Visual acupotomy intervention mitigates pain reaction by improving intervertebral disc degeneration and inhibiting apoptosis of nucleus pulposus cells in rabbits with cervical spondylosis

Abstract

To investigate the effect of visual acupotomy intervention on intervertebral disc degeneration, nucleus pulposus cell apoptosis and expression of apoptosis related proteins in rabbits with cervical spondylosis (CS), so as to explore its mechanism underlying improvement of CS. A total of 48 male New Zealand rabbits were randomly divided into blank control, model, acupotomy and medication (meloxicam) groups, with 12 rabbits in each group. The neck type CS model was established by forcing the rabbit to make a neck flexion for 5 hours in a restrained chamber, once daily for 12 weeks. Rabbits of the medication group received an intramuscular injection of meloxicam (0.35 mg/kg), once daily for 4 consecutive weeks, and those of the acupotomy group received ultrasound-guided acupotomy intervention, once a week for 4 weeks. The pain threshold (PT) was measured by using a VonFrey electronic pain detector. The levels of prostaglandin E2 (PGE2), 5-hydroxytryptamine (5-HT) and substance P (SP) in serum were detected by ELISA. The severity of intervertebral disc degeneration was observed by using magnetic resonance imaging (MRI) and given scores in accordance with Suzuki's and colleague's "new classification system of cervical disk degeneration". The apoptosis of nucleus pulposus cells was analyzed by TUNEL staining. The protein expression levels of apoptosis-related protein Fas, cysteinyl aspartate-specific protease-3 (Caspase-3), B-cell lymphoma-2 asso-ciated X protein (Bax) and B-cell lymphoma-2 protein (Bcl-2) were measured by Western blot. Compared with the blank control group, the PT and Bcl-2 expression and MRI score were significantly down-regulated (P<0.01, P<0.001), whereas the contents of serum PGE2, 5-HT and SP, ratios of TUNEL-positive cells, and expression of Fas, Caspase-3 and Bax were considerably up-regulated (P<0.001, P<0.05, P<0.01) in the model group. In contrast to the model group, both the medication and acupotomy groups had an obvious increase in the levels of PT and Bcl-2 expression and MRI score (P<0.05, P<0.01), and a significant decrease in the contents of serum PGE2, 5-HT, SP, ratios of TUNEL-positive cells, and expression of Fas, Caspase-3 and Bax proteins (P<0.05). No significant differences were found between the medication and acupotomy groups in all the indexes mentioned above (P>0.05). Visual acupotomy intervention can mitigate the pain state of CS rabbits, which may be related to its functions in improving the intervertebral disc degeneration, reducing inflammatory reactions and apoptosis of nucleus pulposus cells.