Observation of tissue-engineered changes in osteoporotic functional segment unit with in-vitro load: A preliminary study

To perform mechanobiological analysis about degenerative disc disease through osteoporotic functional segment unit (FSU) cultured in Biomechanical Lumbar Control System (BLCS), various types (compression or complex load) of physiologic mechanical forces were applied to in a controlled manner. The compression and shear load actuator were arranged vertically and horizontally, respectively, to control the complex load. The specimens (vertebral bodies) were scanned to investigate the morphological characteristics before culturing (0 week) and one week after culturing in BLCS by using high resolution in-vivo micro-computed tomography (micro-CT). Also, we implemented the histological method (H&E and Safranin-O staining) to observe the histomorphological changes of the intervertebral disc. The results for morphological characteristics showed that BV/TV, Tb.Th, Tb.Sp, Tb.N and SMI in compression loading group were almost not changed, compared with those of control group. However, BV/ TV, Tb.Th, Tb.N of complex loading group increased more than those of control group, and the contrary tendencies were represented in Tb.Sp and SMI. In the histological method, nucleus pulposus of compression loading group was so depressed that only central part was remained, therefore we could confirm that disc degeneration was considerably progressed. Also, complex loading group and control group had similar morphological changes in the nucleus pulposus parts. Trabecular bone volume didn't increased and disc degeneration was accelerated in only compression loading condition group. It means that there was no more progress of disc degeneration. In this study, we tested compression and shear loading condition of everyday life applied to osteoporotic FSU by BLCS.