Figure 2.

Effects of IL‐17A or IL‐6 treatment on NP cells under hypoxia. A, Real‐time PCR analysis of rat NP cells treated with 20‐50 ng/mL IL‐17A and cultured under hypoxia (1% O₂). The control cells were not treated with IL‐17A. IL‐17A treatment significantly increased expression of IL‐6, COX‐2, MMP‐3 and MMP‐13 mRNA. Results shown as mean ± SD; n = 4, *P < 0.05. B, C, Western blot analysis of NP cells treated with 50 ng/mL IL‐17A for 24 hours under hypoxic conditions. IL‐17A treatment led to a significant increase in expression of IL‐6 and COX‐2 proteins. Results shown as mean ± SD; n = 3, *P < 0.05. D, Effects of IL‐17A on COX‐2 promoter activity in NP cells. Luciferase activity was assessed to show COX‐2 transcription in NP cells after treatment with 50 ng/mL of IL‐17A. IL‐17A treatment significantly increased COX‐2 promoter transcriptional activity. Results shown as mean ± SD; n = 3, *P < 0.05. E, Alcian blue staining quantifying of NP cells treated with 50 ng/mL IL‐17A. Optical density of the extracted dye was measured at 670 nm. Results shown as mean ± SD; n = 3, *P < 0.05. F, Real‐time PCR analysis of NP cells treated with 50‐100 ng/mL IL‐6 for 24 hours. The control cells were not treated with IL‐6. Treatment with IL‐6 led to significantly increased expression of COX‐2, MMP‐3 and MMP‐13 mRNA but had no effect on IL‐17A mRNA expression. Results shown as mean ± SD; n = 3, *P < 0.05. G, H, Western blot analysis of NP cells treated with 50 ng/mL IL‐6 for 24 hours under hypoxic conditions. IL‐6 treatment led to a significant increase in expression of COX‐2 proteins. Results shown as mean ± SD; n = 3, *P < 0.05. I, Effects of IL‐6 on COX‐2 promoter activity in NP cells. Luciferase activity was used to show COX‐2 promoter transcription in NP cells after treatment with 50 ng/mL of IL‐6, which significantly increased COX‐2 promoter transcription activity. Results shown as mean ± SD; n = 3, *P < 0.05