Papers by Keyword: Mechanical Stimulation

Abstract: To understand the effect of mechanical stimulation on posterior sclera reinforcement (PSR), the rabbit scleral fibroblasts after PSR were subjected to stretch in vitro and MMP-2 and TIMP-2 expression of scleral fibroblasts were evaluated. Three-week-old rabbits were monocularly performed by eyelid suturation randomly to prepare experimental myopia eye. After 60 days, the experimental myopia eyes were treated by PSR. After 6 months, the posterior pole scleral fibroblasts (normal sclera - group A, sclera after operation - group B and fusion region of sclera and reinforcing band group C) were isolated and cultured in vitro. The cells were subjected to cyclic stretch regimens (sine wave, 3% and 6% elongation amplitude, 0.1Hz, 48h duration) by FX-4000 Tension System. The MMP-2 and TIMP-2 expression of scleral fibroblasts were evaluated by ELISA method. The results show that after cyclic stretch to the scleral fibroblasts of the normal sclera and the sclera after operation, the MMP-2 expression was significantly reduced and the TIMP-2 expression was significantly increased, the MMP-2 and TIMP-2 expression of the scleral fibroblasts of the fusion region after operation was no changed. It was indicated that the mechanical stimulation could regulate the MMP-2 and TIMP-2 expression of scleral fibroblasts and play an important role in the process of treating high myopia with PSR surgery.

Abstract: The mechanical stimulation can affect the biological function of lung cells, but little is known about the effects on biomechanical properties of lung fibroblasts. In this paper, the human lung fibroblasts (MRC-5) were subjected to cyclic stretch (5% and 10% elongation amplitude) by FX-4000 Tension System. The micropipette aspiration technique was used to investigate the viscoelasticity of MRC-5. The results: for 5% stretch group, the viscoelastic parameters of MRC-5 were significantly lower than static group at 72 h; for 10% stretch group, the viscoelastic parameters of MRC-5 were significantly lower than static group at 48 h and 72 h, there was no difference of the viscoelastic parameters between 48 h and 72 h. The changes of viscoelasticity suggest that the lung fibroblast have different response to different mechanical stimulation and the mechanical stimulation plays an important role in regulating the viscoelasticity in the process of the growth and development.

Abstract: A bioreactor has provided a new way for the biomedical tissue engineering, and it is a device system that simulates the metabolism and movement of organisms to obtain target product in vitro. By reference and study of the bioreactors, based on the linear motor of high-precision and high-frequency characteristics, we have designed a bioreactor with varieties of biomechanical functions by using CAD design software, that is especially used in the tissue engineering for mechanical stimulation. The bioreactor can not only load on the cultures under rolling, sliding or their combination as well as tension and compression, but also on the cultures under high-frequency and dual-frequency forces. It will provide a more effective research platform for tissue culture and regeneration.

Abstract: To engineer cartilaginous constructs with a mechano-active scaffold and dynamic compression was performed for effective cartilage tissue engineering. Mechano-active scaffolds were fabricated from very elastic poly(L-lactide-co-ε-carprolactone)(5:5). The scaffolds with 85 % porosity and 300~500 μm pore size were prepared by a gel-pressing method. The scaffolds were seeded with chondrocytes and the continuous compressive deformation of 5% strain was applied to cell-polymer constructs with 0.1Hz to evaluate for the effect of dynamic compression for regeneration of cartilage. Also, the chondrocytes-seeded constructs stimulated by the continuous compressive deformation of 5% strain with 0.1Hz for 10 days and 24 days respectively were implanted in nude mice subcutaneously to investigate their biocompatibility and cartilage formation. From biochemical analyses, chondrogenic differentiation was sustained and enhanced significantly and chondrial extracellular matrix was increased through mechanical stimulation. Histological analysis showed that implants stimulated mechanically formed mature and well-developed cartilaginous tissue, as evidenced by chondrocytes within lacunae. Masson’s trichrome and Safranin O staining indicated an abundant accumulation of collagens and GAGs. Also, ECM in constructs was strongly immuno-stained with anti-rabbit collagen type II antibody. Consequently, the periodic application of dynamic compression can improve the quality of cartilaginous tissue formed in vitro and in vivo.