Study on the expression of nerve growth associated protein-43 in rat model of intervertebral disc degeneration

OBJECTIVE In the present work we studied the expression of nerve growth associated protein (GAP-43) in a rat model of intervertebral disc degeneration. METHODS 16 healthy adult SD rats, male or female, with an average weight 220g were selected. FluoroGold was injected in L5-L6 disc as the tracer. After 7 days, Freund's adjuvant was then injected to build model of intervertebral disc degeneration. After 1, 3, 7 and 14 days of modeling immune-histochemical method was used to detect the T13-L6 dorsal root ganglion and positive expression of GAP-43, TNF-α and IL-1 in L5-L6 intervertebral disc; RT-PCR method was used to detect GAP-43 mRNA and Western blot method was utilized to detect the expression levels of protein. RESULTS In the observation group, the dorsal root ganglion, positive expression rates of GAP-43, TNF-α and IL-1, expression levels of GAP-43 mRNA and protein in the intervertebral disc at each time point were significantly higher than those in the control group, and the differences were statistically significant (P⟨0.05); the positive expression rates of GAP-43, TNF-α and IL-1, expression levels of GAP-43 mRNA and protein of the observation group reached the peak at 3d, and dropped at 7d; dorsal root ganglion reached the peak at 7d and dropped at 14d. CONCLUSION Degenerative changes might be mediated by the abnormal high expression of GAP-43 and intervertebral disc inflammation jointly.