BACKGROUND:Intervertebral disc degeneration is the basis of spinal degenerative diseases;however,there is no effective treatment. OBJECTIVE:To investigate whether sinomenine can inhibit interleukin-1β-induced apoptosis in nucleus pulposus cells and its molecular mechanism. METHODS:Rat nucleus pulposus cells were cultured in vitro by trypsin combined with type II collagenase digestion,and the cell growth curve was plotted.An appropriate sinomenine concentration was determined using the cell counting kit-8 kit.Nucleus pulposus cells were divided into control group,sinomenine group,interleukin-1β group,sinomenine+interleukin-1β group,zinc protoporphyrin group,zinc protoporphyrin+sinomenine group,zinc protoporphyrin+interleukin-1β group,and sinomenine+zinc protoporphyrin+interleukin-1β group.Proliferative activity,reactive oxygen species content,apoptosis rate,and heme oxygenase-1 expression in nucleus pulposus cells were detected. RESULTS AND CONCLUSION:The rat nucleus pulposus cells cultured in vitro were polygonal,triangular,and short wedge-shaped,and the cell growth showed an"S"curve.The cells grew slowly in the first 3 days of culture,rapidly in 4-6 days,and slowly again in 7-8 days.The cells then entered the"platform stage"where the number of cells no longer increased.The proliferative activity of myeloid cells showed no significant changes when the concentration of sinomenine was≤80 μmol/L(P>0.05).Interleukin-1β significantly reduced the proliferative activity of nucleus pulposus cells,increased the content of reactive oxygen species and led to apoptosis(P<0.01).Sinomenine intervention not only promoted heme oxygenase-1 expression(P<0.05)but also inhibited interleukin-1β-induced decrease in proliferative activity and increase in reactive oxygen species content and apoptosis rate in nucleus pulposus cells(P<0.05).These effects could be reversed by zinc protoporphyrin(P<0.01).

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.