正常兔角膜生物力学特性和参数的测定

背景 研究证实软体生物组织在受力状态下具有稳定的生物力学特性.对于人的眼球来说,全面研究其生物力学特性较为困难,常常受到仪器设备、跨学科知识及材料获得等多因素的影响.兔是眼科学研究的主要动物模型之一,有关正常兔中央角膜的生物力学特性尚不清楚. 目的 了解兔角膜生物力学特性,获得正常兔角膜中央区的生物力学参数.方法 10只清洁级家兔处死后沿角膜缘分离完整的角膜,按照7 mm×5 mm的模具制备20个长方形角膜组织试件,在常温和空气加湿器加湿以模拟活体组织环境下,用BOSE electroforce3220-AT型生物力学试验机进行拉伸破坏试验、应力-应变试验、应力松弛试验和蠕变试验,得到角膜组织的拉伸破坏曲线、应力-应变关系曲线、应力松弛曲线和蠕变曲线,评估兔角膜组织的生物力学参数.结果 兔角膜的最大强度为(7.7432±0.6099) MPa,经过3次循环加载后,应力-应变曲线逐渐平稳.应力随着时间的延长逐渐衰减,前期衰减较快,随着时间的延长曲线趋于平缓,松弛率为30.33％；而角膜试件的形变随时间的延长而逐渐增大,早期形变较快,后期逐渐变缓,蠕变率为24.33％. 结论 揭示了兔角膜生物力学特性,为以后能否用兔眼模型研究人类眼部疾病提供力学指导.

Biomecbanical parameter of normal rabbit cornea

Background It has been proved that, after being forced, the biological soft tissue has stable biomechanical characteristics. However, there is rare study on corneal biomechanics. Rabbit is a main animal for experimental study in ophthalmology. But the biomechanical study of cornea in normal rabbit has not been reported. Objective This study was to investigate the biomechanical properties of normal rabbit central cornea and acquire the parameter. Methods Ten rabbits were sacrificed and the whole corneas were obtained and 20 central cornea specimens with 7 mmx5 mm of rabbit were prepared and tested on BOSE electroforce 3220-AT biomechanics machine under the room temperature and suitable humidity environment. Uniaxial tension, stress between strain, relaxation and creep were performed and the curves were drawn. The data was collected by wintest system to evaluate the biomechanical parameters of rabbit corneal tissue. Results The maximum distortion intension of rabbit cornea was （7. 7432±0. 6099）MPa. After three cyclic loading, the stress gradually attenuated and the stress and strain flattened as the time change with the relaxation rate 30.33%. The deformation of the specimens enhanced with time decrease with the creep rate 24.33%. Conclusions The biomechanical characteristics of normal rabbit cornea are revealed in this study, which offer the basis for the experimental research of rabbit model aimed at corneal disease.