Abstract:

Objective

To study the initial responses and the effect of mechanical strain with tyrosine protein kinase TPK and cytochalasin D on the expression of ERK1/2 in osteoblastlike cells in vitro.

Methods

Osteoblast-like cells were cultured with tyrosine protein kinase TPK and cytochalasin D and then subjected to mechanical strain by self-made four-point bending system at a0.5Hz frequency for 5 min， In each time-phase， the cells were loaded with tension and compression stress at 4000 μstrain respectively. The phosphorylation levels of ERK1/2 were measured by Western Blotting. Changes in the experiments were expressed as ratio to the controls（P＜0.05）.

Results

With tyrosine protein kinase TPK blocking agent 4000 μstrain tensile stimulus could induce the expression of ERK in a few minutes， while compressive stimulus could not. On the contrary， the effect with cytochalasin D of compressive tension strain stimulus was more significant.

Conclusions

The reception and transduction of osteoblasts to the mechanical signal of tension or compressive strain are relative to the microfilament cytoskeleton， while the activation of tyrosine protein kinases is mainly connected to response to the tension strain.

Key words: Osteoblast, Extracellular signal regulated kinase, Tyrosine protein kinase, Cytochalasin