BACKGROUND:Semaphone 3A(Sema3A)is an important neurovascular growth inhibitor.It is not clear how Sema3A is involved in the pathogenesis of discogenic low back pain.Exploring the potential mechanism of Sema3A in intervertebral disc degeneration can provide a new target and theoretical basis for the prevention and treatment of discogenic low back pain. OBJECTIVE:To explore the mechanism of interleukin-1β inhibiting the expression of Sema3A by activating the nuclear factor-κB signaling pathway to induce intervertebral disc degeneration in rats. METHODS:RT-qPCR was used to detect the expression of Sema3A mRNA in normal and degenerative human nucleus pulposus tissues.Nucleus pulposus cells of Sprague-Dawley rats were isolated,cultured,and passaged to the 3rd generation.Then,passage 3 cells were divided into three groups:the blank control group was routinely cultured for 48 hours,the degeneration group was intervened with 10 ng/mL interleukin 1β for 48 hours,and the degeneration+inhibitor group was treated by 5 μmol/L nuclear factor-κB signaling pathway-specific inhibitor BAY11-7082 for 1 hour,followed by interleukin-1β for 48 hours.At the end of the intervention,cell viability was detected by cell counting kit-8,cell apoptosis was detected by Annexin V/FITC staining,mRNA expression of cellular matrix,vascular and neural markers and Sema3A was detected by RT-qPCR,and protein expression of marker proteins,p65 and p-p65 was detected by western blot. RESULTS AND CONCLUSION:RT-qPCR assay showed that the expression of Sema3A mRNA was lower in degenerative human nucleus pulposus tissue than in normal human nucleus pulposus tissue(P＜0.05).Compared with the blank control group,the nucleus pulposus cell viability decreased and the apoptotic rate increased in the degeneration group(P＜0.05);compared with the degeneration group,the nucleus pulposus cell viability increased and the apoptotic rate decreased in the degeneration + inhibitor group(P＜0.05).Compared with the blank control group,mRNA expression of type Ⅱ collagen,polyproteoglycan,and Sema3A was decreased in the degeneration group(P＜0.05),while mRNA expression of CD31 and neurofilament 200 was increased(P＜0.05).Compared with the degeneration group,mRNA expression of type Ⅱ collagen,polyproteoglycan,and Sema3A was elevated in the degeneration+inhibitor group(P＜0.05)and mRNA expression of CD31 and neurofilament 200 decreased(P＜0.05).Compared with the blank control group,the protein expression of type Ⅱ collagen,polyproteoglycan,and Sema3A was decreased in the degeneration group(P＜0.05),and the protein expression of CD31,neurofilament protein 200,p65,and p-p65 was elevated(P＜0.05);compared with the degeneration group,the protein expression of type Ⅱ collagen,polyproteoglycan,and Sema3A was elevated in the degeneration+inhibitor group(P＜0.05),and protein expression of CD31,neurofilament 200,p65,and p-p65 was decreased(P＜0.05).To conclude,interleukin-1β does inhibit the expression of Sema3A by activating the nuclear factor-κB signaling pathway,which can also increase the degradation of extracellular matrix,promote the innervation and angiogenesis in degenerative intervertebral disc,and may be one of potential factors that contribute to intervertebral disc degeneration and discogenic low back pain.