玻璃体切割术后晶状体酶活性的变化

目的观察玻璃体切割术后晶状体酶活性的变化,探讨玻璃体切割术后白内障的发病机制。方法新西兰白兔8只（16只眼）分为2组,左眼为玻璃体切割组,行经睫状体扁平部次全玻璃体切割术,右眼为正常对照组。定期观察晶状体混浊情况,5个月后取出晶状体行Na^＋-K^＋-ATP酶、过氧化氢酶和谷胱甘肽还原酶活性检测。结果5个月后,玻璃体切割组晶状体在透明度和组织形态学上与正常对照组差异无统计学意义,玻璃体切割组与正常对照组相比,Na^＋-K^＋-ATP酶、过氧化氢酶和谷胱甘肽还原酶活性分别下降了56％、17％和5％,差异均有统计学意义（P〈0．05）。结论玻璃体切割术可使成年兔晶状体发生生物化学改变,对研究玻璃体切割术后白内障的发生发展机制有重要的指导意义。     

丙酮酸对糖尿病大鼠视网膜氧化损伤及超微结构的影响

目的:研究糖尿病大鼠视网膜病变过程中视网膜组织学和氧化应激的变化,以及丙酮酸的对抗作用。方法:将80只Wistar大鼠分成3组:对照组(20只),模型组(30只),治疗组(30只)。模型组和治疗组用STZ诱导糖尿病,治疗组在大鼠饲料和饮水中添加2%丙酮酸。观察大鼠的血糖、体质量变化,并在造模后12wk观察3组大鼠视网膜组织中GSH-Px、MDA和Na+-K+-ATP酶水平及其超微结构改变。结果:模型组和对照组相比,体质量显著下降,视网膜中GSH-Px和ATP酶活性显著下降,MDA水平显著升高,视网膜超微结构有显著改变;治疗组和模型组相比,血糖没有显著改变,视网膜组织中GSH-Px和ATP水平升高,MDA水平下降,视网膜超微结构病变相对较轻。结论:丙酮酸可以减轻氧化应激反应,改善视网膜的能量代谢,延缓视网膜病变的发展。     

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。     

茶多酚对体外培养鼠晶状体抗氧化损伤作用的研究

目的:观察茶多酚(tea polyphenols,TP)对氧化损伤鼠晶状体的形态学及抗氧化系统的变化,研究其对晶状体氧化损伤的保护作用.方法:采用体外培养鼠晶状体的氧化损伤模型,设置正常对照组、氧化损伤(H2O2)组和TP(H2O2+TP)组,分别于12,24,48h后观察各组晶状体的混浊情况,并检测各组晶状体的抗氧化酶系统中的超氧化物歧化酶(SOD)及谷胱甘肽过氧化物酶(GSH-Px)活性以及脂质过氧化反应终产物丙二醛(MDA)的含量.结果:正常对照组晶状体均保持透明,未见白内障形成;H2O2组大鼠离体晶状体随作用时间的延长,晶状体的混浊程度逐渐明显增加;TP组的晶状体混浊较H2O2组明显减轻,白内障形成不明显.晶状体混浊相对灰度值组间比较,差异有统计学意义(P<0.05).H2O2组大鼠晶状体组织中MDA 含量较对照组明显增高(P<0.05),而GSH-Px和SOD明显下降(P<0.05),TP组与H2O2组相比,其晶状体中MDA降低(P<0.05),但仍高于对照组,而GSH-Px和ATP含量明显升高,差异均有统计学意义(P<0.05).结论:TP可提高氧化损伤晶状体的抗氧化能力,降低脂质过氧化物水平,从而延缓白内障的发生和发展,为临床白内障的诊疗提供了新的理论基础.     

原发闭角青光眼病人血谷胱甘肽过氧化物酶过氧化氢酶活力过氧化脂质含量测定

测定了50例全血谷胱甘肽过氧化物酶(GSH—Px)、过氧化氢酶(CAT)活力及血清过氧化脂质《LPO)含量。其中原发闭角青光眼23例,对照组27例。结果表明:原发闭角青光眼组全血GSH-Px及CAT活力明显低于对照组(P<0.001),而血浆LPO水平明显高于对照组(P<0.01),慢性闭角青光眼则更明显。自由基可能参与了原发闭角青光眼的病理过程。     

小切口非超声乳化青光眼白内障联合手术疗效观察

目的:探讨小切口非超声乳化白内障摘出人工晶状体植入联合小梁切除术治疗青光眼并发白内障的疗效。方法:回顾分析32例32眼行小切口非超声乳化白内障摘除人工晶状体植入联合小梁切除术治疗慢性闭角型青光眼并发白内障患者的临床资料。结果:术后随访6～9(平均7.3)mo,患者术后最佳矫正视力≥0.3者27眼(84%),术后所有患者眼压控制正常,平均13.50±5.30mmHg,功能性滤泡者28眼(88%),术中术后均无严重并发症。结论:小切口非超声乳化白内障囊外摘除人工晶状体植入联合青光眼小梁切除术是治疗慢性闭角型青光眼并发白内障的一种安全、有效、经济的方法。     

三联术治疗闭角型青光眼合并白内障

目的:评价小切口非超声乳化人工晶状体植入联合小梁切除术治疗闭角型青光眼合并白内障的临床疗效。方法:对20例20眼闭角型青光眼合并白内障采取小切口非超声乳化人工晶状体植入联合小梁切除术进行治疗,术后随访3mo。结果:术后视力较术前提高者占90%,术后1wk眼压全部在正常范围,无严重并发症发生。结论:小切口非超声乳化人工晶状体植入联合小梁切除术可有效治疗闭角型青光眼合并白内障。     

刀豆蛋白A条件化培养基对体外培养兔角膜内皮细胞Na^＋-K^＋-ATP酶的作用

目的 研究刀豆蛋白A(ConA)条件化培养基对体外培养兔角膜内皮细胞膜表面Na+-K+-ATP酶的分布及其酶活性的影响.方法 超微量ATP酶试剂盒测定原代培养兔角膜内皮细胞细胞膜表面Na+-K+-ATP酶的活性,并对ConA条件化培养基作用下不同生长周期(5、7、10 d)细胞Na+-K+-ATP酶的活性进行测定;免疫酶组织化学电镜下观察不同培养基作用下体外培养角膜内皮细胞膜表面Na+-K+-ATP酶的分布.结果 ConA条件化培养基组兔角膜内皮细胞Na+-K+-ATP酶活性明显高于无ConA组(P＜0.01),原代细胞生长7～10 d时Na+-K+-ATP酶活性最高(P＜0.01).单层兔角膜内皮细胞膜外侧可见Na+-K+-ATP酶阳性反应.在ConA条件化培养基处理组,其阳性反应物较多、致密;而在无ConA组则阳性反应物较少、疏松.结论 体外原代培养角膜内皮细胞在7～10 d时,Na+-K+-ATP酶活性最高.ConA条件化培养基可提高兔角膜内皮细胞Na+-K+-ATP酶活性.     

原发性闭角型青光眼合并白内障的术式选择

目的:探讨原发性闭角型青光眼合并白内障的手术方式选择.方法:选取闭角型青光眼合并白内障患者90例96眼,根据房角粘连程度及病程长短,非随机选择施行超声乳化+人工晶状体植入术(Phaco+IOL)、超声乳化+人工晶状体植入联合虹膜周切手术(Phaco+ IOL+ PLI)、超声乳化+人工晶状体植入联合小梁切除术(Phacotrab+ IOL),观察手术前后的视力、眼压、前房轴深、滤过泡,随访时间为1 mo.结果:三种手术方式治疗青光眼合并白内障,术后视力均显著提高(P＜0.05)、眼压明显降低(P＜0.05),术后1wk;1 mo三组之间眼压比较无显著差异.结论:微切口透明角膜超声乳化及联合手术治疗青光眼手术是安全的.房角粘连＜90°可行超声乳化联合人工晶状体植入;90°＜房角粘连为＜180°行超声乳化联合人工晶状体植入+联合周边虹膜切除术;如果病程长且房角粘连＞180°,考虑行超声乳化联合人工晶状体植入+小梁切除术.     

改良术式治疗白内障合并青光眼的疗效

目的:探讨改良小切口非超声乳化白内障摘除人工晶状体植入联合小梁切除术治疗白内障合并青光眼的临床疗效。方法:随机选取我院在2008-03/2011-01收治的135例白内障合并青光眼患者,随机分为两组,一组采用改良小切口非超声乳化白内障摘除人工晶状体植入联合小梁切除术治疗(观察组68例),另一组采用传统手术治疗(对照组67例),回顾性分析两组患者的临床效果。结果:观察组患者术后1wk;3mo的视力良好率分别为92.6%,88.2%;眼压良好率分别为98.5%,95.6%;观察组患者术后发生角膜水肿、虹膜损伤以及前房炎症等并发症发生率为5.9%,与对照组比较,经统计分析,P均<0.05,差异具有显著性。结论:改良小切口非超声乳化白内障摘除人工晶状体植入联合小梁切除术与传统手术比较,极大的提高了患者的治疗效果以及手术安全性,是较为安全可靠的治疗白内障合并青光眼的手术方式。     

年龄对水合氯醛诱导的小鼠可逆性晶状体混浊及Na+-K+-ATP酶表达的影响

目的：探究年龄对水合氯醛诱导的小鼠急性可逆性晶状体混浊及Na⁺-K⁺-ATP酶表达的影响。

方法：青年(3月龄)和老年(24月龄)C57BL/6小鼠各12只,4%水合氯醛(400mg/kg)腹腔注射诱导急性可逆性晶状体混浊。在注射后10、20、30、45、60、90、120、150min分别应用裂隙灯观察晶状体混浊程度,根据晶状体混浊评价系统记录混浊程度分级情况并拍照。苏木素-伊红(HE)染色观察晶状体病理改变,免疫组织化学染色检测晶状体Na⁺-K⁺-ATP酶表达。

结果：水合氯醛注射后两组小鼠晶状体混浊和消退过程相似,但青年组小鼠晶状体混浊出现早、持续时间略长,混浊厚重,呈乳白色; 老年组小鼠晶状体混浊出现晚,持续时间略短,混浊轻薄,呈薄雾状。HE染色显示水合氯醛注射后晶状体上皮细胞(LECs)下皮质聚集大量水泡,浅层晶状体纤维细胞结构紊乱。免疫组织化学染色显示LECs及纤维Na⁺-K⁺-ATP酶的表达呈现阳性,水合氯醛注射前青年组和老年组小鼠LECs中Na⁺-K⁺-ATP酶表达较弱,注射后45min LECs中Na⁺-K⁺-ATP酶的表达上调,且老年组小鼠LECs的Na⁺-K⁺-ATP酶上调更为显著。

结论：年龄影响水合氯醛诱导小鼠急性可逆性晶状体混浊,Na⁺-K⁺-ATP酶参与水合氯醛诱导的晶状体混浊。     

A rabbit model to study biochemical damage to the lens after vitrectomy: Effects of N-acetylcysteine

The purpose of the present study was to determine whether the biochemical effects of vitrectomy can be studied in rabbits and to assess the possible protective effects of N-acetylcysteine on the lens following vitrectomy. Twenty-four New Zealand rabbits (2.3-2.4 kg) were divided into three groups of eight each. Left eyes underwent vitrectomy surgery. Unoperated right eyes served as controls. Equal numbers of treated eyes were not injected, injected with 20 mM N-acetylcysteine, or 100 mM N-acetylcysteine immediately after vitrectomy. Lens transparency was monitored by slit-lamp biomicroscopy pre- and post-vitrectomy. A series of biochemical measurements were performed on lenses five months after vitrectomy. No significant differences in lens transparency or structure were observed in the three groups of lenses. However, vitrectomy was associated with significantly decreased activity of Na⁺-K⁺-ATPase and catalase. Compared with the group not treated with N-acetylcysteine, catalase activity was increased significantly in the group treated with 20 mM N-acetylcysteine. The level of glutathione and the activities of Na⁺-K⁺-ATPase and glutathione reductase were also higher in the two N-acetylcysteine-treated groups than in the untreated group, although these differences did not reach statistical significance. For all measured parameters, the effect of 20 mM N-acetylcysteine appeared to be better than 100 mM N-acetylcysteine, although these differences were not statistically significant. From these results, we gather that vitrectomy is associated with long-term decreases in enzyme activity in the lens. Injection of N-acetylcysteine into the vitreous cavity protects against some of these changes. Antioxidants like N-acetylcysteine may slow or prevent post-vitrectomy cataracts.     

The alpha1 isoform of the Na+/K+ ATPase is up-regulated in dedifferentiated progenitor cells that mediate lens and retina regeneration in adult newts

Adult newts are able to regenerate their retina and lens after injury or complete removal through transdifferentiation of the pigmented epithelial tissues of the eye. This process needs to be tightly controlled, and several different mechanisms are likely to be recruited for this function. The Na⁺/K⁺ ATPase is a transmembrane protein that establishes electrochemical gradients through the transport of Na⁺ and K⁺ and has been implicated in the modulation of key cellular processes such as cell division, migration and adhesion. Even though it is expressed in all cells, its isoform composition varies with cell type and is tightly controlled during development and regeneration. In the present study we characterize the expression pattern of Na⁺/K⁺ ATPase α1 in the adult newt eye and during the process of lens and retina regeneration. We show that this isoform is up-regulated in undifferentiated cells during transdifferentiation. Such change in composition could be one of the mechanisms that newt cells utilize to modulate this process.     

Contribution to Ischemic Injury of Rat Optic Nerves by Intracellular Sodium Overload

Ischemic insult to axons of retinal ganglion cells (RGCs) is believed to contribute significantly to preferential loss of RGCs in glaucoma. In this study, we characterized the role of intracellular Na⁺ overload in ischemic injury of acutely isolated rat optic nerves by evaluating electrically elicited compound action potentials (CAPs) from the optic nerves. Under control conditions, robust and stable CAPs can be recorded for more than 5 h. One hour of oxygen and glucose deprivation (OGD) that simulates ischemia, virtually eliminated the CAP. Upon returning to control conditions, the CAP gradually recovered. Maximum recovery (35% of control) was obtained by 1 h after returning to normal oxygenated Ringer. When a rapidly reversible Na⁺ channel blocker, that completely blocked the CAP under control conditions, was present during OGD, the recovery of the CAP was significantly enhanced to 65% of control. When the Na⁺ was replaced with either choline or Li⁺ in the Ringer during OGD, CAP recovery was significantly enhanced (65–70% of control). Removing Ca⁺⁺ from the Ringer (plus 5 mM EGTA) provided even better preservation of the CAP following OGD (90% of control). Our results are consistent with the hypothesis that intracellular Na⁺ overload appears to play a significant role in ischemic injury of optic nerves. This Na⁺ overload may depend at least partially upon Ca⁺⁺ influx from the extracellular space.     

Expression of the Na+-K+-2Cl(-)-cotransporter 2 in the normal and pressure-induced ischemic rat retina

Purpose

To evaluate the expression of the Na⁺-K⁺-2Cl^--cotransporter 2 (NKCC2) in the ischemic rat retina.

Methods

Retinal ischemia was induced by pressures 90 to 120 mmHg, above systemic systolic pressure. Immunohistochemistry and western blot analysis were performed.

Results

NKCC2 is expressed in the normal retina and its expression is increased by ischemia caused by intraocular pressure elevation. NKCC2 immunoreactivity was observed mainly in axon bundles of ganglion cells and horizontal cell processes in the retina. NKCC2 expression continuously increased with a peak value 3 days (to 415% of normal levels) after ischemic injury, and then gradually decreased to 314% of controls until 2 weeks post injury. The mean density of NKCC2-labeled ganglion cells per mm² changed from 1,255 ± 109 in normal retinas to 391 ± 49 and 185 ± 37 at 3 days and 2 weeks after ischemia, respectively (p < 0.05), implying cell death of ganglion cells labeled with NKCC2.

Conclusions

Taken together, these results suggest that NKCC2, which is expressed in retinal ganglion and horizontal cells, may contribute to cell death by ischemic injury in the retina, although the molecular mechanisms involved remain to be clarified.     

Regulatory Volume Increase of Human Non-pigmented Ciliary Epithelial Cells

Cells (ODM/SV40) derived from human non-pigmented ciliary epithelial cells were studied by electronic cell sizing. After transiently suspending the cells in hypotonic solution, isotonicity was restored by addition of sucrose. The cell volumes (v_c) initially fell below those of control isotonic suspensions, and subsequently increased towards the baseline level. This secondary increase inv_cis termed the regulatory volume increase (RVI). Results obtained with ionic substitutions and transport inhibitors indicate that four ionic mechanisms can support the RVI in these cells: coupled Na⁺/H⁺and Cl⁻/HCO₃⁻antiports, a Na⁺/Cl⁻symport, a Na⁺/K⁺/2Cl⁻symport, and a Na⁺⁻channel in parallel with a Cl⁻/HCO₃⁻antiport. Arachidonic acid metabolites regulate the RVI very differently from their effects on the regulatory volume response (RVD) of the same cells to cell swelling. Prostaglandin E₂(PGE₂), leukotriene (LTD₄) and the PKC-inhibitor staurosporine all inhibit the RVI. Blockade of the cyclooxygenase, lipoxygenase and epoxygenase pathways of arachidonic acid metabolism [with 5,8,11,14-eicosatetraynoic acid (ETYA)] produces a net acceleration of the RVI. In contrast, PGE₂and staurosporine stimulate, LTD₄has no effect, and ETYA inhibits the RVD. We suggest that knowledge of the ionic mechanisms and intracellular signalling underlying the RVI phenomenon may provide a basis for reducing the rate of net aqueous humor formation by increasing the rate of reabsorption of fluid from the aqueous humor into the non-pigmented ciliary epithelial cells.     

Biochemical and immunological characterization of Na+, K+-ATPase from lens membrane and other tissues

Two-dimensional mapping of radioiodinated peptides from the purified α-subunit of Na⁺, K⁺-ATPase has been used to identify the α-subunit from fiber cell membrane of chick lens. Purified α-subunits from the electric organ of eel, the rectal gland of spiny dogfish, the outer medulla of dog kidney, and the chick brain all possess molecular weights of approximately 97 000. In addition, they all share at least three radioiodinated peptides in common. Two of these peptides have been localized to the C-terminal half of the molecule that is strongly associated with the lipid bilayer. The similarities of Na⁺, K⁺-ATPases from these tissues have been used to identify the α-subunit of the Na⁺, K⁺-ATPase from fiber cell membrane of chick lens. Peptide mapping of the chick lens 97 000 dalton component indicates homology with all α-subunits of all Na⁺, K⁺-ATPases studied, with closest homology with the α-subunits from chick brain. Antisera made against the purified holoenzyme of dog kidney inhibits Na⁺, K⁺-ATPase activity of both dog kidney and chick lens fiber membrane. This antisera specifically binds to components of approximately 97 000 daltons of chick lens membrane. Together, these results demonstrate that the α-subunit of Na⁺, K⁺-ATPase from chick lens membrane is comprised of polypeptides of approximately 97 000 daltons that share biochemical and antigenic homology with the Na⁺, K⁺-ATPase of other tissues and species.     

Phosphorylation of H2O2-treated lens Na+, K+-ATPase

It has been previously shown that H₂O₂ inhibits lens ⁸⁶Rb influx and results in modification of Na⁺,K⁺-ATPase with respect to ATP hydrolysis. The effect of H₂O₂ on ATP hydrolysis was further investigated using [γ-³²P]-ATP to examine the Na⁺,K⁺-ATPase phosphorylated intermediate. A Na⁺-dependent phosphorylated polypeptide with an apparent molecular weight of approximately 100 000 was detected in all lens preparations, irrespective of H₂O₂ treatment. Similar results were observed for partially purified Na⁺,K⁺-ATPase from bovine kidney, porcine brain and canine kidney.