Wachstumsverhalten von humanem, trabekulärem Knochen unter verschiedenen Belastungsbedingungen in einem neuartigen Kultur- und Belastungssystem

The ZETOS system is an ex-vivo culturing und loading system for trabecular bone cores. Cylindrical bone cores (10x5mm) from a human femur head of a 68 year old male patient who had a hip replacement because of a coxarthrosis were cultured over 50 days. Twenty trabecular bone cores were obtained from the femur head. Two samples got lost because of infection. At the beginning three groups were randomly formed. Two grous were loaded with a compression of 2000 and 4000 µstrain for five minutes per day with one Hz. The third group was the non-loaded control group. The applied force while compression was measured simultaneously. To examine bone growth the bone cores were labeled with the fluorescence colouring Calcein and Alizarin red on three days of the study time. Prostaglandin E2 was measured on two days over twelve hours after loading. On the second sample day IL-6, TNF-α and Osteoprotegerin was measured to examine local regulation of bone metabolism. A bone growth with an average MAR of 0,59526 µm/day can be seen in all groups, but there was no significant differences between the loaded and the non-loaded groups. Osteoid and active bone surface was significant increased in the loaded groups. One hour after loading there was a significant increase of Prostaglandin E2, IL-6 and TNF-α within the loading groups. The vitality of the bone cores can be seen in the active bone metabolism, as building osteoid, increasing active bone surface and producing zytokines like Pg-E2, IL-6 and TNF-α. Mechanical loading seems to induce bone remodeling. Increased Osteoid and active bone surface are signs of bone formation, but increased levels of IL-6 and TNF-α are inducing osteoclasts and bone resorption. The exact compression could not be calculated because of calibration differences within the loading system. The E-Modul could not be calculated. The measured forces applied while compression showed a physiological loading of the bone cores, compared to the forces applied to an in-vivo human femur head. The development of the system and the examination of different loading and culture conditions is the issue of further studies.