Mitchel C Whittal1, Sarah J Poynter2, Kayla Samms2, K Josh Briar1, Sabrina I Sinopoli1, Magali Millecamps3, Laura S Stone3,4, Stephanie J DeWitte-Orr2, Diane E Gregory5,6. 1. Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L 3C5, Canada. 2. Department of Health Sciences, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L 3C5, Canada. 3. McGill University, 845 Sherbrooke Street West, Montréal, QC, H3A 0G4, Canada. 4. University of Minnesota, 321 Church Street SE, Minneapolis, MN, 55455, USA. 5. Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L 3C5, Canada. dgregory@wlu.ca. 6. Department of Health Sciences, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L 3C5, Canada. dgregory@wlu.ca.
Abstract
PURPOSE: Intervertebral disc (IVD) degeneration is accompanied by mechanical and gene expression changes to IVDs. SPARC-null mice display accelerated IVD degeneration, and treatment with (toll-like receptor 4 (TLR4) inhibitor) TAK-242 decreases proinflammatory cytokines and pain. This study examined if chronic TAK-242 treatment impacts mechanical properties and gene expression associated with IVD degeneration in SPARC-null mice. METHODS: Male and female SPARC-null and WT mice aged 7-9 months were given intraperitoneal injections with TAK-242 or an equivalent saline vehicle for 8 weeks (3x/per week, M-W-F). L2-L5 spinal segments were tested in cyclic axial tension and compression. Gene expression analysis (RT-qPCR) was performed on male IVD tissues using Qiagen RT2 PCR arrays. RESULTS: SPARC-null mice had decreased NZ length (p = 0.001) and increased NZ stiffness (p < 0.001) compared to WT mice. NZ length was not impacted by TAK-242 treatment (p = 0.967) despite increased hysteresis energy (p = 0.024). Tensile stiffness was greater in SPARC-null mice (p = 0.018), and compressive (p < 0.001) stiffness was reduced from TAK-242 treatment in WT but not SPARC-null mice (p = 0.391). Gene expression analysis found upregulation of 13 ECM and 5 inflammatory genes in SPARC-null mice, and downregulation of 2 inflammatory genes after TAK-242 treatment. CONCLUSIONS: TAK-242 had limited impacts on SPARC-null mechanical properties and did not attenuate NZ mechanical changes associated with IVD degeneration. Expression analysis revealed an increase in ECM and inflammatory gene expression in SPARCnull mice with a reduction in inflammatory expression due to TAK-242 treatment. This study provides insight into the role of TLR4 in SPARC-null mediated IVD degeneration.
PURPOSE: Intervertebral disc (IVD) degeneration is accompanied by mechanical and gene expression changes to IVDs. SPARC-null mice display accelerated IVD degeneration, and treatment with (toll-like receptor 4 (TLR4) inhibitor) TAK-242 decreases proinflammatory cytokines and pain. This study examined if chronic TAK-242 treatment impacts mechanical properties and gene expression associated with IVD degeneration in SPARC-null mice. METHODS: Male and female SPARC-null and WT mice aged 7-9 months were given intraperitoneal injections with TAK-242 or an equivalent saline vehicle for 8 weeks (3x/per week, M-W-F). L2-L5 spinal segments were tested in cyclic axial tension and compression. Gene expression analysis (RT-qPCR) was performed on male IVD tissues using Qiagen RT2 PCR arrays. RESULTS: SPARC-null mice had decreased NZ length (p = 0.001) and increased NZ stiffness (p < 0.001) compared to WT mice. NZ length was not impacted by TAK-242 treatment (p = 0.967) despite increased hysteresis energy (p = 0.024). Tensile stiffness was greater in SPARC-null mice (p = 0.018), and compressive (p < 0.001) stiffness was reduced from TAK-242 treatment in WT but not SPARC-null mice (p = 0.391). Gene expression analysis found upregulation of 13 ECM and 5 inflammatory genes in SPARC-null mice, and downregulation of 2 inflammatory genes after TAK-242 treatment. CONCLUSIONS: TAK-242 had limited impacts on SPARC-null mechanical properties and did not attenuate NZ mechanical changes associated with IVD degeneration. Expression analysis revealed an increase in ECM and inflammatory gene expression in SPARCnull mice with a reduction in inflammatory expression due to TAK-242 treatment. This study provides insight into the role of TLR4 in SPARC-null mediated IVD degeneration.
Authors: Mohamad Bydon; F M Moinuddin; Yagiz U Yolcu; Waseem Wahood; Mohammed Ali Alvi; Anshit Goyal; Mohammed Elminawy; Catalina Galeano-Garces; Amel Dudakovic; Ahmad Nassr; A Noelle Larson; Andre J van Wijnen Journal: Gene Date: 2020-03-30 Impact factor: 3.688