Aim: The aim of the study was to investigate the effects of dexamethasone and cyclic mechanical strain on human bone marrow stromal cells (hBMSCs) in osteogenic differentiation by determing levels of mRNA of collagen I, II, III, tenascin C and Cbfa1.
Method: hBMSCs from seven donors (32.5 +/- 6.2 years old) were cultivated with (D +) or without (D -) dexamethasone. After the second passage 2.2 x 10 (5) cells were seeded on flexible silicon dishes. A cyclic mechanical strain with an elongation of 2 % (D + 2; D - 2) or 8 % (D + 8; D - 8) was applied for three days with a stimulation time of three times for two hours each day. Cells were harvested on day 1, day 1 after stress (day 4) and day 4 after stress (day 7). mRNA expression of collagen I, II, III, tenascin C and Cbfa1 was investigated by RT-PCR.
Results: Cbfa1 mRNA levels were significantly different on different days (p < 0.05), and for strain on day 1: 8 %: 0.0291 +/- 0.0338 versus 0 %: 0.00 528 +/- 0.0127, p = 0.017; day 8: 8 %: 0.0411 +/- 0.116, 0 %: 0.00 103 +/- 0.00 217, p = 0.009. All other observed paramaters showed tendencies without significant differences.
Conclusion: In the short-term over seven days, cyclic stretching is a stronger differentiation factor than dexamethasone.