A new article published in the Journal of the Mechanical Behavior of Biomedical Materials used F-CHPs (Figure 7) to assess the damage in an intervertebral disc (IVD) model. Researchers used CHPs to help validate their new mouse disc organ culture system by dynamically applying compression loading in a customized micro-culture device tailored for mouse lumbar discs. They tested native, static, and loaded discs to see how mechanical damage affects disc health. They also evaluated three different regions within the mouse discs to see how each region was influenced by the mechanical stresses.
ABSTRACT: Mechanical loading plays an important role in maintaining disc health and function, and in particular, excessive mechanical loading has been identified as one of major reasons of disc degeneration. Intervertebral disc organ culture serves as a valuable tool to study disc biology/pathology. In this study, we report the development and validation of a new mouse disc organ culture system by dynamically applying compression loading in a customized micro-culture device tailored for mouse lumbar discs. Precise axial compression force was delivered by a computer-controlled system consisting of a robust micromechanical linear actuator, a force sensitive resistor, and a precision micro-stepping machinery. Customized PDMS-based loading chambers allowed simultaneous loading of six discs per regimen, which streamlined the workflow to reach sufficient statistic power. The detrimental loading regimen of mouse lumbar discs (0.5 MPa of axial compression at 1Hz for 7 days) was demonstrated through live-dead assay, histology, and fluorescence probe based collagen staining. In addition, various mechanical compression profiles were simulated using different materials and geometry designs, potentiating for more sophisticated loading protocols. In summary, we developed a new mechanical loading system for dynamic axial compression of mouse discs, which created a unique avenue to study disc pathogenesis with enriched mouse species-related resources, and complemented the existing spectrum of bioreactor systems predominately for discs of human and large animals.
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