Effects of compressive loading on biomechanical properties of disc and peripheral tissue in a rat tail model

Abstract

Intervertebral disc degeneration induced by mechanical compression is an important issue in spinal disorder research. In this study, the biomechanical aspect of the rat tail model was investigated. An external loading device equipped with super-elastic TiNi springs was developed to apply a precise load to the rat tail. By using this device, rat tail discs were subjected to compressive stress of 0.5 or 1.0 MPa for 2 weeks. Discs in the sham group received an attachment of the device but no loading. After the experimental period, first the intact tail with peripheral tissues (PT) such as tendon and skin and then the retrieved disc without PT were subjected to a uniaxial tension-compression test; biomechanical characteristics such as range of motion (ROM), neutral zone (NZ), and hysteresis loss (HL) were evaluated. Furthermore, the loadbearing contribution of PT in the intact tail was estimated by comparing the load-displacement curves obtained by the mechanical tests performed with and without PT. The experimental findings revealed that the continuous compressive stress induced reduction in disc thickness. The intact tail demonstrated decreases in ROM and NZ as well as increases in HL. On the other hand, the retrieved disc demonstrated increases in ROM, NZ, and HL. Further, a significant increase in the load-bearing contribution of PT was indicated. These findings suggest that the load-bearing capacity of the disc was seriously deteriorated by the application of compressive stress of 0.5 or 1.0 MPa for 2 weeks.

Intervertebral disc changes with angulation, compression and reduced mobility simulating altered mechanical environment in scoliosis

“…Stiffness changes in discs subjected to compressive loading in vivo were thought to be due to stiffening of tissues surrounding the disc (longitudinal ligaments, tendons, muscle, skin), rather than disc tissue [21], suggesting that the inconsistent findings (increased stiffness only in Groups B and R, and large variability between animals in each group) may be related to variability in the amount of tissue surrounding the discs that was removed. It was reported that there was no change in mechanical lateral bending stiffness in the segment of the mouse tail subjected to static in vivo bending [7].…”

Impact of Dynamic and Static Load on Bone Around Implants: An Experimental Study in a Rat Model

“…The devices 10,13 for static loading were prepared by mounting four 0.98-N super elastic springs (TOMY), as shown in Fig 1. The two implants were connected to each other at both sides, which allowed a continuous static load of 3.92 N to be exerted.…”

“…An electromagnetic microtester (MMT-250N Shimadzu) was also used. For the dynamic load experiment, 10,13 each implant was fixed to the device for 10 minutes each day, as shown in Fig 2, and the actuator was used to apply the load to the implant. This loading was performed 5 days per week, over a total of 4 weeks.…”

Mechanism of the Mitogen-Activated Protein Kinases/Mammalian Target of Rapamycin Pathway in the Process of Cartilage Endplate Stem Cell Degeneration Induced by Tension Load

“… 8 , 9 Tension load (TL) contributes a lot to the initiation and progression of IVDD. 10 , 11 Therefore, the in-depth study of the specific mechanism of TL-induced CESCs degeneration is of great significance for the early prevention and treatment of IVDD.…”