Figure 6

The role of NF-κB in fHA-dependent IVD cell activation. (A) Immunofluorescence staining of intervertebral disc (IVD) cells for NF-κB (p65) (green) following treatment with either hyaluronic acid fragments (fHAs) (20 μg/ml) or interleukin (IL)-1β (5 ng/ml) at selected time points. Nuclear NF-κB (p65) is indicated by arrowheads. Untreated IVD cells served as a control. Scale bar = 50 μm. (B) Western blot analysis of nuclear extracts from untreated IVD cells or cells treated for 1 hour with either fHAs (20 μg/ml) or IL-1β (5 ng/ml). Levels of PARP1 protein served as a loading control. (C) NF-κB (p65) DNA binding activity in nuclear extracts from untreated IVD cells, or cells treated for one hour with IL-1β or fHAs (20 μg/ml) (n = 3). In all cases, analyses were performed in triplicate and values expressed as mean ± S.D. Statistical analysis was performed using the Student's t-test, * P <0.01 as compared to untreated cells.