Physical activity reduces dysregulation of the inflammatory mediators in the multifidus muscle after spontaneous intervertebral disc degeneration in SPARC-null mice
Hodges PW, James G, Millecamp M, Stone L
1. School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, QLD, Australia;
2. Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
A pro-inflammatory response is present in the multifidus muscle after an intervertebral disc lesion and is proposed to drive structural alterations in back muscles in low back pain(1). These changes are purported to contribute to persistence and worsening of the condition. Exercise and physical activity produce a strong anti-inflammatory response but the effectiveness in ameliorating inflammation in the multifidus muscle is unknown. We assessed the inflammatory profile of multifidus using SPARC-null mice that develop spontaneous intervertebral disc degeneration (IDD) and whether physical activity could prevent changes. Wild-type and SPARC null mice were sedentary or housed with a running wheel. Multifidus muscle segments were harvested from L2-L6 from the mice at 9 months after an MRI scan to determine levels with IDD. Multifidus inflammatory profile was examined using real time PCR assays. Inflammatory cytokine expression was considered with respect to proximity to levels with IDD and compared between wild-type and SPARC-null mice and those with and without exposure to physical activity. Spontaneous IDD in the SPARC-null mice caused dysregulation of interleukin-1beta (IL-1β), interleukin 6 (IL6), Transforming growth factor beta1 (TGFβ1) and adiponectin expression. The proximity and degree of IDD was related to levels of IL-β1 expression. Physical activity reduced the pro-inflammatory response to IDD in multifidus. IL-1β, tumor necrosis factor, interleukin-10, adiponectin, and leptin levels were lower in the physically active group. These results reveal that spontaneous IDD dysregulates the inflammatory pathways active in the multifidus muscle. Alterations were related to the severity of IDD and were prevented by physical activity.
1. Hodges PW, James G, Blomster L, Hall L, Schmid A, Shu C, Little C, Melrose J (2014) Spine, 39(13), 1010-7.