Experimental myopia increases and scleral crosslinking using genipin inhibits cyclic softening in the tree shrew sclera.
Experimental myopia increases and scleral crosslinking using genipin inhibits cyclic softening in the tree shrew sclera.
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DOI：
10.1111/opo.12454
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发表时间：
2018-05
期刊：
影响因子：
--
通讯作者：
Grytz R
中科院分区：
文献类型：
--
作者：
Levy AM;Fazio MA;Grytz R
近视进展被认为涉及巩膜的生物力学减弱，这会导致不可逆转的变形和眼轴延长。巩膜交联术已被提出作为一种潜在的治疗方案，通过加强机械削弱的巩膜来控制近视。近视期间巩膜变弱，而交联术后巩膜变强的生物力学机制尚不完全清楚。在这里，我们评估了晶状体诱导近视和使用京尼平的外源性交联剂对树鼠巩膜循环拉伸试验测量的非弹性力学性能的影响。在生理载荷条件下(50周期，0~3.3g，30s/周期)对2 mm宽的巩膜条进行循环拉伸试验。在正常和配戴单眼−5-D晶状体4天后，幼龄树鼠每只眼获得两条巩膜条带，以加速巩膜重塑和诱导近视。分别在摘除即刻、37℃磷酸盐缓冲液(PBS)孵育24小时和低浓度(0.25 mM)含金尼平的PBS孵育24小时后，对巩膜条进行力学测试。循环软化被定义为从一个循环到下一个循环的增量应变增加。与对侧对照眼相比，−5D晶状体治疗后巩膜周期性软化反应显著增加(0.1±0.029，平均±标准差，p=0.037)。经晶状体处理的巩膜外源性交联剂显著降低循环软化反应(−0.12±0.014，p=2.2×10−5)。与所有其他组相反，在50个周期的测试中，京尼平交联的组织没有表现出明显不同于零的周期软化。结果表明，循环拉伸载荷导致幼龄树鼠巩膜发生非弹性循环软化。晶状体诱导近视时软化率增加，经京尼平交联剂处理后软化率降低。这一发现表明，近视眼的眼轴延长可能涉及一种生物力学减弱机制，该机制增强了巩膜的循环软化反应，而巩膜交联剂京尼平则抑制了这种反应。
Myopia progression is thought to involve biomechanical weakening of the sclera, which leads to irreversible deformations and axial elongation of the eye. Scleral crosslinking has been proposed as a potential treatment option for myopia control by strengthening the mechanically weakened sclera. The biomechanical mechanism by which the sclera weakens during myopia and strengthens after crosslinking is not fully understood. Here, we assess the effect of lens-induced myopia and exogenous crosslinking using genipin on the inelastic mechanical properties of the tree shrew sclera measured by cyclic tensile tests. Cyclic tensile tests were performed on 2-mm wide scleral strips at physiological loading conditions (50 cycles, 0–3.3 g, 30 sec/cycle). Two scleral strips were obtained from each eye of juvenile tree shrews exposed to two different visual conditions: normal and 4 days of monocular −5 D lens wear to accelerate scleral remodeling and induce myopia. Scleral strips were mechanically tested at three alternative conditions: immediately after enucleation; after incubation in phosphate buffered saline (PBS) for 24 hours at 37°C; and after incubation for 24 hours in PBS supplemented with genipin at a low cytotoxicity concentration (0.25 mM). Cyclic softening was defined as the incremental strain increase from one cycle to the next. −5D lens treatment significantly increased the cyclic softening response of the sclera when compared to contralateral control eyes (0.10 ± 0.029, mean ± standard error, p = 0.037). Exogenous crosslinking of the lens treated sclera significantly decreased the cyclic softening response (−0.12 ± 0.014, p = 2.2×10−5). Contrary to all other groups, the genipin-crosslinked tissue did not exhibit cyclic softening significantly different from zero within the 50-cycle test. Results indicated that cyclic tensile loading leads to an inelastic, cyclic softening of the juvenile tree shrew sclera. The softening rate increased during lens-induced myopia and was diminished after genipin crosslinking. This finding suggests that axial elongation in myopia may involve a biomechanical weakening mechanism that increased the cyclic softening response of the sclera, which was inhibited by scleral crosslinking using genipin.
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影响因子：
2.6
作者：
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