2024, Vol. 28 ›› Issue (32): 5104-5109

Syringin inhibits intervertebral disc degeneration in rats

Zhang Yunxin1, Zhang Cunxin2, Wang Qian2, Xu Xinliang3, Lyu Chaoliang2, Ni Yong2   

Abstract: BACKGROUND: Intervertebral disc degeneration is caused by damage and degeneration of the nucleus pulposus and annulus fibrosus tissues inside the intervertebral disc, resulting in structural and functional changes of the intervertebral disc. However, there is yet no effective drug treatment for intervertebral disc degeneration.
OBJECTIVE: To investigate the inhibitory effect of syringin on intervertebral disc degeneration.
METHODS: A total of 10 male Sprague-Dawley rats were selected, and the coccygeal intervertebral disc (Co4/Co5) of each rat was set as model group, Co5/Co6 intervertebral disc as syringin group, and Co6/Co7 intervertebral disc as control group. The control group did not receive any treatment. In the model group and syringin group, a miniature puncture needle was used to puncture the annulus fibrosus to establish an intervertebral disc degeneration model. Immediately after modeling, 2.5 μL of normal saline and syringin solution (5 μmol/L) were given in the model and syringin groups, respectively. Four weeks after injection, the samples were taken. The   degree of intervertebral disc degeneration in rats was observed by hematoxylin-eosin and safranine O-fast green staining. The expressions of type II collagen, aggrecan and matrix metalloproteinases 3 and 13 in intervertebral disc tissue were analyzed by immunohistochemical staining.
RESULTS AND CONCLUSION: Hematoxylin-eosin staining showed that in the model group, the height of intervertebral disc decreased, the cartilage endplate became thinner and cracked, the fibrous ring structure was disordered and cracked, and the nucleus pulposus disappeared; in the syringin group, the height of intervertebral disc was normal or slightly lower than that in the control group, the degree of cartilage endplate degeneration was lighter than that in the model group, the fiber circle permutation was relatively regular with no cracks, and the nucleus pulposus was partially shrunk. Safranine O-fast green staining showed that in the model group, the cartilage endplate of the intervertebral disc was defective and the calcified layer of cartilage became thinner, showing obvious degeneration. The structure and morphology of intervertebral disc cartilage endplate in the syringin group recovered to some extent. Immunohistochemical staining showed that, compared with the control group, the expressions of type II collagen and aggrecan in the intervertebral disc cartilage were decreased in the model group (P < 0.000 1), while the expressions of matrix metalloproteinases 3 and 13 increased (P < 0.000 1). Compared with the model group, the expressions of type II collagen and aggrecan in the intervertebral disc cartilage tissue were increased in the syringin group (P < 0.001, P < 0.000 1), while the expressions of matrix metalloproteinases 3 and 13 decreased (P < 0.001, P < 0.000 1). These results showed that syringin could improve the structure and function of intervertebral disc by inhibiting the expression of matrix metalloproteinases 3 and 13 and increasing the expression of type II collagen and aggrecan, thus preventing and slowing down the procession of intervertebral disc degeneration.

Key words: syringin, intervertebral disc degeneration, lumbago, acupuncture, nucleus pulposus cell, monomer of traditional Chinese medicine, matrix metalloproteinase