醛糖还原酶抑制剂AL-1576对大鼠半乳糖性白内障的防治研究

背景 糖性白内障是糖尿病的主要眼部并发症之一,研究表明醛糖还原酶(AR)活性的升高与糖尿病的慢性并发症密切相关,是抗糖性白内障药物研究的重要靶点,其研究对糖性白内障的防治具有重要意义. 目的 探讨AR抑制剂AL-1576对半乳糖性白内障的防治效果和作用机制. 方法 4～5周龄SD大鼠42只,通过喂养质量分数50％半乳糖饲料制作半乳糖性白内障模型.大鼠按照随机数字表法平均分为7个组,AL-1576预防组,早、中、晚期治疗组在喂食50％半乳糖饲料的当天及5、10、15d后开始添加质量分数0.0125％ AL-1576,另设空白对照组、模型对照组和AL-1576干预10d后撤除的早期撤药组.在裂隙灯显微镜下动态观察各组大鼠晶状体的混浊程度并进行分级,造模35 d时摘出晶状体,分别测量其干质量、湿质量,计算并比较各组晶状体含水量的变化;检测造模35 d时各组大鼠晶状体内AR活性、超氧化物歧化酶(SOD)活性以及谷胱甘肽( GSH)的含量.结果 模型对照组大鼠12只眼晶状体均为Ⅳ级混浊,AL-1576预防组12只眼晶状体均透明,早期撤药组为Ⅱ～Ⅲ级混浊,早期治疗组为Ⅱ级混浊,而中期治疗组、晚期治疗组均为Ⅲ～Ⅳ级混浊,7个组晶状体混浊的程度差异均有统计学意义(H=17.760,P=0.009).各AL-1576治疗组大鼠晶状体含水量、AR活性均比模型对照组明显降低,差异均有统计学意义(P＜0.05),但给药的时间越晚,晶状体含水量、AR活性降低的程度越小;各AL-1576治疗组大鼠晶状体SOD活性和GSH的含量明显高于模型对照组,差异均有统计学意义( P＜0.05),AL-1576预防组的升高幅度最大. 结论 在半乳糖性白内障形成的不同阶段给予AR抑制剂AL-1576可明显抑制AR的活性.AL-1576通过阻断和减轻晶状体水肿,提高晶状体的抗氧化能力,预防和延缓晶状体混浊的发生.     

Effect of 3,5-di-t-butyl-4-hydroxytoluene (BHT) on glutathione-linked detoxification mechanisms of rat ocular lens

When rats were orally administered a daily dose of 300 mg kg-1 body weight of 3,5-di-t-butyl-4-hydroxytoluene (BHT) for 4 days, about 90% increase over basal level in total glutathione (GSH) S-transferase activity towards 1-chloro-2,4-dinitrobenzene (CDNB) was observed in ocular lens. GSH S-transferase activity in the ocular lens was also increased towards other substrates such as p-nitrobenzyl chloride and ethacrynic acid. In the rat lens, two isoenzymes of GSH S-transferase (pI 8.0 and 6.1) are present, and both of these isoenzymes are induced by BHT treatment. The quantification of GSH S-transferase protein in the control and the BHT-treated rat lenses indicates that the increase in GSH S-transferase activity in the ocular lens is due to the increased enzyme protein and not due to the activation of the enzyme. A significant increase in glutathione (acid soluble thiol) levels and glutathione reductase activity was also observed in the lenses of rats treated with BHT. Glutathione peroxidase activity and the enzymes of mercapturic acid pathway except GSH S-transferase remained unaltered by the BHT treatment.     

白内障术后眼内炎药物预防研究进展

白内障术后眼内炎是一种少见但破坏性极大的并发症。预防眼内炎的方式多种多样,其中术前应用聚维酮碘（povidone iodine,PVI）,术毕前房注射抗生素如万古霉素、头孢呋辛和氟喹诺酮类药物,以及围手术期局部抗生素应用是预防眼内炎的主要方式。本文就白内障术后眼内炎的流行病学、危险因素、致病因素及药物预防的研究进展作一综述。     

Age-related changes in the kinetics of human lenses: prevention of the cataract

The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina and, by changing shape, it adjusts focal distance (accommodation). The three classes of structural proteins found in the lens are α, β, and γ crystallins. These proteins make up more than 90% of the total dry mass of the eye lens. Other components which can be found are sugars, lipids, water, several antioxidants and low weight molecules. When ageing changes occur in the lens, it causes a gradual reduction in transparency, presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the eye. The main changes that occur with aging are: 1) reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2) crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3) production of advanced glycation end products (AGEs), lipid accumulation, reduction of reduced glutathione content and destruction of ascorbic acid. Even if effective strategies in preventing cataract onset are not already known, good results have been reached in some cases with oral administration of antioxidant substances such as caffeine, pyruvic acid, epigallocatechin gallate (EGCG), α-lipoic acid and ascorbic acid. Furthermore, methionine sulfoxide reductase A (MSRA) over expression could protect lens cells both in presence and in absence of oxidative stress-induced damage. Nevertheless, promising results have been obtained by reducing ultraviolet-induced oxidative damage.     

阿司匹林对半乳糖性白内障抑制作用的实验研究

目的观察阿司匹林对大鼠半乳糖性白内障的抑制作用。方法将60只Wistar大鼠分为3组：半乳糖组每日腹腔注射80%的D-半乳糖（20mL/kg）,连续10d,制成白内障动物模型;阿司匹林组同半乳糖组处理的同时每日给予阿司匹林混悬液150mg/kg灌胃至实验结束;对照组无特殊处理。实验前及造模起第3、6、10、14、20天行裂隙灯显微镜观察晶状体情况并拍照;造模起第5天各组随机处死8只大鼠,右眼晶状体匀浆检测超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-PX）、过氧化氢酶（CAT）的活性,左侧晶状体行扫描电镜观察并定量分析。结果对照组晶状体始终透明,实验第3、6、10、14、20天阿司匹林组白内障的发生率分别为0、25%、41.67%、58.33%、83.33%,大多数为囊泡初期,而半乳糖组第3天白内障发生率达65%,第6天后晶状体均发生混浊,最终发展为成熟期白内障;实验第5天扫描电镜下见对照组组织结构正常,半乳糖组损伤严重,阿司匹林组损伤较轻微;与对照组比较,半乳糖组SOD、GSH-PX、CAT活性明显降低（P〈0.05）,阿司匹林组各酶活性强于半乳糖组（P〈0.05）。结论阿司匹林能增强晶状体中SOD、GSH-PX、CAT的活性,对大鼠半乳糖性白内障有抗氧化作用,从而延缓早期白内障的发生发展。     

糖基化在白内障发病中的作用和防治对策

晶状体蛋白质糖基化在白内障发生、发展中起的作用已被长期关注。本综述从糖基化的概念、晶状体蛋白的糖基化、晶状体酶和受体的糖基化3方面,系统论述了糖基化的作用机制及其在年龄相关性和糖尿病性白内障形成中的重要作用,并介绍了抑制糖基化的方法,如AGEs形成抑制剂、AGEs交联阻断剂,这些具有针对性的治疗方法为白内障的治疗提出了有效可行的指导依据。     

Advances in cataract surgery

Cataract surgery is a technique described since recorded history, yet it has greatly evolved only in the latter half of the past century. The development of the intraocular lens and phacoemulsification as a technique for cataract removal could be considered as the two most significant strides that have been made in this surgical field. This review takes a comprehensive look at all aspects of cataract surgery, starting from patient selection through the process of consent, anaesthesia, biometry, lens power calculation, refractive targeting, phacoemulsification, choice of intraocular lens and management of complications, such as posterior capsular opacification, as well as future developments. As the most common ophthalmic surgery and with the expanding range of intraocular lens options, optometrists have an important and growing role in managing patients with cataract.     

Evaluation of the effectiveness of Quinax in the prevention of the development of senile cataract

The authors evaluated the efficacy of Quinax in 4 groups of patients with cataract. An observation of--on the average--5 years duration showed that systematic application of the drug prevents the development of the early senile cataract and distinctly slows down the progress of the disease in the group of patients without the risk factors. Non systematic application of the compound also slows down the progress of the condition in the group of early cataract. The drug was ineffective in patients with an advanced diabetic cataract.     

儿童白内障的治疗进展

儿童白内障是儿童致盲的重要原因，儿童白内障的治疗困难且富有挑战。随着现代白内障显微手术技术的发展和儿童白内障治疗观念的改变，儿童白内障的研究取得了一些进展。本文就儿童白内障治疗的时机、手术方法、材料及术后治疗等方面进行综述。     

A role for glutathione and glutathione reductase in control of corneal hydration

We have assessed the importance of the glutathione redox system of the corneal endothelial cells in the control of stromal hydration. The ability of freshly isolated corneas to maintain normal hydration during perfusion, while the activity of glutathione reductase was inhibited with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), was tested under a number of conditions. BCNU at 125 μm led to mild swelling and at 500 μm to more severe swelling. Swelling was also severe when 50 μm H₂O₂ was added together with 125 μm BCNU. The concentration of total glutathione (GSH + GSSG) in the endothelia of these corneas was decreased and the fraction found in the oxidized form was higher than in controls without BCNU. Glutathione reductase activity was inhibited in the perfused endothelia by 90%. With the addition of 0·5 mm GSSG during perfusion, swelling due to 125 μm BCNU was at a slightly lower rate and reductase activity was inhibited only 79%. Complete proteetion was afforded against 125 μm BCNU induced swelling by 1·0 mm GSH, corneas maintaining normal thickness for over 4 hr. The endothelial surface of the perfused corneas was shown by seanning electron microscopy to be little disturbed by the low concentration of BCNU, but at high concentration, or with H₂O₂ added, the cells were collapsed and had a heavily pitted appearance. We conclude that when the cornea is under oxidative stress (e.g. in the presence of H₂O₂) a rapid turnover of endothelial GSH via glutathione reductase and the hexose monophosphate shunt is required. Under conditions of less stress, the reduced need for GSH to counteract oxidative threats can be supplied either exogenously or by the partially inhibited reductase.     

激光乳化白内障摘除术研究进展

超声乳化白内障摘除术虽具有许多优点，但也存在许多不足，通过对激光的认识和了解，使其有可能应用于白内障手术，Nd：YAG激光较超声乳化白内障摘除术更加安全，对局部组织无损伤，手术时切口更小，手术后散光轻，操作简单。这一技术将使白内障手术效果更趋于完美。     

咖啡因预防白内障发生的研究进展

咖啡因又称1, 3, 7-三甲基黄嘌呤,是一种生物碱,其在神经病学、内科学、妇产科学以及儿科学等领域被广泛研究。近年来,眼科领域对咖啡因也有了一些新的认识。白内障作为人类第一大致盲眼病,目前手术是其唯一根治的方法,部分研究发现咖啡因可以通过抗氧化及抑制细胞凋亡等作用来预防白内障的发生。鉴于此,咖啡因与白内障的关系值得进一步深入研究。笔者就咖啡因在预防白内障发生中的作用机制进行探讨,以期为防治白内障提供新的理论依据。     

Nutritional supplementation for type 2 diabetes: a systematic review

The role of nutritional supplementation is of increasing interest with regard to ocular disease. Randomised controlled trials have demonstrated the effectiveness of supplementation for age‐related macular degeneration, and formulations are now being developed for use by people with diabetes and diabetic retinopathy. The aim of this review was to synthesise the evidence for use of nutritional supplementation in type 2 diabetes. MEDLINE and EMBASE databases were searched using a systematic approach. Only double‐masked randomised controlled trials were selected. A total of 50 trials were identified as suitable for inclusion. The potential role of alpha‐lipoic acid, chromium, folic acid, isoflavones, magnesium, Pycnogenol^®, selenium, vitamin C, vitamin E, and zinc in the treatment of type 2 diabetes is discussed. The review of trials identifies positive effects of these nutrients on various outcome measures relating to insulin resistance and cardiovascular factors. Chromium was the most studied supplement, accounting for 16 of the 50 trials. A majority of the trials found a positive effect of chromium on fasting plasma glucose. Isoflavones were found to have a positive effect on insulin resistance and cardiovascular outcome measures, but only when combined with soy proteins. Vitamin E is reported to reduce oxidative stress at levels of 200 mg day^?1 or more.     

白内障术后角膜病变治疗的新进展

白内障患者晶状体超声乳化术后的角膜水肿、干眼、角膜内皮功能失代偿致大泡性角膜病变等严重影响着患者满意度和视觉质量。长期以来,穿透性角膜移植是角膜内皮功能失代偿患者视力恢复的有效方法,但角膜供体缺乏及移植后角膜内皮细胞密度降低等问题仍然无法解决。近年来,角膜内皮移植、局部角膜后弹力层撕除、人工培养角膜内皮细胞植片的移植、Rho激酶抑制剂调节角膜内皮细胞增殖等方面的进展和新手段,为白内障术后角膜内皮功能失代偿患者的治疗带来新思路。