Lens growth

晶状体生长
  • 文章类型: Journal Article
    连接蛋白50(Cx50)介导的信号传导对于控制晶状体生长和大小至关重要。Cx50突变导致小眼症,较小的镜头,人类和动物的白内障。从未通过使用非侵入性成像技术在活的Cx50突变小鼠中研究过这些眼部缺陷。这里,我们报道了一项使用谱域光学相干断层扫描(SD-OCT)对3周至12月龄的Cx50基因敲除(Cx50KO)小鼠眼部缺损的纵向研究.前房深度(ACD),透镜厚度(LT),玻璃体腔深度(VCD),沿视轴测量和轴向长度(AL),并用相应的折射率进行调整。SD-OCT图像数据证实,与年龄匹配的野生型(WT)对照相比,活Cx50KO小鼠中LT和AL的年龄相关性降低。减少值与以前报道的Cx50KO眼球和镜片的体外测量值相当。此外,在所有研究年龄的Cx50KO小鼠中观察到ACD的减少,而与WT对照相比,VCD变化在统计学上不显著.因此,Cx50KO的小眼病与小晶状体选择性地与ACD发育延迟相关,但与玻璃体形成无关。这项工作支持以下观点:晶状体大小和/或生长对前房发育很重要。
    Connexin 50 (Cx50) mediated signaling is essential for controlling the lens growth and size. Cx50 mutations cause microphthalmia, smaller lenses, and cataracts in humans and animals. These ocular defects have never been investigated in live Cx50 mutant mice by using non-invasive imaging techniques. Here, we report a longitudinal study of the ocular defects in Cx50 knockout (Cx50KO) mice from the ages of 3 weeks to 12 months by using spectral-domain optical coherence tomography (SD-OCT). The anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD), and axial length (AL) were measured along the visual axis and adjusted with corresponding refractive indices. The SD-OCT image data confirm age-related reductions of LT and AL in live Cx50KO mice compared to age-matched wild-type (WT) controls, and the reduction values are comparable to the in vitro measurements of Cx50KO eyeballs and lenses reported previously. Moreover, reductions of ACD were observed in Cx50KO mice at all ages studied while VCD changes are statistically insignificant in comparison to the WT controls. Therefore, Cx50KO\'s microphthalmia with small lens is selectively associated with delayed ACD development but not the vitreous formation. This work supports the notion that lens size and/or growth is important for anterior chamber development.
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  • 文章类型: Journal Article
    未经批准:为了研究生长模型,形状,晶状体和眼球的发育关系,我们使用二维磁共振(MR)成像来研究体内选定眼部参数的与年龄相关的变化.
    UNASSIGNED:我们回顾性回顾了126例妊娠21至39周胎儿的MR图像。测量横向平面MR成像的眼部参数,包括晶状体直径(LD),前后晶状体直径(APLD),透镜表面积(LS),球形直径(GD),前后球直径(APGD),地球表面面积(GS)。每个生物特征与胎龄(GA)的生长模型,镜头和球体的纵横比(LD/APLD和GD/APGD),并通过统计分析研究了晶状体与眼球表面积之比(LS/GS)之间的增长关系。
    UNASSIGNED:大多数胎龄生物特征的生长模型是对数的,除了眼球直径(GD和APGD)显示出二次生长模式。我们的研究表明,在21-39周内,晶状体的横向直径始终大于前后直径(P<0.001)。此外,表面积比(LS/GS)随GA变化不显著(P=0.4908),LS的增加与GS的增加显着一致(P<0.001)。
    未经证实:整个胎儿生命中的晶状体形状可能参与该过程,形状从垂直椭圆体改变,球形到横向椭圆体,基于晶状体横向和前后直径的对数增加比率。同时,胎儿晚期的眼球长宽比可能意味着在妊娠期间逐渐呈球形。这项研究的列线图数据可以提供有关胎儿晶状体形态变化以及晶状体与眼球之间同步关系的适当信息。
    UNASSIGNED: To study the growth model, shape, and developmental relationship of lens and eyeball, we used two-dimensional Magnetic Resonance (MR) imaging to investigate gestationally age-related changes in the selected ocular parameters in vivo.
    UNASSIGNED: We retrospectively reviewed the MR images from 126 fetuses ranging from 21 to 39 weeks\' gestation. Ocular parameters on MR imaging of transverse plane were measured including lens diameter (LD), anteroposterior lens diameter (APLD), lens surface area (LS), globe diameter (GD), anteroposterior globe diameter (APGD), globe surface area (GS). The growth model of each biometric against gestational age (GA), aspect ratio of lens and globe (LD/APLD and GD/APGD), and growing relationship between the ratio of lens and globe surface area (LS/GS) were studied by statistical analysis.
    UNASSIGNED: The growth model of most biometry for gestational age is logarithmic, except for the diameter of the ocular globe (GD and APGD) showing a quadratic growth pattern. Our study showed that the lens was consistently larger in the transverse than the anteroposterior diameters during 21-39 weeks(P < 0.001). Besides, the ratio of surface area (LS/GS) was not significantly changing with GA(P = 0.4908), while the increase of LS was significantly accorded with that of GS(P < 0.001).
    UNASSIGNED: The lens shape throughout fetal life may take part in the process, shape changing from vertical ellipsoid, spherical to transversal ellipsoid, based on the logarithmically increased ratio of lens transverse and anteroposterior diameters. In the meanwhile, the aspect ratio of eyeball in late fetal life may imply a gradually spherical shape during gestation. Nomogram data from this study may provide appropriate information about morphological changes in the fetal lens and the synchronous relationship between lens and eyeball.
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  • 文章类型: Review
    目的:老花眼-随着年龄的增长,近焦点的逐渐丧失-主要是晶状体生物力学变化的结果。特别是,在没有小带张力的情况下,晶状体的形状在整个成年期都发生了显着变化。造成这种形状变化的因素是晶状体生物力学特性的变化,连续体积生长透镜,可能还有晶状体囊的重塑.这方面的知识增长迅速,因此,这次小型审查的目的是总结和综合这些成果。方法:我们回顾了该领域的最新文献。结果:与年龄相关的生物力学特性变化的机制仍然未知。我们最近表明,晶状体的生长可能是由带状张力驱动的。驱动晶状体生长的相同机械生物学机制也可能导致囊的重塑,尽管这还有待证明。结论:本小型综述侧重于确定导致这些年龄相关变化的机制,建议未来的工作可能会阐明这些机制,并简要讨论了正在进行的努力,以开发一种非手术方法来治疗老花眼。我们还提出了一个将晶状体生长和生物力学特性联系起来的简单模型。
    Purpose: Presbyopia-the progressive loss of near focus with age-is primarily a result of changes in lens biomechanics. In particular, the shape of the ocular lens in the absence of zonular tension changes significantly throughout adulthood. Contributors to this change in shape are changes in lens biomechanical properties, continuous volumetric growth lens, and possibly remodeling of the lens capsule. Knowledge in this area is growing rapidly, so the purpose of this mini-review was to summarize and synthesize these gains.Methods: We review the recent literature in this field.Results: The mechanisms governing age-related changes in biomechanical properties remains unknown. We have recently shown that lens growth may be driven by zonular tension. The same mechanobiological mechanism driving lens growth may also lead to remodeling of the capsule, though this remains to be demonstrated.Conclusions: This mini-review focuses on identifying mechanisms which cause these age-related changes, suggesting future work which may elucidate these mechanisms, and briefly discusses ongoing efforts to develop a non-surgical approach for therapeutic management of presbyopia. We also propose a simple model linking lens growth and biomechanical properties.
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