[Effects of electroacupuncture stimulation of "Jiaji" (EX-B 2) on expression of matrix metalloproteinase-13 and tissue inhibitor of metalloproteinase-1 in intervertebral disc tissue in rabbits with lumbar intervertebral disc degeneration].

OBJECTIVE: To observe the effect of electroacupuncture(EA) stimulation of "Jiaji" (EX-B 2) on the expression of matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of metalloproteinase-1 (TIMP-1) proteins in the lumbar disc in rabbits with lumbar intervertebral disc degeneration so as to explore its mechanism in relieving intervertebral disc degeneration. METHODS: A total of 36 New Zealand rabbits were randomly divided into normal, sham operation (sham), model, and EA groups, with 9 rabbits in each group. The lumbar intervertebral disc degeneration model was established by using a custom-made external loading device to axially compress the lumbar discs (L4, L5) for 28 days in reference to Kroeber and colleagues' methods. After modeling, EA stimulation (2 Hz/15 Hz, 1-2 mA) was applied to bilateral "Jiaji" (EX-B 2) areas for 20 min, once daily for 28 days. The expression levels of MMP-13 and TIMP-1 proteins of the lumbar intervertebral disc (L4-L5) tissues were assayed by Western blot and immunoflorescence methods, separately. RESULTS: Compared to the normal and sham groups, MMP-13 expression levels at the time-points of day 28 in the model group, on day 28 (pre-EA) in the EA group were significantly up-regulated (P < 0.01); and TIMP-1 expression levels on day 28 in both model and EA groups were significantly decreased (P < 0.01). Following EA treatment, the expression level of MMP-13 was notably lower in the EA group than in the model group, and that of TIMP-1 was remarkably higher in the EA group than in the model group (P < 0.01). No significant differences were found in the expression levels of MMP-13 and TIMP-1 from day 1 to day 56 in the same one group of both normal and sham groups, and between these two groups (P > 0.05). CONCLUSION: Electroacupuncture at "Jiaji" (EX-B 2) can effectively suppress intervertebral disc degeneration induced up-regulation of MMP-13 protein and down-regulation of TIMP-1 protein in the disc tissue in rabbits, which may contribute to its effect in bettering lumbago in clinic.