Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, Illinois, United States of America.
PLoS One. 2020 Feb 21;15(2):e0227856. doi: 10.1371/journal.pone.0227856. eCollection 2020.
Despite the significant progress in characterizing mechanical functions of individual scleral extracellular matrix (ECM) components, the biomechanical contribution of sulfated glycosaminoglycans (sGAGs) is still poorly understood. The primary purpose of this study was to determine the possible function of sGAGs in scleral mechanical response by characterizing the tensile behavior of normal and sGAG-depleted samples. We used chondroitinase ABC solution to remove sGAGs from scleral samples that were dissected from posterior porcine eyes. We performed biochemical analyses for assessing the efficacy of sGAG removal protocol. Furthermore, we conducted stress-controlled uniaxial tensile tests to characterize the influence of sGAG removal on mechanical properties of sclera. The tensile behavior of scleral strips right after dissection and after being soaked in buffer was also determined. Biochemical analyses confirmed that 18 hour incubation in 0.125 U/ml Chondroitinase ABC solution removed over 90% of chondroitin and dermatan sGAGs. No significant difference was observed in the thickness/hydration of samples because of enzyme- and buffer-treated samples. Furthermore, it was found that sGAG depletion did not significantly alter the tangent modulus, energy dissipation, and peak strain of posterior scleral strips. It was concluded that sGAGs did not influence the stress-controlled viscoelastic tensile response of sclera.
尽管在表征单个巩膜细胞外基质（ECM）成分的机械功能方面取得了重大进展，但硫酸化糖胺聚糖（sGAG）的生物力学贡献仍知之甚少。本研究的主要目的是通过表征正常和 sGAG 耗尽样品的拉伸行为，确定 sGAG 在巩膜机械响应中的可能功能。我们使用软骨素酶 ABC 溶液从从猪眼后段分离的巩膜样本中去除 sGAG。我们进行了生化分析，以评估 sGAG 去除方案的效果。此外，我们进行了应力控制的单轴拉伸试验，以表征 sGAG 去除对巩膜机械性能的影响。还测定了巩膜条在解剖后和在缓冲液中浸泡后的拉伸行为。生化分析证实，在 0.125 U/ml 软骨素酶 ABC 溶液中孵育 18 小时可去除超过 90%的软骨素和真皮素 sGAG。由于酶和缓冲液处理的样品，样品的厚度/水合作用没有明显差异。此外，发现 sGAG 耗尽并没有显著改变后巩膜条的切向模量、能量耗散和峰值应变。结论是 sGAG 不会影响巩膜的应力控制粘弹性拉伸响应。
