The Effect of Substance P on an Intervertebral Disc Rat Organ Culture Model

STUDY DESIGN.Laboratory study. OBJECTIVE.Evaluate the effect of substance P (SP) on an intervertebral disc rat organ culture model. SUMMARY OF BACKGROUND DATA.Monolayer cell experiments have demonstrated that exposure intervertebral disc tissue cells to SP leads to upregulation in inflammatory cytokine expression; however, this has not been evaluated in a more complex organ culture model. METHODS.Forty-eight intervertebral discs from eight rats were used in an organ culture model. Intervertebral discs were divided into three groupscontrol, SP-treated group, and a group treated with an SP antagonist followed by SP. Cytokine antibody array was used to quantify expression patterns, which were confirmed using ELISA and real-time polymerase chain reaction. RESULTS.The cytokine array demonstrated a 3.40 ± 0.59-fold increase in interleukin 6 (IL-6) expression in the SP group (P = 0.004), and the effect of SP was mitigated by the SP antagonist (P = 0.03). These results were verified as ELISA demonstrated a significant difference in the IL-6 level between the control group and SP group (0.73 vs. 5.80 ng/mL, P