Objectives One of the most common diseases of the musculoskeletal system is osteoarthritis (OA). Recent studies claim, that whole body vibration (WBV) has a beneficial influence on cartilage mediating the delay or even reversion of its degeneration. Our aim was to develop an in vitro vibration procedure for cultivated chondrocytes and the analysis of the influence of vibration on inflammatory and cell stimulating processes, to identify protective or synergistic effects with cytokines and growth factors.
Methods Chondrocytes of human cartilage of 3 donors were isolated and expanded up to passage 3. Then, cells were seeded in a density of 10.000 cells/cm2 in six well plates. After 48h, chondrocytes were induced with 10ng/ml tumor necrosis factor alpha (TNFα), 10ng/ml insulin-like growth factor 1 (IGF1), 5ng/ml transforming growth factor beta 1 (TGFβ1) or not induced as a control. TNFα was used to induce inflammatory processes. IGF1 and TGFβ1 act as chodroprotective and chondroinductive agents. Cells were either mechanically stimulated with a custom-made WBV plate for 30min at a frequency of 30Hz and 0.3g every 24h or remained unstimulated. After 48h, RNA was isolated and transcribed for real-time detection polymerase chain reaction (RTD PCR). Gene expression of chondrocytes stimulated or not with TNFα, IGF1 and TGFβ1 before vibration was compared with that of chondrocytes treated in a similar manner without vibration. For TNFα stimulated cells, gene expression of interleukin 1 beta (IL1β) and matrix metalloproteinase (MMP)3 and 13 were chosen. Additionally, for TNFα stimulation and chondroinduction by IGF1 and TGFβ1, gene expression of aggrecan (ACAN), biglycan (BGN), cartilage oligomeric protein (COMP), collagen (COL) 1, 2, 10, and serpin family E member 1 (SERPINE1) was evaluated.
Results and Conclusion During vibration, no cell detachment from the culture plate occurred. For non-vibrated cells, TNFα stimulation led to an increase in the expression of the proinflammatory and catabolic genes IL1β and MMP. Interestingly, the vibration induced changes in gene expression of these markers IL1β and MMP. Stimulation of TGFβ1 resulted, irrespectively whether vibration was applied or not, in an increase in COL1, COL10, COMP and SERPINE1 gene expression. IGF1 stimulation elevated expression of the chondrogenic genes ACAN and COL2. In comparison to the TGFβ1 stimulation, vibration induced slight changes in gene expression.
Taken together, vibration did not impair cell survival or mediate inflammatory stress in chondrocytes. Further, it did not change the gene expression induced by TGFβ1. In cells stimulated with IGF1 and TNFα, slight synergistic respectively inhibitory influences by vibration were found. These results indicate a potential use of WBV for patients with OA. Further in vivo studies have to be performed. The invented vibration protocol could be promising to stabilize the anabolic capacity of chondrocytes in vitro e.g. in combination with growth factors such as IGF1.
Stichwörter osteoarthritis, low magnitude, high frequency vibration, chondrocytes, inflammation, chondroinduction
