Microbiomechanical studies on biological tissue/cell interaction and remodeling

1.生长、成熟及血压和血流变化对血管壁重建的影响取自8~周龄的Wistar大鼠颈总动脉，进行生物力学、形态学和组织学研究。血流量、压力、壁厚和壁周弹性模数随年龄增加而增加，但结缔组织的成分保持不变。DOCA-盐性高血压使室壁厚度增加以维持室壁应力恒定，并伴有血管弹性模量值和血管收缩力增加，并伴随着平滑肌细胞肥大。静脉壁也有类似的现象。高血压状态下血流变化不影响室壁切应力。这些变化与结缔组织成分的变化无关。胶原蛋白的交联与衰老和高血压引起的室壁力学性质的变化有一定的关系。2.生长发育成熟和应激剥夺及Re…的影响成熟兔膝关节造成宽度为髌腱宽度的1/3的长方形创面后，应用应力遮挡技术去除愈合过程中的应力。应力剥夺大大抑制和延缓了在缺损区再生的组织的强度增加，也明显降低了残留组织的强度。应力屏蔽后的修复迅速增加了两种组织的强度，尽管IIT即使在很长一段时间后也没有恢复到正常水平，这意味着应力屏蔽对愈合组织产生了非常不利的影响。3.活性变化对松质骨结构和力学性能的影响固定后松质骨的数量和硬度显著降低，但需要较长的时间才能恢复。体育锻炼使松质骨和皮质骨的硬度增加，停止运动后松质骨的硬度恢复正常的速度更快。4.细胞的力学性能研究发展了细胞力学性能测定的新技术。较少

1.Effects of Growth, Maturation, and Blood Pressure and Flow Change on Vascular Wall RemodelingCommon carotid arteries harvested from Wistar rats aged 8 to 64 weeks were used for biomechanical, morphological, and histological studies. Blood flow, pressure, wall thickness, and wall circumferential elastic modulus increased with age ; however, the composition of connective tissues remained unchanged. DOCA-salt hypertension increased wall thickness so as to maintain wall stress at constant, and increased elastic modulus and vascular contractility being accompanied with smooth muscle cell hypertrophy. Similar phenomena were also observed in venous wall. Blood flow changes under hypertension did not affect wall shear stress. These changes did not correlate with the changes in connective tissue composition. Collagen cross-linking has some relation with the changes of wall mechanical properties induced by aging and hypertension.2.Effects of Growth and Maturation, and Stress Deprivation and Re … More stressing on the Mechanical Properties of Healing Patellar TendonsA rectangular defect having the width of 1/3 of the width of the patellar tendon was made in the mature rabbit knee, and then a stress shielding technique was applied to the tendon for removing stress during healing. Stress deprivation greatly suppressed and delayed the increase of strength of the tissue regenerated in the defect and also markedly reduced the strength of the residual tissue. Restressing after stress shielding rapidly increased the strength of both tissues, although iit was not recovered to normal level even after a prolonged period of time, implying that stress shielding gives very adverse effects on healing tissues. Effects of growth factors on tissue healing and mechanical properties of collagen fascicles were also studied.3.Effects of Activity Changes on the Structure and Mechanical Properties of Cancellous BoneThe amount and hardness of cancellous bone were significantly reduced by immobilization ; they were recovered by remobilization, although it took much time. Physical exercise increased the hardness of cancellous and cortical bone, and its quitting returned the hardness to normal more quickly in cancellous bone.4.Mechanical Properties of CellsNew techniques were developed for the determination of the mechanical properties of cells. Less