Ⅰ型胶原基因与近视关系的研究进展

目前近视的发生率很高,但发病机制不清.实验性近视眼和人类近视眼研究发现,I型胶原基因变化与近视发生、发展关系密切,本文就Ⅰ型胶原基因的表达调控及其与近视的关系作一综述.     

近视眼巩膜胶原的研究现状

病理性近视常引致视功能不可逆性损害。通过对实验性近视眼和人类近视眼研究发现,巩膜胶原变化与该病发生、发展关系密切。本文就胶原结构、力学特性、近视眼及后巩膜加固术后胶原变化等方面进行综述。     

近视与巩膜胶原关系的研究进展

近视是一种发病率极高的屈光不正,而病理性近视可以导致严重致盲性并发症,其发生的原因主要是细胞外基质的重塑,眼轴的延长。然而胶原是细胞外基质的主要成分,在近视的发生、发展中起重要作用。明确近视眼胶原改变的关键因子有望揭示近视的发病机制。本文就目前近视与巩膜胶原关系的研究进展进行综述。     

变性近视与眼压和E值的关系

近视是眼科常见的遗传性眼病,正常群体的发病率可高达30.39%,变性近视(≥6D)占6.89%。近年来近视眼中开角型青光眼的患病率明显升高。二者均具有胶原组织的病理改变,变性近视眼巩膜曲率半径增大、变薄而发生眼球扩大。这种薄而膨胀的巩膜对眼压有一定的影响,因而用Schi(?)tz 眼压计测置眼压时往往造成一种假性低眼压,这对变性近视眼中开角型青光眼的诊断往往造成贻误。笔者为研究变性近视     

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。     

眼压与近视关系的研究进展

近视的发生和发展机制至今尚未明确.眼压与近视发生发展、近视与青光眼的关系一直以来受到关注,并有不少临床和基础研究.文中就近视眼与眼压、近视眼与青光眼相互关系的研究和观点进行综述.     

豚鼠进展性近视眼巩膜中Smad3和Ⅰ型胶原的动态表达变化

背景 巩膜重塑过程中导致眼轴的伸长是轴性近视进展的主要病理机制之一.研究证实转化生长因子β1(TGF-β1)参与巩膜重塑过程,而Smad3是TGF-β1的下游信号转录基因之一,探讨其在近视眼巩膜重塑过程中的作用对于近视发病机制和防治研究具有重要意义. 目的 研究近视眼巩膜重塑过程中Smad3和Ⅰ型胶原的表达情况,探讨TGF-β1-Smad3-Collagen Ⅰ信号途径在近视巩膜胶原重塑中的作用.方法 将出生后7d的豚鼠75只任意分为空白对照组(25只)和形觉剥夺性近视(FDM)组(50只).FDM组豚鼠采用半透明乳胶遮盖左眼的方法制备单眼FDM模型,右侧未遮盖眼作为自身对照.FDM组分别遮盖2、4、6周,另一组动物遮盖4周后去遮盖1周,分别于遮盖前及上述时间点采用检影法测量各组豚鼠双眼屈光度,采用A型超声手动模式测量豚鼠眼轴长度.于上述时间点分别处死5只豚鼠并制备巩膜组织切片,分别采用免疫组织化学法及逆转录PCR法检测各组豚鼠巩膜组织中Smad3和Ⅰ型胶原蛋白及其mRNA的相对表达量.结果 遮盖前空白对照组与FDM组豚鼠屈光度均为远视状态,差异无统计学意义(P＞0.05),空白对照组豚鼠远视屈光度逐渐下降,而FDM组豚鼠在遮盖前,遮盖2、4、6周及遮盖4周后去遮盖1周屈光度从(+2.09±0.31)D逐渐改变为(-1.23±0.69)、(-4.17±0.59)、(-7.07±0.56)和(-4.30±0.58)D,眼轴长度从(5.93±0.39)mm逐渐改变为(6.62±0.36)、(7.30±0.34)、(7.99±0.32)和(7.21±0.36) mm,与空白对照组比较,遮盖后各时间点FDM组豚鼠近视度明显升高,眼轴测量值明显增加,差异均有统计学意义(均P＜0.01).与自身对照组比较,遮盖2周、4周、遮盖4周后去遮盖1周及遮盖6周时FDM组近视度均明显升高,眼轴明显增长,差异均有统计学意义(均P＜0.05).遮盖前空白对照组与FDM组豚鼠后极部巩膜组织中Ⅰ型胶原和Smad3蛋白及其mRNA相对表达量的差异均无统计学意义(均P＞0.05),FDM组豚鼠遮盖2、4、6周及遮盖4周后去遮盖1周巩膜组织中Ⅰ型胶原和Smad3蛋白及其mRNA相对表达量均明显低于空白对照组和自身对照组,差异均有统计学意义(均P＜0.05).豚鼠巩膜组织中Ⅰ型胶原蛋白与Smad3蛋白及其mRNA相对表达量均呈明显正相关(蛋白:r=0.993,P＜0.05;mRNA:r =0.954,P＜0.05). 结论 FDM豚鼠模型眼随着遮盖时间的延长近视度明显增加,眼轴明显增长,豚鼠巩膜组织中Smad3和Ⅰ型胶原的表达相应减弱,且Smad3和Ⅰ型胶原表达量的变化趋势高度一致.Smad3和Ⅰ型胶原可能通过TGF-β1-Smad3-Collagen Ⅰ信号途径参与近视眼巩膜重塑过程的调控.     

病理性近视眼患者血清的羟脯氨酸浓度改变

目的了解病理性近视眼患者是否存在全身性胶原代谢改变.方法病理性近视眼患者25例,正视眼对照23例,取晨间空腹静脉血的血清,以盐酸水解后按氯胺T氧化比色法测羟脯氨酸浓度.结果病理性近视眼组血清羟脯氨酸浓度为(25.084±6.996)μg/ml,对照组为(18.286±3.417)μg/ml,有显著性差异(非参数检验,P＜0.001).病理性近视眼患者血清的羟脯氨酸浓度与近视程度无显著相关性(P＞0.05).结论部分病理性近视眼患者可能存在着全身性的胶原代谢异常.     

高度近视与原发性开角型青光眼

临床上发现高度近视与原发性开角型青光眼密切相关 ,其可能的机制有 :( 1 )升压基因学说 ;( 2 )胶原基因学说。高度近视眼与原发性开角型青光眼对糖皮质激素反应增高表明 ,二者的基因在糖皮质激素诱导下最易表达特异性蛋白 ,这可能与高度近视、原发性开角型青光眼的TIGR基因突变有关。本文从流行病学、临床特征及诊断、遗传学说及机制等方面对高度近视与原发性开角型青光眼的关系及研究进展进行综述。     

病理性近视的基因研究

病理性近视是引起亚洲人群视力损害的常见原因之一,它的发生与遗传因素高度相关.目前,已发现多个病理性近视的候选基因位点,包括胶原类基因、基膜类基因、生长因子类基因、转录因子类基因等,它们作用于巩膜、角膜、视网膜等不同部位从而影响眼生长发育并引起病理性近视.     

MMPs激动剂和抑制剂对人巩膜成纤维细胞MMP-1／2以及I型胶原表达的作用研究

目的研究基质金属蛋白酶（MMPs）家族MMP-1、MMP-2激动剂和抑制剂对人巩膜I型胶原表达的作用,探讨MMP-1和MMP-2在人巩膜胶原代谢中的作用。方法应用人巩膜成纤维细胞系作为研究模型,用荧光定量检测MMPs激动剂醋酸氨基苯汞（APMA）及抑制剂对人巩膜成纤维细胞MMP-1和MMP-2活性的影响;实时荧光定量反转录聚合酶链反应以及免疫印迹蛋白定量法检测比较激动剂组与抑制剂组对MMP-1／2以及I型胶原mRNA和蛋白表达的变化;最后用siRNA干扰敲除MMP-1、MMP．2或MMP-1／2后,检测巩膜成纤维细胞I型胶原蛋白水平的变化。结果MMPs激动剂引起MMP．1／2活性显著增加,I型胶原mRNA和蛋白表达下降,MMPs抑制剂引起MMP．1／2活性显著下降,相应的I型胶原mRNA和蛋白表达增加（均P〈0．01）。激动剂可引起MMP．1mRNA表达增加（P〈0．01）,对MMP-2mRNA表达无明显影响（P〉0．05）,而抑制剂能引起MMP．2mRNA表达下降（P〈0．01）,但对MMP．1mRNA表达无显著影响（P〉0．05）。应用siRNA干扰方法敲除MMP-1、MMP-2或两者同时被敲除后,MMP-1蛋白表达均显著降低（均P〈0．01）,MMP-2除在MMP-1siRNA干扰敲除组无明显变化外（P〉0．05）,其余各组均显著下降（均P〈0．01）;I型胶原的表达在各敲除组中显著增加,当MMP-1和MMP．2均干扰敲除时,I型胶原的表达增加最为显著（均P〈0．01）。结论在人巩膜成纤维细胞系中,MMP-1／2激动剂和抑制剂均能引起MMP-1／2活性改变及相应的MMP-1／2蛋白表达变化,并最终导致I型胶原表达的变化;MMP．1和MMP-2是调控人巩膜I型胶原重塑的关键因子。     

TIMP-2基因转染后豚鼠形觉剥夺眼后极部巩膜Ⅰ型胶原和纤维连接蛋白的表达

背景细胞外基质（ECM）蛋白和酶参与眼球后极部巩膜主动的重塑过程,主要通过影响I型胶原蛋白（Col-Ⅰ）纤维连接蛋白（FN）发挥作用。目的通过对形觉剥夺性近视（FDM）豚鼠经脉络膜上腔注入转染有TIMP-2基因的脂质体,观察基质金属蛋白酶抑制剂-2（TIMP-2）对细胞外基质中Ⅰ型胶原蛋白（Col-Ⅰ）和FNmRNA表达的影响。方法半透明眼罩遮盖36只豚鼠的右眼14d建立FDM动物模型,用随机数字表法分组后分别于右眼脉络膜上腔注入5p,1TIMP-2脂质体质粒、空质粒和生理盐水,每组12只眼,左眼为自身对照。另12只豚鼠持续遮盖右眼为模型对照组。分别于脉络膜上腔注药后的2、7、14d过量麻醉处死豚鼠,获取眼球后极部巩膜组织,用RT-PCR法分别检测各组豚鼠眼巩膜组织中Col-Ⅰ和FNmRNA的表达。结果TIMP-2组豚鼠后极部巩膜Col-Ⅰ mRNA表达降低,FNmRNA表达升高,与自身对照相比差异均有统计学意义（P〈0．05）。注入TIMP-2后,Col-I mRNA表达水平从第2天开始升高,第7天达到高峰,第14天时有所回落;FNmRNA表达水平则呈相反变化。二者在第7天、第14天的表达与其他3组间比较差异均有统计学意义（P〈0．05）。C01．ImRNA和FNmRNA表达水平在注射后第7天与第2天或第14天比较差异均有统计学意义（P〈0．01）。结论TIMP-2注入FDM豚鼠脉络膜上腔可上调Col-I mRNA表达,下调FNmRNA表达,早期可有减缓豚鼠FDM巩膜重塑的作用。     

Expressions of type I collagen, α2 integrin and β1 integrin in sclera of guinea pig with defocus myopia and inhibitory effects of bFGF on the formation of myopia

AIM: Toinvestigate the expressions of type I collagen, α2 integrin and β1 integrin in the posterior sclera of guinea pigs with defocus myopia and whether basic fibroblast growth factor (bFGF) injection inhibits the formation and development of myopia by upregulating the expression of type I collagen, α2 integrin and β1 integrin.METHODS: After 14 days of treatment, the refractive state and axial length were measured and the levels of type I collagen, α2 integrin and β1 integrin were assayed in the posterior sclerae of groups of guinea pigs that wore a monocular -7D polymethylmethacrylate (PMMA) lens or had -7D lens wear followed by the peribulbar injection of Phosphate Buffer Solution (PBS) or bFGF. The untreated fellow eye served as a control. Guinea pigs with no treatment served as normal group.RESULTS: The results showed that 14 days of monocular defocus increased axial eye length and refraction, while bFGF delivery inhibited them markedly. Further, it was also found that the monocular -7D lens could decrease the levels of type I collagen, α2 integrin and β1 integrin expressions, while, unlike PBS, bFGF increased them significantly in comparison to contralateral control eyes and normal eyes.CONCLUSION: bFGF can prevent the formation and development of defocus myopia by upregulating the expressions of type I collagen, α2 integrin and β1 integrin. Taken together, our results demonstrate that bFGF promotes sclera remodeling to prevent myopia in guinea pigs.     

Association of COL1A1 polymorphism with high myopia: a Meta-analysis

AIM: To investigate the association between collagen type I alpha 1 (COL1A1) gene and high myopia. METHODS: In this Meta-analysis, we examined 5 published case-control studies that involved 1942 high myopia cases and 2929 healthy controls to assess the association between the COL1A1 rs2075555 polymorphism and high myopia risk. We calculated the pooled odds ratios (ORs) of COL1A1 rs2075555 polymorphism in high myopia cases vs healthy controls to evaluate the strength of the association. RESULTS: Overall, there was no significant difference both in the genotype and allele distributions of COL1A1 rs2075555 polymorphism between high myopia cases and healthy controls: CC vs AA OR=1.10, 95% confidence interval (CI)=0.76-1.58; AC vs AA OR=0.98, 95%CI 0.80-1.20; CC/AC vs AA/OR=1.01, 95%CI 0.84-1.22; CC vs AC/AA OR=1.06, 95%CI=0.93-1.20; C vs A OR=1.06, 95%CI 0.91-1.23). In addition, in the stratified analyses by ethnicity, no significant associations were found in any genetic model both in European and Asia cohorts. CONCLUSION: Our results indicate that the COL1A1 rs2075555 polymorphism may not affect susceptibility to high myopia.     

Evaluation of selected parameters of collagen metabolism in patients with myopia

INTRODUCTION: Myopia is a common condition of vision deprivation characterized by the excessive lengthening of the eye axis. There are hypotheses that the elongation of the eye is connected with the connective tissue disorder in which the scleral collagens are inappropriately remodelled. The most common type of collagen and the first to be discovered is type I and it is the dominating one in cornea and sclera. Type III is always found in coexistence with type I. AIMS: The aim of the study was to evaluate the serum concentration of carboxyterminal propeptyde of procollagen type I (P I CP), aminoterminal propeptyde of procollagen type III (P III NP) (markers of collagen synthesis) and carboxyterminal telopeptyde of collagen type I (I CTP) (marker of collagen disintegration) as markers of the connective tissue metabolism in patients with myopia. MATERIAL AND METHODS: Serum concentration of P I CP, P III NP and I CTP were studied in 25 (15 female and 10 male) patients with myopia and in 15 emmetropic subjects using the RIA method (Orion Diagnostica). RESULTS: The serum concentration of P I CP and P III NP increased significantly in patients with myopia when compared with the control group. There was no significant difference in the concentration of both of them among patients with various degrees of myopia, although the concentration of P I CP and P III NP increased with the increase of myopia. The was no statistical difference in the concentration of I CTP in low and medium myopia but we found increased concentration of I CTP in high myopia comparing with control group. CONCLUSION: The mechanical properties as well as the increased remodelling of the collagen could be some of the factors involved in myopia pathogenesis. Changes in the collagen metabolism concern not only the eye tissue, but probably also disorders of the systemic connective tissue turnover.     

I型和II 型胶原在正常角膜和圆锥角膜中的表达

目的　观察正常人及圆锥角膜中 I、II型的表达 ,探讨胶原 I、II型在圆锥角膜病变中的变化。方法　采用免疫组织化学 - SA BC法检测角膜组织中胶原 I、II型胶原的表达。结果　胶原 I型在正常角膜和圆锥角膜的上皮层、实质层及内皮层均有阳性表达 ,但圆锥角膜比正常角膜的表达弱 ;而胶原 II型在正常角膜和圆锥角膜组织的基质层和 Bow m an层均可检测到 ,但圆锥角膜中 II型胶原表达减低 ,在圆锥角膜基质斑块状瘢痕区 II型胶原呈强阳性表达。结论　 I、II型胶原的减少会导致角膜的稳定性降低 ,使角膜的机械抵抗力减弱 ,并使角膜前凸变薄。     

巩膜胶原交联疗法治疗进行性近视的研究进展

胶原交联是指胶原分子内部和胶原分子间通过共价键结合实现提高胶原纤维的张力和稳定性的目的 .胶原交联被广泛应用于其他行业,近期研究表明胶原交联可改变巩膜的生物力学性质,使其抗牵拉能力增强,从而阻止进行性近视的发展恶化,有望成为治疗进行性近视的新疗法,本文对进行性近视巩膜胶原的特点、传统治疗方法及巩膜胶原交联疗法的研究现状做一阐述.     

极低频电磁辐射下HFSF中MMP-2的表达及作用

目的研究极低频电磁场（ELF-EMF）作用下人胚胎眼巩膜成纤维细胞（HFSF）中基质金属蛋白酶-2（MMP-2）活性与蛋白表达的变化以及ELF-EMF对I型胶原（Collagen I）合成的影响。方法实验研究。根据是否暴露于50 Hz、0.2 mT电磁场或加入MMP-2特异性抑制剂（sc-204092）,将实验细胞分为对照组、辐照组和抑制剂组。明胶酶谱法检测各组HFSF中MMP-2酶活性的变化;Western Blot法检测各组HFSF中MMP-2、Collagen I蛋白水平的变化。采用单因素方差分析进行数据分析。结果3组HFSF细胞中MMP-2酶活性、MMP-2、Collagen I蛋白表达比较差异均具有统计学意义（F=14.96、139.88、63.46,P均<0.01）;辐照组较对照组MMP-2酶活性和蛋白表达升高（P<0.05）,Collagen I蛋白表达下降（P<0.01）;抑制剂组较辐照组MMP-2酶活性和蛋白表达下降（P<0.01）,Collagen I蛋白表达升高（P<0.05）。结论ELF-EMF可能通过影响体外培养的HFSF中MMP-2的酶活性和蛋白表达来调节Collagen I的合成。     

Heterogeneity of the bovine corneal collagen

Type III collagen [α₁ (III)] was isolated from the pepsin-solubilized bovine corneal collagen either by differential salt precipitation, or by molecular sieve chromatography. It has been estimated that type III collagen represents about 20% of the total collagen, the predominant part of which is type I collagen. The identity of type III collagen was verified by molecular sieve chromatography and polyacrylamide gel electrophoresis of reduced and alkylated γ-chains, and by CNBr cleavage and amino acid analysis of isolated α₁ (III) chains.