Role of MAP kinases in mediating the effects of fHAs in IVD cells. Cultured intervertebral disc (IVD) cells were treated for 15 minutes with hyaluronic acid fragments (fHAs) (20 μg/ml), interleukin (IL)-1β (5 ng/ml), lipopolysaccharide (LPS) (25 ng/ml) or left untreated and whole cell extracts harvested for Western blot analysis using antibodies specific to phosphorylated and non-phosphorylated SAPK/JNK (54/46) (A), ERK 1/2 (44/42) (B) and p38 (C). (D, E) IVD cells were treated with fHA (20 μg/ml) alone (Control) or in combination with MAP kinase inhibitors (10 μM) specific for p38 (SB203580), ERK 1/2 (PD98059) or SAPK/JNK (SP600125) and IL-6 (D) and matrix metalloproteinase (MMP)-3 (E) protein levels determined by specific ELISA (n = 4). In all cases, analyses were carried out in triplicate and values expressed as mean ± S.D. Statistical analysis was performed using Students t-test, * P <0.05, ** P <0.01 as compared to cells treated with fHAs alone (Control).
Quero et al. Arthritis Research & Therapy 2013 15:R94 doi:10.1186/ar4274