Objective To observe the effect of Psoralens on cartilage degeneration in lumbar intervertebral disc of rats induced by interleukin-1β（ IL-1β） and research its internal mechanism of delaying disc degeneration. Methods The cartilages of lumbar intervertebral disc in 1-month-old female SD rats were isolated in vitro. The cells were cultured by tissue explant method and the cells were identified by HE staining

toluidine blue staining and immunofluorescence. The optimal concentration of Psoralens was screened by cell proliferation assay and RT-PCR method. The 3rd generation cartilage cells were selected and placed in a 6-well plate at a concentration of 1 × 105/ well. The cells were divided into the blank control group

IL-1β-induced group（10 ng / ml IL-1β） and Psoralens group（10 ng / ml IL-1β

added with the optimal concentration of Psoralens）

with 3 wells in each group. The expressions of type II collagen gene（Col2a1）

Aggrecan

A Disintegrin and Metalloproteinase with Thrombospondin Motifs 5（ ADAMTS-5）

IL-1β and cyclooxygenase-2（COX-2） mRNA were detected. Results Comparing with concentration of zero

the cell activity of Psoralens was significantly weakened at concentrations of 100

150

200 and 400 μM（P < 0. 01）. Comparing with concentration of zero

the expression of Col2a1 mRNA was significantly increased at concentrations of 12. 5 and 25 μM（P < 0. 05 or P < 0. 01）. The expression of Aggrecan mRNA in the Psoralens group was significantly higher than that in the blank control group（ P < 0. 01）. Comparing with the IL-1-induced group

the expression of Col2a1 mRNA was significantly increased but the expression of ADAMTS-5 mRNA was significantly decreased in the Psoralens group（P < 0. 01）. Conclusion Psoralens can alleviate IL-1β-induced cartilage degeneration of intervertebral disc and affect the related factors of IL-1β signaling pathway