Zetos: Ein Kulturbelastungssystem für trabekuläre Knochen. Untersuchung eines Belastungssignals mit verschiedenen Intensitäten an bovinen Knochenzylindern

The aim of this study was to show the influence of different amplitudes (1000, 1500, 2000, 3000, 4000µstrain) of the physiological jumping signal, which was applied to bovine bone samples with the ZETOS loading system. The bone samples were provided with DMEM medium in special culture and loading chambers for 26 days. 48 bovine bone samples were randomised and divided into 6 groups, 5 loaded groups and 1 control group. To achieve the stiffness changes Young´s modulus was measured before started the mechanical loading procedure. The loaded groups got a daily YM measurement and the control every 3rd day. Significant differences of stiffness increase were obtained between the control group and loaded groups, which received intensity higher than 1500µstrain. In the groups which achieved a jumping signal of 2000- and 3000µstrain a continuous increase of stiffness could be detected until the end of the run. In these groups a significant amount of new formed osteoid was determined in comparence to the control group. The 4000µstrain group reached a maximum stiffness at the 8th day of applied load and stayed stabile until the end of this experiment. In this group the investigated osteoid thickness was equal to the groups, which received a load of 2000- and 3000µstrain. A correlation could be detected (r=0.87) between the increase of the amplitude of the jumping signal and the increase of osteoid thickness. The histological analysis of the bone samples showed good trabecular structures and vital cell morphology.