背景:本研究的目的是研究四种不同剂量的维拉帕米对2型糖尿病大鼠股骨远端松质骨在动态外载荷作用下的力学行为和流体流动特性的影响。
方法:基于显微CT图像,对照组大鼠股骨远端松质骨和液体的有限元模型,糖尿病组,治疗组VER4,VER12,VER24和VER48(维拉帕米剂量为4,12,24和48mg/kg/天,分别)建造。将振幅为0.8μm,周期为1s的正弦时变位移载荷施加到固体区域的上表面。然后,采用流固耦合数值模拟方法分析了VonMises应力的大小和分布,流速,各组松质骨模型的流体剪切应力。
结果:vonMises应力平均值的结果,流速和FSS(t=0.25s)如下:对照组的值低于糖尿病组;这三个参数随维拉帕米的剂量而变化;在四个治疗组中,VER48组的值最低,他们是最接近对照组的,它们比糖尿病组小。在四个治疗组中,VER48组在松质骨表面FSS=1-3Pa的结节比例最高,VER48组的更多区域承受1-3Pa的流体剪切应力超过一半的时间。
结论:可以看出,在四个治疗组中,最高剂量组(VER48组)松质骨表面的成骨细胞更容易被机械载荷激活,治疗效果最好。这项研究可能有助于了解维拉帕米对2型糖尿病骨的作用机制。为临床治疗2型糖尿病时维拉帕米剂量的选择提供理论指导。
BACKGROUND: The purpose of this study was to investigate the effects of four different doses of
verapamil on the mechanical behaviors of solid and the characteristics of fluid flow in cancellous bone of distal femur of type 2 diabetes rats under dynamic external load.
METHODS: Based on the micro-CT images, the finite element models of cancellous bones and fluids at distal femurs of rats in control group, diabetes group, treatment groups VER 4, VER 12, VER 24, and VER 48 (
verapamil doses of 4, 12, 24, and 48 mg/kg/day, respectively) were constructed. A sinusoidal time-varying displacement load with an amplitude of 0.8 μm and a period of 1s was applied to the upper surface of the solid region. Then, fluid-solid coupling numerical simulation method was used to analyze the magnitudes and distributions of von Mises stress, flow velocity, and fluid shear stress of cancellous bone models in each group.
RESULTS: The results for mean values of von Mises stress, flow velocity and FSS (t = 0.25s) were as follows: their values in control group were lower than those in diabetes group; the three parameters varied with the dose of
verapamil; in the four treatment groups, the values of VER 48 group were the lowest, they were the closest to control group, and they were smaller than diabetes group. Among the four treatment groups, VER 48 group had the highest proportion of the nodes with FSS = 1-3 Pa on the surface of cancellous bone, and more areas in VER 48 group were subjected to fluid shear stress of 1-3 Pa for more than half of the time.
CONCLUSIONS: It could be seen that among the four treatment groups, osteoblasts on the cancellous bone surface in the highest dose group (VER 48 group) were more easily activated by mechanical loading, and the treatment effect was the best. This study might help in understanding the mechanism of
verapamil\'s effect on the bone of type 2 diabetes mellitus, and provide theoretical guidance for the selection of
verapamil dose in the clinical treatment of type 2 diabetes mellitus.