Figure 5.

Compressive forces upregulate pERK and p P38 in primary hPDL cells. (A) Protein levels and phospho-MAPK (ERK, p38 and JNK) were determined by Western blot in different conditions: HMGB1 (100 ng/mL), TLR4 blocking antibody (5 µg/mL) (TLR4: TLR4 blocking antibody) and compressive force 2 g/cm² at 3 and 24 h. Three different donors showed similar patterns. Under all conditions, ERK, p38 and JNK showed no differences, but the phosphorylated ERK and p38 were significantly upregulated with compressive forces (CF) as follows: ERK for 3 h and p38 for 3 h and 24 h. (B) Quantification of three donors, normalized to the control with stain-free technology. CF conditions without TLR4 blocking antibody showed a significant upregulation for phospho-ERK and phospho-p38. (C) HEK-293 and MC3T3 cells were used as a positive control for phospho-JNK antibody. Data were tested for normal distribution by Shapiro–Wilk test. Afterward, a one-way analysis of variance (ANOVA) followed by Tukeys’ post hoc test was performed. Statistically significant differences to control are marked by asterisks (* p < 0.05; ** p < 0.01).