (SP) at different stages of overload in an established modelfor Achilles tendinopathy (rabbit). Also, to study the distribution of the SP-receptor, the NK-1R, and the source of SP, in thetendon.
Methods: Animals were subjected to the overuse protocol for 1, 3 or 6 weeks. One additional group served as unexercisedcontrols. Immunoassay (EIA), immunohistochemistry (IHC), and in situ hybridisation (ISH) were performed.
Results: EIA revealedincreased SP-levels in the Achilles tendon of the exercised limb in all the experimental groups as compared to in thecontrols (statistically significant; p=0.01). A similar trend in the unexercised Achilles tendon was observed but was not statisticallysignificant (p=0.14). IHC and in ISH illustrated reactions of both SP and NK-1R mainly in blood vessel walls, but the receptorwas also found on tenocytes.
Conclusions: Achilles tendon SP-levels are elevated already after 1 week of loading. This showsthat increased SP-production precedes tendinosis, as tendinosis-like changes occur only after a minimum of 3 weeks of exercise,as shown in a recent study using this model. We propose that central neuronal mechanism may be involved as similar trends wereobserved in the contralateral Achilles tendon.
Place, publisher, year, edition, pages
International Society of Musculoskeletal and Neuronal Interactions, 2011. Vol. 11, no 2, 133-140 p.
Neuropeptides, Neurokinin-1 Receptor, Animal Model, Overuse Injuries, Rabbit
Sport and Fitness Sciences Microbiology in the medical area
IdentifiersURN: urn:nbn:se:umu:diva-42299OAI: oai:DiVA.org:umu-42299DiVA: diva2:409093