负透镜诱导豚鼠离焦性近视眼巩膜胶原密度及形态学改变

目的探讨新生豚鼠负透镜诱导离焦性近视发生时巩膜胶原密度和形态的变化。方法30只新生有色豚鼠随机分成透镜诱导组（单眼-10.00D透镜诱导）和正常对照组（无处理组）,第28天测量屈光度,眼球冰冻切片行VanGieson胶原染色,以锯齿缘为界分别分析前后部巩膜胶原密度;并进行电镜扫描观察巩膜胶原纤维直径。结果新生豚鼠28d透镜诱导组诱导眼的平均球镜等值屈光度低于对侧眼（P〈0.01）;诱导眼后部巩膜胶原染色光密度值低于对侧眼（P〈0.01）;诱导眼和对侧眼屈光度差值与后部巩膜胶原染色光密度差值呈正相关（r=0.84,P〈0.01）;诱导眼后部巩膜胶原纤维直径小于对侧眼（P〈0.01）;诱导眼前部巩膜胶原密度和胶原直径与对侧眼相比,差异无统计学意义（P〉0.05）;新生豚鼠28d诱导组对侧眼各项指标与对照组相比,差异无统计学意义（P〉0.05）。结论新生豚鼠负透镜诱导离焦性近视时后部巩膜胶原密度减少,伴胶原直径的减小,影响胶原代谢的机制尚需进一步研究。     

Effects of 7‐methylxanthine on the sclera in form deprivation myopia in guinea pigs

Purpose: The aim of this study was to determine the effect of the adenosine receptor antagonist 7‐methylxanthine (7‐MX) on form deprivation myopia in 3‐week‐old guinea pigs. Methods: Two groups of 3‐week‐old guinea pigs were subjected to monocular deprivation (MD) using a diffuser and fed either 7‐MX (300 mg/kg body weight; n = 7) or vehicle control (saline at an equal volume to 7‐MX; n = 7). A control group (n = 6) was not subjected to form deprivation. Ocular refraction, axial length and body weight were measured at the start and after 21 days. The thickness of the posterior sclera was measured by light microscopy and the collagen fibril diameter in the inner, middle and outer layers of the sclera was measured by electron microscopy. Results: In the vehicle control group, 21 days of MD produced significant amounts of myopia, axial elongation, thinning of the posterior sclera and thinning of the median collagen fibril diameter in the posterior sclera relative to the contralateral eyes. In the guinea pigs fed with 7‐MX, however, form deprivation produced significantly less myopia and axial elongation compared with vehicle control animals. The 7‐MX‐treated animals exhibited a thickening of the posterior sclera in both the MD eye and the contralateral eye. In the 7‐MX‐treated animals, the median collagen fibril diameter in the posterior sclera was not reduced by form deprivation. Conclusions: Treatment with 7‐MX appears to not only decrease the amount of myopia by around 50% and eliminate the eye elongation induced by form deprivation in guinea pigs, but also to prevent form deprivation myopia‐related scleral changes, such as thinning of the sclera and thinning of the collagen fibril diameter in the posterior sclera.     

Protective effects of riboflavin-UVA-mediated posterior sclera collagen cross-linking in a guinea pig model of form-deprived myopia

AIM:To evaluate the effect of posterior sclera collagen cross-linking induced by riboflavin-ultraviolet A(UVA)on form-deprived myopia in guinea pigs.METHODES:Twenty-five pigmented guinea pigs of 3-week-old were randomly assigned into 4 groups that included normal control(NOR,n=7),form-deprived(FDM,n=7),normal with riboflavin-UVA cross-linking(NOR+CL,n=5)and form-deprived with cross-linking(FDM+CL,n=6).The NOR+CL group and the FDM+CL group received the riboflavin-UVA induced cross-linking at day 0.FDM was induced by monocularly deprived with facemask in the right eyes.The refraction,axial length and corneal curvature were measured by retinoscopy,A-scan and keratometer respectively in scheduled time points(day 0 and 1,2,3,4 wk after form-deprivation).At the end of 4 weeks’experiment,stress-strain tests of sclera were measured and morphological changes of sclera and retina were examined.RESULTS:After 4 wk,the interocular difference of refractive error were-0.11±0.67,-2.93±0.56,1.10±0.58,and-1.63±0.41 D in the NOR,FDM,NOR+CL,and FDM+CL groups respectively.Mixed-effect linear model revealed significant effect of FDM(P<0.01)and CL(P<0.001).Also,after 4 wk,the interocular difference of axial length were 0.01±0.04,0.29±0.07,-0.13±0.06,and 0.11±0.05 mm in the NOR,FDM,NOR+CL,and FDM+CL group.Mixedeffect linear model revealed significant effect of FDM(P<0.001)and CL(P<0.01).As for corneal curvature,significant interocular difference have not found between any of the two groups.At the end of this experiment,the ultimate stress and elastic modulus were found significantly increased in both CL groups.But no difference was found in the groups without cross-linked.There was no abnormality observed in the retina and RPE cells of the treated eyes.CONCLUSION:The posterior sclera collagen crosslinking induced by riboflavin-UVA can slow down the progress of myopia and increase the sclera biomechanical strength in the guinea pig model of form-deprived myopia.     

鸡形觉剥夺性近视眼后极部巩膜IGF-1R/IGF-2RmRNA的表达

目的：观察鸡形觉剥夺性近视眼后极部巩膜IGF-1R/IGF-2RmRNA表达水平的变化,探讨IGF-1R/IGF-2R在实验性近视眼发生机制中的信号转导作用.方法：孵化1d的白色来亨鸡36只,右眼为遮盖眼,左眼为自身对照眼;测量实验前、单眼遮盖1,2,3wk时遮盖眼和对照眼的屈光度和眼轴长度,并检测不同遮盖时间鸡眼后极部巩膜IGF-1R/IGF-2RmRNA的表达水平.结果：鸡眼后极部巩膜可检测到IGF-1R/IGF-2RmRNA的表达,随着眼球的生长发育其表达水平明显升高;随着遮盖时间的延长,IGF-1R/IGF-2RmRNA在遮盖眼后极部巩膜的表达水平显著升高;遮盖眼后极部巩膜IGF-1RmRNA的表达水平自遮盖1wk起明显高于对照眼;IGF-2RmRNA表达水平则在对照眼与遮盖眼无显著差异.结论：形觉剥夺可能通过上调鸡眼后极部巩膜IGF-1RmRNA表达水平,IGF-1R通过结合IGF并启动下游信息转导途径,从而调控巩膜细胞的增殖和分化,导致近视的发生.     

豚鼠实验怀近视眼巩膜的羟脯氨酸含量改变

目的：探讨胶原水平的变化在哺乳类动物近视眼发生机制中的作用。方法：出生3周的乳花色雄性豚鼠24只,单眼眼睑缝合75天后,检测影响眼轴。后极和前部巩膜分别称重后,以蛋白酶K消化和盐酸水解,用氯胺T氧化比色法测定每毫克巩膜中的羟脯酸含量。结果：豚鼠75天的形觉剥夺诱导了约－9D的相对近视和0．39mm的眼轴延长。剥夺眼部巩膜和后极巩膜的羟脯氨酸含量差异有显著性意义（P＜0．001）;对照前后巩膜的羟脯氨酸含量差异无统计学意义（P＞0．05）。双眼前部巩膜的羟脯氨酸含量差异无统计学意义（P＞0．05）;双眼后部巩膜的羟脯氨酸含量差异有显著性意义（P＜0．001）。结论：豚鼠眼形觉剥夺性近视时,主要是后极部羟脯胺酸含量减少,即后极部的巩膜胶原优先影响。由于后极部巩膜胶原减少,减弱了巩膜的抵抗力,使眼轴易于延展而发生近视。     

豚鼠实验性近视眼巩膜的羟脯氨酸含量改变

目的通过豚鼠形觉剥夺性近视眼巩膜羟脯氨酸含量的检测,分析形觉剥夺对豚鼠巩膜不同区域胶原的影响,探讨胶原水平的变化在哺乳类动物近视眼发生机制中的作用.方法出生3周的断乳花色雄性豚鼠24只,单眼眼睑缝合75d后,检影,测眼轴.后极和前部巩膜分别称重后,以蛋白酶K消化和盐酸水解,氯胺T氧化比色法测每毫克巩膜中的羟脯氨酸含量.结果豚鼠75d的形觉剥夺诱导了约-9D的相对近视和0.39mm的眼轴延长.剥夺眼前部巩膜和后极巩膜的羟脯氨酸含量有显著性统计学差异(P＜0.001);对照眼前后巩膜的羟脯氨酸含量无统计学差异(P＞0.05);双眼前部巩膜的羟脯氨酸含量差异无统计学意义(P＞0.05);双眼后部巩膜的羟脯氨酸含量差异有显著性(P＜0.001).结论豚鼠形觉剥夺性近视眼时,主要是后极部羟脯氨酸含量减少,即后极部的巩膜胶原优先受影响.由于后极部巩膜胶原减少,减弱了巩膜的抵抗力,使眼轴易于延展而发生近视.     

单眼形觉剥夺对豚鼠后极部巩膜整合素β1表达的影响

目的探讨豚鼠形觉剥夺性近视模型中巩膜整合素β1的表达及其与形觉剥夺的关系。方法40只出生后1周花色豚鼠,右眼遮盖作为形觉剥夺组,左眼不作处理作为对照组。遮盖2、4、8周和遮盖8周去遮盖1周后测量屈光度,眼科A超测定眼轴长度;对两组4个时间点眼球后壁行SP法免疫组织化学染色和RT-PCR检测巩膜整合素β1蛋白和mRNA水平的动态变化。结果与对照组相比,形觉剥夺组4个时间点眼球后壁巩膜整合素β1表达明显减少,差异有统计学意义（P〈0.05）,去遮盖1周后,表达上调,但仍低于对照组（P〈0.05）;而对照组间相比较,差异无统计学意义（P〉0.05）;形觉剥夺组和对照组屈光度、眼轴长度比较,差异有显著的统计学意义（P〈0.05）。结论豚鼠形觉剥夺时,后极部巩膜整合素β1表达减少,去遮盖后表达上调,提示整合素β1可能参与了形觉剥夺性近视的发生,其影响巩膜重塑的机制有待进一步研究。     

鸡形觉剥夺性近视眼后极部巩膜胰岛素样生长因子-1/胰岛素样生长因子-2 mRNA表达的动态变化

目的观察鸡形觉剥夺性近视眼后极部巩膜胰岛素样生长因子(insulinlikegrowthfactor,IGF)IGF1/IGFmRNA表达水平的变化,探讨IGF1/IGF2在实验性近视眼发病中的作用。方法取孵化1d的白色来亨鸡36只,右眼为遮盖眼,左眼为自身对照眼。测量实验前以及单眼遮盖后第7天、第14天、第21天时实验眼和对照眼的屈光度和眼轴长度,并检测不同遮盖时间时鸡眼后极部巩膜IGF1/IGF2mRNA的表达水平。结果随着遮盖时间的延长,IGFmRNA在试验眼和对照眼后极部巩膜的表达水平均升高,但两者之间差异无显著性(P>0.05);实验眼后极部巩膜的IGF2mRNA表达水平在遮盖7d后即明显高于对照眼(P<0.001),随着遮盖时间的延长,实验眼后极部巩膜IGF2mRNA表达水平明显升高,而对照眼则逐渐下降,两者的差值明显增大。结论形觉剥夺可能通过上调鸡眼后极部巩膜IGF2mRNA表达水平,影响巩膜的发育和重塑,从而导致近视的形成。     

视黄酸在早期形觉剥夺性近视豚鼠后巩膜中的变化

目的检测豚鼠早期形觉剥夺性近视（FDM）眼巩膜中视黄酸（RA）的水平,探讨RA在FDM眼后极部巩膜中的作用。方法3周龄三色豚鼠30只随机分组,正常对照组6只,形觉剥夺15d组和形觉剥夺24d组各12只,左眼用气球头套分别遮盖15d和24d,右眼为自身对照。实验前后均测量屈光度,实验结束后摘除眼球,测量眼轴长,应用高效液相色谱法（HPLC）测定后极部巩膜RA含量。结果形觉剥夺15d组、形觉剥夺24d组动物实验眼诱导出明显的相对近视,且与正常组比较差异有统计学意义（F=23.053,P〈0.05）。形觉剥夺15d组、形觉剥夺24d组实验眼眼轴均长于自身对照眼（P〈0.05）。形觉剥夺15d组、形觉剥夺24d组实验眼巩膜中RA水平较自身对照眼均明显升高（P〈0.01）,但形觉剥夺15d组、形觉剥夺24d组间比较差异无统计学意义（P=0.857）。结论形觉剥夺可诱导近视,且近视程度在早期随时间递增,形觉剥夺眼眼轴增长。豚鼠早期形觉剥夺眼后极部巩膜RA含量增多,但在15～24d时段内差异无统计学意义。     

豚鼠形觉剥夺性近视形成的影响因素

近视的发病机制为异常的视觉刺激作用于视网膜引起视网膜信号因子的改变,随后通过视网膜色素上皮层-脉络膜途径传导至巩膜,诱导细胞外基质重构,导致巩膜重塑.豚鼠形觉剥夺性近视(form-deprived myopia,FDM)是研究近视的常用模型之一,对豚鼠FDM的研究主要集中在使用不同的药物如一氧化氮合酶、褪黑素、M受体阻...     

实验性近视眼的主动补偿机制

近视眼动物模型的建立为人类近视眼发病机制的研究提供了一条新途径。目前的研究表明，实验性近视眼的发生是视网膜成像质量下降刺激眼球主动生长的结果。眼球的主动生长过程主要表现为巩膜的生长重塑和脉络膜厚度变化，因此对这两个方面的变化机制作一综述。     

视网膜对形觉剥夺性近视鸡巩膜MMP-2的调控

目的建立鸡形觉剥夺性动物模型,通过观察用庆大霉素破坏小鸡视网膜后,后极部巩膜基质金属蛋白酶Ⅱ(matrix metalloproteinase-2,MMP-2)的变化,探讨视网膜在形觉剥夺性近视(formdeprivation myopia,FDM)发生、发展中的影响作用。方法48只白色来亨鸡(鸡龄2d,SPF级)分为A、B、C、D4组,每组12只,其中A组、B组在第2d即行双眼半透明眼罩遮盖同时行右眼玻璃体内1次注射庆大霉素400μg;C组仅右眼玻璃体内1次注射庆大霉素400μg不予遮盖,左眼不作处理为自身对照;D组不作任何处理,为正常对照组。在第3周末,对全部小鸡行检影验光测屈光度后,将A、C2组鸡处死,迅速摘除双眼球,测量其前后径。并随机取出2只送病理组织切片;B组摘除双眼眼罩后继续饲养3周,在第6周末对B、D2组行检影验光后将其处死,摘除双眼球测量眼球前后径。用7mm直径环钻钻取后极部巩膜组织,研磨离心后取上清液作为标本,对所有标本采用ELISA(即酶联免疫吸附)试剂盒测定MMP-2活性浓度。所有数据经过EXCEL和SPSS统计软件进行处理。结果第3周末,A、B两组双眼屈光度之间均具有显著性差异(P<0·001),C组和D组双眼屈光度间无显著性差异(P=0·088,0·920),且A、B2组与C组双眼屈光度比较均分别具有显著性差异(P<0·001);A组双眼眼轴测量值具有显著性差异(P<0.01),C组双眼眼轴未见显著性差异(P>0.05),A组与C组比较时,右眼眼轴无显著性差异(P>0.05),而左眼间差异具有显著性(P<0.001);第6周末,B组去遮盖后双眼屈光度及眼轴测量值之间均无显著性差异(P>0.05),且与D组比较差异亦无显著性意义(P>0.05),但B组去遮盖前后双眼屈光度之间具有明显显著性差异(P<0.001)。ELISA结果显示,除了A组双眼后级部巩膜MMP-2含量自身对照及与其他各组比较均有显著性差异外(P<0.001),另外3组之间差异均无显著性意义(P>0.05)。结论视网膜色素上皮层在形觉剥夺性近视的发生发展过程中起着非常重要的作用,破坏视网膜色素上皮层能一定程度的减轻近视的发展程度。     

玻璃体切割联合后巩膜加固术治疗高度近视眼黄斑裂孔性视网膜脱离

目的：探讨玻璃体切割联合后巩膜加固治疗高度近视眼黄斑裂孔伴视网膜脱离的方法与疗效。
　　方法：于2012-01/2013-12间收集高度近视性黄斑裂孔伴视网膜脱离患者45例45眼,分为玻璃体切割内界膜撕除联合后巩膜加固组( A组)28眼和玻璃体切割内界膜撕除组( B组)17眼。术前分别行视力、眼压、间接检眼镜、OCT检查,术后随访6~12mo,行视力、OCT检查,分别对视力、视网膜复位情况、黄斑裂孔闭合情况进行统计比较。
　　结果：(1)视力检查：术后视力：A 组1.19±0.39, B 组1.51±0.34,二者比较有显著性差异(P<0.05);(2)术后视网膜复位率：A组100%,B组88.24%,两者比较无统计学差异;(3)术后黄斑裂孔闭合率：A 组82%,B 组53%,两者比较有统计学差异(P<0.05)。
　　结论：玻璃体切割术联合后巩膜加固术治疗高度近视眼黄斑裂孔伴视网膜脱离的手术方法安全可行,可更好的改善视力,提高黄斑裂孔的闭合率。     

生长因子在近视发展中的作用研究进展

近视是眼科发病率最高的疾病,但目前对近视发病机制的了解仍然有限。近年来研究发现生长因子在控制眼球大小导致近视发生中起着重要作用,多种生长因子参与眼球的主动生长和重新塑形,与近视的发生发展密切相关。我们就近年来与近视相关的生长因子的研究进行综述,为进一步探讨近视的发病机制提供理论参考。     

近视眼巩膜的变化及其发生机制

本文综述鸡、树鼠、猴子和人类近视眼巩膜的组织病理学、生化和代谢等方面的变化。目前认为巩膜的近视性改变,可能主要是与生长因子和基质金属蛋白酶活性调控失平衡、局部血流动力学紊乱、乱病胶原基因等所致的胶原代谢异常有关。     

豚鼠形觉剥夺性近视眼后极部巩膜蛋白多糖水平的变化

目的观察豚鼠形觉剥夺性近视眼模型后极部巩膜蛋白多糖水平的变化,探讨其在哺乳类动物近视眼发生机制中的作用。方法出生2~3周的断乳花色豚鼠20只,随机均分成2组。遮盖组右眼予不透明眼罩遮盖2周,去遮盖组右眼遮盖2周后去遮盖1周。左眼开放为自身对照眼。于实验开始及结束时检影、测眼轴,达规定时限后处死动物,取后极部巩膜,行免疫组织化学及RT-PCR反应,检测decorin核心蛋白及其mRNA的表达。试验数据采用配对t检验和方差分析进行统计学处理。结果豚鼠遮盖组诱导的相对近视约-8.15 D,眼轴相对增长约0.63 mm;去遮盖组相对近视约-4.30 D,眼轴相对增长约0.57 mm。去遮盖组屈光程度下降值明显小于遮盖组(F=5.974,P<0.05)。免疫组织化学法及RT-PCR法示遮盖组和去遮盖组的实验眼和自身对照眼后极部巩膜均有decorin核心蛋白及其mRNA表达;其mRNA相对含量在组内比较差异均有显著性(P<0.05)。结论豚鼠形觉剥夺性近视眼后极部巩膜decorin mRNA表达显著降低,去除遮盖后其表达上调,提示decorin可能参与了形觉剥夺性近视眼的发生。     

Comparison of form-deprived myopia and lens-induced myopia in guinea pigs

AIM: To study the efficacy difference between form-deprived myopia (FDM) and lens-induced myopia (LIM), the degree of myopia, axial length and pathological changes of the posterior sclera from guinea pigs were evaluated.METHODS: Four-week pigmented guinea pigs were randomly assigned into 3 groups, including normal control (n=6), FDM group with monocular cover (n=11) and LIM group with monocular -7D lens treatment (n=11). FDM group was form-deprived while LIM group was lens-induced for 14 d. Refractive error and axial length were measured prior to and post treatment, respectively. Morphological changes of sclera were examined using both light and electronic microscopes.RESULTS: After 14d treatment, refractive errors for FDM group and LIM group were -3.05±0.71D and -2.12±1.29D, respectively, which were significantly more myopic than that of normal controls and fellow control eyes (P<0.01). As for axial length, it was 7.93±0.03 mm for FDM group and 7.89±0.06 mm for LIM group, which were significantly longer than both normal and fellow controls (P<0.01). With respect to both refractory error and axial length, the differences between FDM group and LIM group were not significant (P>0.05). Under light microscope, both FDM group and LIM group showed thinned sclera, disarrangement of fibrosis and enlarged disassociation between fibers. Consistently, ultrastructural examination showed degenerated fibroblasts and thinned fibers in posterior sclera.CONCLUSION:Following two weeks of myopia induction in guinea pigs, with regard to the degree of myopia, axial length and pathological alterations, there was no significant difference between FDM and LIM models. Therefore, FDM and LIM are equally effective and useful as a model of experimental myopia and guinea pigs are ideal animals for induction of experimental myopia because their high sensitivity to both form-deprivation and lens-induction.     

小鸡形觉剥夺性近视眼后极部巩膜MMP-2与TIMP-2 mRNA表达的动态变化

目的　探讨小鸡形觉剥夺性近视眼 (form deprivationmyopia,FDM )后极部巩膜基质金属蛋白酶 2 (matrixmetalloproteinase 2 ,MMP 2 )及其特异性组织抑制剂 (tissuein hibitorofmatrixmetalloproteinase 2 ,TIMP 2 )mRNA表达的时间动态性变化。方法　 5 0只 1d龄来亨雏鸡以半透明眼罩分别遮盖右眼 4、7、14、2 1、30d制备FDM动物模型 ,每组10只 ,未遮盖眼为自身对照眼 ,并随机选取同数目同龄小鸡作为正常对照眼。实验前及预定实验时间进行视网膜检影验光和眼轴长度测量。摘除眼球 ,提取后极部巩膜总RNA ,采用一步法逆转录 聚合酶链反应检测每组小鸡后极部巩膜MMP 2、TIMP 2mRNA表达水平。结果　与正常组、自身对照组相比 ,FDM后极部巩膜MMP 2mRNA显著增高 ,TIMP 2mRNA表达明显降低 ,组间差异非常显著 (P <0 .0 1)。随遮盖时间延长 ,MMP 2mRNA表达逐渐上调 ,7～ 2 1d达最高峰 ,以后轻度下降 ,但仍维持于一较高水平 ,不同遮盖时间组间差异显著 (P <0 .0 1) ,而TIMP 2mRNA表达与之相反。自身对照组MMP 2mRNA表达较同龄正常对照组有轻度上调趋势 ,TIMP 2有下调趋势 ,但组间均无统计学差异 (P >0 0 5 )。结论　MMP 2 /TIMP 2之间动态平衡失调极可能是启动小鸡FDM巩膜细胞外基质早期主动重塑的关键