Table of Contents
ISRN Inflammation
Volume 2013, Article ID 907821, 19 pages
http://dx.doi.org/10.1155/2013/907821
Research Article

Marked Effects of Tachykinin in Myositis Both in the Experimental Side and Contralaterally: Studies on NK-1 Receptor Expressions in an Animal Model

1Section for Anatomy, Department of Integrative Medical Biology, Umeå University, 901 87 Umeå, Sweden
2Sports Medicine Unit, Department of Surgical and Perioperative Sciences, Umeå University, 901 87 Umeå, Sweden

Received 28 November 2012; Accepted 18 December 2012

Academic Editors: L. Dagna, P. Gascon, and D. Szukiewicz

Copyright © 2013 Yafeng Song et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Muscle injury and inflammation (myositis) in a rabbit model of an unilateral muscle overuse were examined. It is unknown if the tachykinin system has a functional role in this situation. In this study, therefore, the neurokinin-1 receptor (NK-1R) expression patterns were evaluated. White blood cells, nerve fascicles, fine nerve fibers, and blood vessel walls in myositis areas showed NK-1R immunoreaction. NK-1R mRNA reactions were observable for white blood cells and blood vessel walls of these areas. NK-1R immunoreaction and NK-1R mRNA reactions were also seen for muscle fibers showing degenerative and regenerative features. There were almost no NK-1R immunoreactions in normal muscle tissue. Interestingly, marked NK-1R expressions were seen for myositis areas of both the experimental side and the contralateral nonexperimental side. EIA analyses showed that the concentration of substance P in the muscle tissue was clearly increased bilaterally at the experimental end stage, as compared to the situation for normal muscle tissue. These observations show that the tachykinin system is very much involved in the processes that occur in muscle injury/myositis. The effects can be related to proinflammatory effects and/or tissue repair. The fact that there are also marked NK-1R expressions contralaterally indicate that the tachykinin system has crossover effects.