**2.7 Cytokine assay**

The TMJ tissue was homogenized in buffer (75 mM potassium acetate pH 7.4, 300 mM NaCL, 10 mM EDTA, 0.25% Triton X-100, protease inhibitors). It has previously been shown that TMJ-injected CFA can increase IL-1β (Kerins, Carlson, McIntosh & Bellinger, 2003) . Therefore, the cytokines IL-1 were quantitated from this homogenate using ELISA kits according to the manufacturer's directions (R&D Systems, Minneapolis, MN).
