基于兔肛管直肠角有限元节点探讨直肠黏膜内脱垂型排便困难发生机制

Approach to mechanism of IRP type dysdefecation based on finite element node of anorectal angle of rabbit

目的:基于兔肛门直肠有限元模型,通过测算兔粪块通过肛管直肠角时力学指标的变化,探讨直肠黏膜内脱垂(IRP)发生排便困难的可能机制,为临床治疗提供实验依据。方法:30只新西兰白兔按随机数表法分为空白组、模型组与治疗组,每组各10只。参照课题组前期成功研制的兔IRP模型进行造模;治疗组造模后予消痔灵注射术。各组饲养10天后收集直肠标本,建立不同力学状态的兔肛门直肠有限元模型,比较组间直肠黏膜层与黏膜下层的弹性模量、肛管直肠角平面不同节点的黏膜位移量。结果:直肠黏膜层与黏膜下层的弹性模量变化比较:治疗组﹥空白组﹥模型组;黏膜位移量变化比较(除663节点粪块第一层空白组与治疗组间无统计学差异):模型组﹥空白组﹥治疗组;差异均有统计学意义(P﹤0.05)。结论:直肠组织的弹性模量在IRP型排便困难发生机制中可能起重要作用,表现为在IRP兔肛管直肠角平面,粪块通过时阻力增大,消痔灵注射治疗后其阻力下降。

Objective:Based on the finite element model of rabbit's anorectum,to approach the possible mechanism of IRP-caused dysdefecation by measuring the changes of mechanical indexes of rabbit's feces mass passing through the anorectal angle,so as to provide experimental basis for clinical treatment.Methods:30 white rabbits of New Zealand were randomly divided into blank group,model group and treatment group.The model was established according to the rabbit's IRP model which was successfully developed in the early stage by the research group.The treatment group was injected Xiaozhiling after modeling.Rectal specimens were collected after each group was fed for 10 days.The finite element models of rabbits'anorectum with different mechanical states were established.The elastic moduli of rectal mucosal membrane and submucosa and the displacement of mucous membrane at different nodes of anorectal angle plane were compared among groups.Results:The changes of elastic moduli of rectal mucosal membrane and submucosa were compared,the result was as follows:treatment group﹥blank group﹥model group;while the changes of displacement of mucous membrane were compared,the result was as follows:(Faeces mass passing through the first layer,except 663 nodes,there was no statistical difference between blank group and treatment group)model group﹥blank group﹥treatment group;and the differences were statistically significant(P﹤0.05).Conclusion:The elastic modulus of rectal tissue may play an important role in the mechanism of IRP type dysdefecation,which is manifested as:the resistance increases when the feces mass passes through the anorectal angle plane of IRP rabbits;while this resistance decreases after treatment by injecting Xiaozhiling.