Figure 5.

Evaluation of osteogenic differentiation of human osteoblasts following biophysical stimulation. Relative gene expression of osteogenic markers for bone formation: (A) collagen type I alpha 1 chain (COL1A1), (B) alkaline phosphatase (ALP), and (C) osteocalcin (OC) in human osteoblasts after treatment with micromotions and electrical stimulation (MM + ES) compared to osteoblasts treated solely with micromotions (MM) and osteoblasts treated with titanium bodies and electrical stimulation (Load + ES). Gene expression levels of COL1A1, ALP, and OC were determined via semi-quantitative polymerase chain reaction (qPCR). Results are presented as boxplots of the percentage of 2^(−ΔΔCt) related to loaded controls (n ≥ 6). (D) Synthesis rates of osteogenic markers procollagen type 1 and alkaline phosphatase (ALP) in human osteoblasts. The release of type I C-terminal collagen propeptide in the cell culture supernatant was determined using ELISA and related to the total protein concentration. The ALP activity was determined colorimetrically by the hydrolysis of p-nitrophenyl phosphate. Results are presented as box plots related to the loaded controls (n ≥ 6). * p < 0.05, ** p < 0.01 compared to the loaded controls (Wilcoxon’s signed-rank test); ^# p < 0.05, ^## p < 0.01 comparison between different parameters (Mann–Whitney U test); ^§ p < 0.05, ^§§ p < 0.01 comparison between different treatment groups (Mann–Whitney U test).