Name: 作者聚焦：增进对与年龄相关的晶状体僵硬变化的理解
Uploaded: 2024-04-05T13:00:00
Description: Watch this Scientific Journal Video about Advancing Understanding of Age-Related Lens Stiffness Changes at JoVE.com

由美国国立卫生研究院资助 R01 EY035278 （MR） 支持。

猪的眼睛是从当地的屠宰场获得的。不需要伦理委员会的批准。
1.晶状体解剖（图1）
<ol><li>从猪眼中去除所有周围组织，从巩膜中去除多余的肉，直到只剩下视神经。使用弯曲的镊子和小解剖剪刀完成此过程。在解剖过程中使用神经作为锚来固定眼睛。</li>
	<li>使用手术刀在角膜缘做一个短的圆周切口，然后在赤道处再做一个...

自动压缩猪晶状体的生物力学表征

<ol>
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H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+measurement+of+age-related+stiffening+in+the+crystalline+lens+by+Brillouin+optical+microscopy.">In vivo measurement of age-related stiffening in the crystalline lens by Brillouin optical microscopy.</a> Biophys J. 101 (6), 1539-1545 (2011).</li><li>Weeber, H. A., Gabriele, E., Wolfgang, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stiffness+gradient+in+the+crystalline+lens.">Stiffness gradient in the crystalline lens.</a> Graefes Arch Clin Exp Ophthalmol. 245 (9), 1357-1366 (2007).</li><li>Reilly, M. A., Ravi, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microindentation+of+the+young+porcine+ocular+lens.">Microindentation of the young porcine ocular lens.</a> J Biomech Eng. 131 (4), 044502 (2009).</li><li>Gu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Connexin+50+and+AQP0+are+essential+in+maintaining+organization+and+integrity+of+lens+fibers.">Connexin 50 and AQP0 are essential in maintaining organization and integrity of lens fibers.</a> Invest Ophthalmol Vis Sci. 60 (12), 4021-4032 (2019).</li><li>Sharma, P. K., Busscher, H. J., Terwee, T., Koopmans, S. A., van Kooten, T. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparative+study+on+the+viscoelastic+properties+of+human+and+animal+lenses.">A comparative study on the viscoelastic properties of human and animal lenses.</a> Exp Eye Res. 93 (5), 681-688 (2011).</li><li>Cheng, C., Gokhin, D. S., Nowak, R. B., Fowler, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sequential+application+of+glass+coverslips+to+assess+the+compressive+stiffness+of+the+mouse+lens:+strain+and+morphometric+analyses.">Sequential application of glass coverslips to assess the compressive stiffness of the mouse lens: strain and morphometric analyses.</a> J Vis Exp. (111), e53986 (2016).</li><li>Baradia, H., Negin, N., Adrian, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+lens+stiffness+measurements.">Mouse lens stiffness measurements.</a> Exp Eye Res. 91 (2), 300-307 (2010).</li><li>Reilly, M. A., Cleaver, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inverse+elastographic+method+for+analyzing+the+ocular+lens+compression+test.">Inverse elastographic method for analyzing the ocular lens compression test.</a> J Innov Opt Health Sci. 10 (06), 1742009 (2017).</li><li>Hahn, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+ex+vivo+porcine+lens+shape+during+simulated+accommodation,+before+and+after+fs-laser+treatment.">Measurement of ex vivo porcine lens shape during simulated accommodation, before and after fs-laser treatment.</a> Invest Ophthalmol Vis Sci. 56 (9), 5332-5343 (2015).</li><li>Parreno, J., Cheng, C., Nowak, R. B., Fowler, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effects+of+mechanical+strain+on+mouse+eye+lens+capsule+and+cellular+microstructure.">The effects of mechanical strain on mouse eye lens capsule and cellular microstructure.</a> Mol Biol Cell. 29 (16), 1963-1974 (2018).</li><li>Yoon, S., Aglyamov, S., Karpiouk, A., Emelianov, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mechanical+properties+of+ex+vivo+bovine+and+porcine+crystalline+lenses:+age-related+changes+and+location-dependent+variations.">The mechanical properties of ex vivo bovine and porcine crystalline lenses: age-related changes and location-dependent variations.</a> Ultrasound Med Biol. 39 (6), 1120-1127 (2013).</li><li>Reilly, M. A., Hamilton, P., Gavin, P., Nathan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+behavior+of+natural+and+refilled+porcine+lenses+in+a+robotic+lens+stretcher.">Comparison of the behavior of natural and refilled porcine lenses in a robotic lens stretcher.</a> Exp Eye Res. 88 (3), 483-494 (2009).</li><li>Mekonnen, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+lens+capsule+significantly+affects+the+viscoelastic+properties+of+the+lens+as+quantified+by+optical+coherence+elastography.">The lens capsule significantly affects the viscoelastic properties of the lens as quantified by optical coherence elastography.</a> Front Bioeng Biotechnol. 11, 1134086 (2023).</li><li>Wilde, G. S., Burd, H. J., Judge, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shear+modulus+data+for+the+human+lens+determined+from+a+spinning+lens+test.">Shear modulus data for the human lens determined from a spinning lens test.</a> Exp Eye Res. 97 (1), 36-48 (2012).</li></ol>

镜片压缩是一种用于估计镜片刚度的通用方法。上述程序允许比较不同物种和不同尺寸的镜片。所有变形都根据透镜尺寸进行归一化，弹性模量的计算大致考虑透镜尺寸。有效模量远高于之前报道的猪透镜4、7、11、19 的模量，至少部分原因是使用了厚度而不是曲率半径：猪透镜的极曲半径明显大于厚...

晶状体是眼睛中发现的透明且灵活的器官，它可以通过改变屈光度来聚焦在不同的距离上。这种能力被称为适应。由于睫状肌的收缩和松弛，屈光力会改变。当睫状肌收缩时，晶状体增厚并向前移动，增加其屈光力1,2。屈光率的增加使镜头能够聚焦在附近的物体上。随着人类年龄的增长，晶状体会变得更硬，这种适应能力会逐渐丧失;这种情况被称为老花眼。变硬的机制仍然未知，至少部分原因是与晶状体的生物力学表征相关的困难。
已经采用了多种方法来估计晶状体刚度和生物力学性能。这些方法包括透镜旋转3,4,5，声学方法6,7,8，光学方法，如布里渊显微镜9，压痕10,11和压缩12,13。压缩是最容易获得的实验技术，因为它可以使用简单的仪器（例如，玻璃盖玻片14,15）或单个电动载物台进行。我们之前已经展示了如何从压缩测试中严格估计晶状体的生物力学特性16.这个过程在技术上具有挑战性，需要专门的软件，而对相对刚度测量感兴趣的镜头研究人员不容易使用。因此，在本研究中，我们专注于在考虑透镜尺寸的同时估计透镜弹性模量的可用方法。弹性模量是与其变形性相关的固有材料特性：高弹性模量对应于较硬的材料。
该测试本身是平行板压缩测试，因此可以在合适的商业机械测试系统上进行。在这里，构建了一个由电机、线性平台、运动控制器、称重传感器和放大器组成的定制仪器。这些都是使用定制软件控制的，该软件还定期记录时间、位置和负载。猪镜片不适应，但易于获得且价格低廉17.开发了以下方法来逐步压缩眼睛晶状体并量化其弹性模量。这种方法可以很容易地复制，并且在晶状体刚度的研究中很有用。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Curved Medium Point General Purpose Forceps</td>
			<td>Fisherbrand</td>
			<td>16-100-110</td>
			<td></td>
		</tr>
		<tr>
			<td>Galil COM Libraries</td>
			<td>Galil Motion Control</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>High Precision Scalpel Handle&#160;</td>
			<td>Fisherbrand</td>
			<td>12-000-164</td>
			<td></td>
		</tr>
		<tr>
			<td>Linear Stage</td>
			<td>McMaster-Carr</td>
			<td>6734K4 0.125&#34;</td>
			<td></td>
		</tr>
		<tr>
			<td>Load Cell</td>
			<td>FUTEK</td>
			<td>LSB200-FSH03869</td>
			<td></td>
		</tr>
		<tr>
			<td>Load Cell Amplifier</td>
			<td>FUTEK</td>
			<td>IAA300-FSH03931</td>
			<td></td>
		</tr>
		<tr>
			<td>MATLAB</td>
			<td>The Mathworks, Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microprobe</td>
			<td>Surgical Design&#160;</td>
			<td>22-079-740</td>
			<td></td>
		</tr>
		<tr>
			<td>Miniature Self Opening Precision Scissors&#160;</td>
			<td>Excelta&#160;</td>
			<td>63042-004</td>
			<td></td>
		</tr>
		<tr>
			<td>Motion Controller</td>
			<td>Galil Motion Control</td>
			<td>DMC-31012</td>
			<td></td>
		</tr>
		<tr>
			<td>Motor</td>
			<td>Galil Motion Control</td>
			<td>BLM-N23-50-1000-B</td>
			<td></td>
		</tr>
		<tr>
			<td>Straight Hemastats&#160;</td>
			<td>Fine Science&#160;</td>
			<td>NC9247203</td>
			<td>stainless steel, 14cm&#160;</td>
		</tr>
	</tbody>
</table>

automated compression testing of the ocular lens

人工晶状体的生物力学特性对于其作为可变功率光学元件的功能至关重要。这些特性随着人类晶状体年龄的增长而发生巨大变化，导致近视力丧失，称为老花眼。然而，这些变化的机制仍然未知。晶状体压缩提供了一种相对简单的方法，用于定性地评估晶状体的生物力学刚度，并且当与适当的分析技术相结合时，可以帮助量化生物力学特性。迄今为止，已经进行了各种镜片压缩测试，包括手动和自动，但这些方法应用生物力学测试的关键方面不一致，例如预处理、加载速率和测量间隔时间。本文描述了一种全自动镜头压缩测试，其中电动载物台与相机同步，以在整个预编程的加载协议中捕获镜头的力、位移和形状。然后可以从这些数据中计算出特征弹性模量。虽然这里使用猪镜片进行演示，但该方法适用于任何物种的镜片压缩。

The lens is the transparent and flexible organ found in the eye that allows it to focus on different distances by changing its refractive power. This ability is known as accommodation. The refractive power is altered due to the contraction and relaxation of the ciliary muscle. When the ciliary muscle contracts, the lens thickens and moves forward, increasing its refractive power1,2. The increase in refractive power allows the lens to focus on nearby objects. As humans age, the lens becomes stiffer and this ability to accommodate is gradually lost; this condition is known as presbyopia. The mechanism of stiffening remains unknown, at least in part due to the difficulties associated with the biomechanical characterization of the lens.
A variety of methods have been employed to estimate lens stiffness and biomechanical properties. These include lens spinning3,4,5, acoustic methods6,7,8, optical methods such as Brillouin microscopy9, indentation10,11, and compression12,13. Compression is the most accessible experimental technique as it can be performed with simple instrumentation (e.g., glass coverslips14,15) or a single motorized stage. We have previously shown how the biomechanical properties of the lens may be rigorously estimated from a compression test16. This process is technically challenging and requires specialized software not readily accessible to lens researchers interested in relative stiffness measurements. Therefore, in the present study, we focus on accessible methods for estimating the elastic modulus of the lens while accounting for lens size. The elastic modulus is an intrinsic material property related to its deformability: a high elastic modulus corresponds to a stiffer material.
The test itself is a parallel plate compression test and can therefore be performed on suitable commercial mechanical testing systems. Here, a custom instrument was constructed comprised of a motor, linear stage, motion controller, load cell, and amplifier. These were controlled using custom software which also recorded time, position, and load at regular intervals. Pig lenses do not accommodate but are easily accessible and inexpensive17. The following method was developed to incrementally compress the eye lens and quantify its elastic modulus. This method can be easily replicated and will be useful in the study of lens stiffness.

作者聚焦：增进对与年龄相关的晶状体僵硬变化的理解 

人工晶状体的自动压缩测试

We're trying to understand how people lose their near vision with age. We know that this is due, in part, to a change in lens stiffness, but we still don't know why the lens stiffens as we age. Current experimental methods rely on crude methods for loading the lens, such as placing microscope cover slips on the lens.These methods are tedious and lack appropriate controls for the rate of loading. We have determined that the lens shape is the primary driver of presbyopia, and we know that the shape is primarily driven by biomechanical parameters. This protocol offers a completely objective, reproducible method for measuring lens stiffness.Automation allows us to control the rate of loading, which is a key parameter when characterizing a viscoelastic material, like the lens. We now have an objective, repeatable protocol for measuring lens biomechanical properties. This will allow us to rigorously characterize how the lens stiffens with age, as well as how specific proteins modify the lens biomechanical properties.

压缩六个猪晶状体，首先在胶囊完好无损的情况下，然后在小心地取出胶囊后。封装镜片的厚度值分别为 7.65 ± 0.43 mm，解封镜片的厚度值分别为 6.69 ± 0.29 mm（平均值±标准差）。典型的加载历史记录如 图 3 所示。赫兹模型很好地拟合了由此产生的力-位移曲线（即，它们的力与升至1.5次方的位移成正比; 图4）。封装和解封膜透镜都是如此。
<p class="j...

Watch this Scientific Journal Video about Advancing Understanding of Age-Related Lens Stiffness Changes at JoVE.com

我们提出了一种使用压缩测试表征人工晶状体有效弹性模量的自动化方法。

The biomechanical properties of the ocular lens are essential to its function as a variable power optical element. These properties change dramatically ...

我们试图了解人们如何随着年龄的增长而失去近视力。我们知道这在一定程度上是由于晶状体刚度的变化，但我们仍然不知道为什么晶状体会随着年龄的增长而变硬。目前的实验方法依赖于粗略的方法来加载镜头，例如在镜头上放置显微镜盖玻片。这些方法很繁琐，并且缺乏对加载速率的适当控制。我们已经确定晶状体形状是老花眼的主要驱动因素，并且我们知道形状主要由生物力学参数驱动。该协议为测量透镜刚度提供了一种完全客观、可重复的方法。自动化使我们能够控制加载速率，这是表征粘弹性材料（如透镜）时的关键参数。我们现在有一个客观的、可重复的协议来测量晶状体的生物力学特性。这将使我们能够严格表征晶状体如何随着年龄的增长而变硬，以及特定蛋白质如何改变晶状体的生物力学特性。

automated-compression-testing-of-the-ocular-lens

Research

JoVE Journal

Bioengineering

Automated Compression Testing of the Ocular Lens

The biomechanical properties of the ocular lens are essential to its function as a variable power optical element. These properties change dramatically with age in the human lens, resulting in a loss of near vision called presbyopia. However, the mechanisms of these changes remain unknown. Lens compression offers a relatively simple method for assessing the lens' biomechanical stiffness in a qualitative sense and, when coupled with appropriate analytical techniques, can help quantify biomechanical properties. A variety of lens compression tests have been performed to date, including both manual and automated, but these methods inconsistently apply key aspects of biomechanical testing such as preconditioning, loading rates, and time between measurements. This paper describes a fully automated lens compression test wherein a motorized stage is synchronized with a camera to capture the force, displacement, and shape of the lens throughout a preprogrammed loading protocol. A characteristic elastic modulus may then be calculated from these data. While demonstrated here using porcine lenses, the approach is appropriate for the compression of lenses of any species.

We present an automated method for characterizing the effective elastic modulus of an ocular lens using a compression test.