冷冻和解冻对猪眼组织生物力学特性的影响。

Effect of freezing and thawing on the biomechanical characteristics of porcine ocular tissues.

机构信息

School of Engineering, University of Liverpool, Liverpool, UK.

出版信息

J Biomech. 2019 Apr 18;87:93-99. doi: 10.1016/j.jbiomech.2019.02.024. Epub 2019 Mar 1.

DOI:10.1016/j.jbiomech.2019.02.024

PMID:30876736

Abstract

PURPOSE

To evaluate the effect of freezing and thawing on the biomechanical properties of ex-vivo porcine ocular tissue.

METHODS

Thirty-six porcine eyes (18 pairs) were obtained fresh from a local abattoir and split into two groups of nine pairs to study the effect of storage at -20 °C and -80 °C. A randomly-selected eye from each pair (Control Group, CG) was tested fresh while the fellow eyes were frozen for 14 days, either at -20 °C and -80 °C (Frozen Group, FG) before thawing and testing. Seventy-two strips were extracted from the corneas and scleras of eye globes and subjected to uniaxial tension tests under loads up to 1.0 N. Following five preconditioning cycles, the load and elongation data obtained experimentally were analysed to derive the tissue's stress-strain and tangent modulus-strain behaviour.

RESULTS

Corneal tissue subjected to freezing at -20 °C exhibited significant increases in tangent modulus (mechanical stiffness) by 13 ± 17% (p = 0.003) at 1% strain and 14 ± 12% (p < 0.001) at 2% strain. In contrast, the increases in corneal stiffness at -80 °C were insignificant (6 ± 14%, p = 0.099 at 1% strain, 6 ± 15%, p = 0.091 at 2% strain). The corresponding increases in tangent modulus in the sclera were all insignificant (for -20 °C: 4 ± 14%, p = 0.265 at 1% strain, 3 ± 9%, p = 0.186 at 2% strain; for -80 °C: 3 ± 18%, p = 0.537 at 1% strain and 3 ± 18%, p = 0.491 at 2% strain).

CONCLUSIONS

The study provided evidence that freezing and thawing led to insignificant changes in ocular tissue stiffness except in corneal tissue that was frozen at -20 °C.

摘要

目的

评估冷冻和解冻对离体猪眼组织生物力学特性的影响。

方法

从当地屠宰场获得 36 只猪眼（18 对），分为两组，每组 9 对，研究在-20°C 和-80°C 下储存的效果。每对眼睛中的一只（对照组，CG）新鲜测试，而另一只在-20°C 和-80°C 下冷冻 14 天后解冻并测试（冷冻组，FG）。从眼球的角膜和巩膜中提取 72 个条带，并在高达 1.0N 的载荷下进行单轴拉伸测试。经过五个预条件循环后，分析实验获得的载荷和伸长数据，得出组织的应力-应变和正切模量-应变行为。

结果

在-20°C 下冷冻的角膜组织在 1%应变时的正切模量（机械刚度）显著增加 13%±17%（p=0.003），在 2%应变时增加 14%±12%（p<0.001）。相比之下，在-80°C 下冷冻对角膜刚度的增加不显著（1%应变时 6%±14%，p=0.099，2%应变时 6%±15%，p=0.091）。巩膜的正切模量相应增加均不显著（-20°C：1%应变时 4%±14%，p=0.265，2%应变时 3%±9%，p=0.186；-80°C：1%应变时 3%±18%，p=0.537，2%应变时 3%±18%，p=0.491）。