Nitric oxide levels of aqueous humor after photorefractive keratectomy

PURPOSE: To measure the nitric oxide (NO) levels of aqueous humor in rabbits after photorefractive keratectomy (PRK) and to evaluate the alterations of NO levels according to the PRK surgery steps, ablation depth, and time. METHODS: Fifty eyes of 25 New Zealand white rabbits were included in the study. One eye was later randomly excluded from the study in order to equalize the number of eyes in groups. Eyes were divided into seven groups, each comprising seven eyes: unwounded control (Group 1), epithelial scrape (Group 2; aqueous humor samples taken at the 4th hour), superficial PRK (Group 3; samples taken at the 4th hour), deep PRK (Group 4; samples taken at the 4th hour), epithelial scrape (Group 5; samples taken at the 24th hour), superficial PRK (Group 6; samples taken at the 24th hour), and deep PRK (Group 7; samples taken at the 24th hour). The corneal epithelium was mechanically removed in surgical groups. The authors performed superficial corneal ablation (59 microm) in Groups 3 and 6 and deep corneal ablation (99 microm) in Groups 4 and 7. Aqueous humor samples were taken at the 4th hour (Groups 2-4) or 24th hour (Groups 5-7) after corneal surgeries. NO measurements were performed indirectly by using the Griess reaction with a spectrophotometer. RESULTS: Aqueous humor NO levels 4 hours after corneal surgery were statistically significantly lower than the control group (p<0.05). However, there was no difference among the surgical groups at the 4th hour (p>0.05). At the 24th hour, the deep PRK group had significantly lower NO levels than both the control group and Groups 5 and 6 (p<0.05). NO levels were normalized at the 24th hour in epithelial scrape and superficial PRK groups (p>0.05) but remained stable at lower levels in deep PRK groups (p<0.05). CONCLUSIONS: Corneal surgery caused low NO levels in aqueous humor 4 hours after surgery. However, 24 hours after surgery, NO levels normalized following epithelial scrape and superficial PRK and were stable at lower levels in the deep PRK group. Complications of deep PRK application are possibly induced by low NO existence in the aqueous humor.     

青光眼患者血清及房水一氧化氮浓度的测定

目的 测定青光眼患者血清及房水一氧化氮(NO)浓度并探讨其在青光眼发病中的作用。方法 实验患者分为青光眼组和白内障组,应用硝酸还原酶法分别测定两组患者血清及房水NO浓度。结果 两组患者血清NO浓度无显著性差异,青光眼组内各类型之间血清NO浓度亦无显著性差异。原发性开角型青光眼患者房水NO浓度较对照组及其他类型青光眼显著降低,闭角型青光眼患者房水NO浓度较对照组显著升高(P<0.01)。 结论 眼压升高可引起房水NO浓度升高,过多的NO可损伤小梁网及邻近的葡萄膜及视网膜组织。开角型青光眼患者由于房角原生型一氧化氮合成酶的减少引起房水NO浓度的降低,此可能为眼压升高的原因之一。     

急性闭角型青光眼患者血清及房水一氧化氮水平的研究

目的探讨急性闭角型青光眼(AACG)患者血清和房水中一氧化氮(NO)浓度的变化及它们与眼压的关系,并分析这些变化对青光眼发生发展可能产生的影响。方法用硝酸还原酶法测定AACG患者28例及正常人20例血清中一氧化氮的浓度,AACC;患者22例和老年性白内障患者13例房水中一氧化氮的浓度,分别对血清和房水中一氧化氮的浓度进行统计学分析。结果青光眼组的房水平均NO浓度为(61.46±4.89)μm/L,白内障组的房水平均NO浓度为(30,60±2,81)μm/l,两组均数之间的差异有显著性(P<0.01)。青光眼组血清NO平均浓度为(68.49±15.37)μm/L,正常对照组血清NO平均浓度为(72.19±10.82)μm/L,两组均数之间的差异无统计学意义(P>0.05)。结论μAACG患者房水NO浓度较白内障组明显增高,高眼压可能是导致房水NO浓度改变的关键因素。过度升高的NO对视网膜神经节细胞的毒性作用可能参与了青光眼性视神经损害的发展过程。     

Nitric oxide and cyclic GMP enhance aqueous humor outflow facility in rabbits

PURPOSE: Nitric oxide (NO) may control intraocular pressure (IOP)-regulating mechanisms physiologically and in ocular diseases such as glaucoma. The aim of the present study was to clarify whether an increase in aqueous humor outflow facility could explain the IOP-lowering effect of the NO/cyclic GMP pathway we recently described. METHODS: Test compounds were administered to anesthetized rabbits (New Zealand White, n = 6) intracamerally (5 microl) in the following doses: nitrosocaptopril 12.3 microg, captopril 10.9 microg, sodium nitroprusside (SNP) 13.1 microg and 8-Br-cGMP 22.3 microg. Outflow facility (C) was determined by the two-level constant pressure infusion method. Outflow facility, C( 1) and C(2), was measured at lower and higher pressure levels, respectively. RESULTS: Outflow facility was increased after treatment with SNP (increase in C in the experimental eye as compared to the control eye C( 1) 80% and C(2) 74%), nitrosocaptopril (C(1) 69% and C(2) 64%) and 8-Br-cGMP (C(1) 35% and C(2) 33%). Captopril had no effect on outflow facility (C(1) -12% and C(2) 2%). Blood pressure was not affected by the drugs. CONCLUSIONS: We conclude that enhancement of outflow facility by nitrosocaptopril, SNP and 8-Br-cGMP, their second messenger derivative, at least partly explains the IOP-lowering effect of NO releasing compounds.     

Lens crystallin reactive protein in the aqueous humor of cataract patients

It is well known that soluble protein decreases in the senile cataractous lens. In this report, the possibility of soluble protein leakage through the capsule into the aqueous humor was studied. Aqueous humor from cataractous patients was obtained in the operating room and analyzed by molecular sieve high performance liquid chromatography (HPLC) and electrophoretic immune blotting assay. A whole lens was obtained from a patient with lens luxation. The lens was kept in Tyrode's incubation medium and the protein leakage into the medium was also analyzed by electrophoretic immune blotting assay. beta L-crystallin reactive protein was ascertained in the aqueous humor of senile cataractous patients. Leakage of the beta L-crystallin reactive protein increased in immature and mature cataracts. The present results also demonstrated leakage of lens crystallin from the senile cataractous lens without capsular rupture.     

Correlation of aqueous humor electrolytes with serum electrolytes in cataract patients

Purpose:To correlate the aqueous humor electrolytes with serum electrolytes in patients with cataract.Methods:In this study, 348 eyes of patients undergoing cataract surgery, who had presented between 1^st January 2019 and 30^th June 2020, were included. Serum electrolytes were obtained and 0.15 ml of aqueous humor was obtained during surgery using an insulin syringe via the side port incision. Mean and standard deviation was used to analyze all the categorical and continuous data including all the electrolytes levels. Pearson’s correlation of coefficient was used to analyze the comparison between serum and aqueous humor electrolytes. Student T-test was used to compare electrolyte values between the serum and aqueous humor.Results:We observed a significant correlation of the aqueous humor electrolytes with their serum counterparts. The coefficient of correlation is 0.155, 0.44, and 0.405 for Na+, K+, and Cl−, respectively. There is also a significant increase in the aqueous humor electrolytes as compared to the serum levels.Conclusion:A significant increase in electrolytes levels in the aqueous humor of cataract patients possibly could have a role in the etiology of cataract.     

糖尿病性白内障房水中细胞因子IGF-1、bFGF和IL-6的含量测定

目的 检测糖尿病性白内障患者房水中胰岛素样生长因子-1(insulin-like growth factor-1,IGF-1)、碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)和白介素-6(interleukin-6,IL-6)的含量,分析其与糖尿病性白内障患者相关性及临床意义.方法 采用双抗体夹心酶联免疫吸附法测定71份白内障患者术前房水中IGF-1、bFGF-1和IL-6的含量.分为实验组:糖尿病性白内障患者房水38份,包括无糖尿病视网膜病变组(non-diabetic retinopathy,NDR)房水25份和伴有非增生性糖尿病视网膜病变组(non-proliferative diabetic retinopathy,NPDR)房水13份,对照组为年龄相关性白内障患者房水33份,以同样方法测定.结果 实验组患者房水中IGF-1含量(7.47±5.03)ng·L-1和bFGF含量(7.47±7.08)ng·L-1均高于对照组(4.13±2.52)ng·L-1和(3.44±2.92)ng·L-1,差异有统计学意义(P<0.01或P<0.05);IL-6含量实验组与对照组比较,差异无统计学意义(P>0.05).NDR组和NPDR组房水中IGF-1含量均高于对照组,差异有显著统计学意义(P<0.01);NDR组和NPDR组房水中bFGF含量分别为(7.44±6.59)ng·L-1和(7.52±8.22)ng·L-1,均高于对照组(P<0.05);3组间房水中IL-6含量比较,差异均无统计学意义(均为P>0.05);房水中ICF-1与bFGF之间、ICF-1与lL-6之间呈正相关性(r=0.409,P<0.01;r=0.259,P<0.05),但bFGF与IL-6之间无相关性(r=0.196,p>0.05).结论 糖尿病性白内障患者术前房水中bFGF、IGF-1含量的增加可能与高糖状态晶状体上皮细胞受损、凋亡及血-房水屏障破坏有关,房水中FGF、IGF-1和IL-6水平差异反映了不同细胞因子在不同发病阶段的参与作用,可作为治疗和预后的参考指标.     

L-Arginine-nitric oxide pathway-related metabolites in the aqueous humor of diabetic patients

PURPOSE: Nitric oxide (NO) is an important signal-transduction molecule that plays a significant role in the regulation of cardiovascular functions. In the L-arginine-NO pathway, NO synthase (NOS) converts L-arginine (L-Arg), the only known biologic substrate for NO formation, to NO and L-citrulline (L-Cit). Excessive NO production mediated by the inducible isoform of NOS has been implicated in the pathogenesis of various diseases. In the present study it was hypothesized that in vitreoretinal disorders such as diabetic retinopathy the production of L-Arg-NO pathway-related metabolites may be upregulated as a result of increased NO generation. METHODS: From 20 eyes of nondiabetic subjects and 22 eyes of diabetic patients with (n = 14) and without (n = 8) diabetic retinopathy, undiluted samples of aqueous humor were drawn before cataract surgery. Levels of L-Arg, L-Cit, and the specific NOS by-product N(G)-hydroxy-L-arginine (HOArg) were measured by high-performance liquid chromatography. RESULTS: L-Arg, L-Cit, and HOArg were detected in all aqueous humor samples from diabetic and nondiabetic patients (n = 42). Comparison of HOArg levels in nondiabetic and diabetic subjects showed significantly higher levels in diabetic patients (P = 0.002). Concentrations of HOArg were higher in samples from patients with (P = 0.005) and without diabetic retinopathy (P = 0.033) than in control subjects. No statistically significant differences were observed in L-Arg or L-Cit levels. CONCLUSIONS: Elevated levels of HOArg in the aqueous humor of diabetic patients reflect the possible role of NO as a significant factor in the regulation of retinal vascular functions and intraocular proliferative changes in diabetes mellitus in vivo. The control of intraocular NO production may constitute a potential therapeutic approach in diabetic retinopathy.     

年龄相关性白内障房水中叶黄素的含量分析

目的 测定不同程度年龄相关性白内障(age-related cataract)房水中的叶黄素(lutein)含量.方法 应用高效液相色谱法(HPLC)对34例年龄相关性白内障患者的房水标本进行叶黄素检测.结果 皮质性白内障未熟期组,皮质性白内障成熟期组和核性白内障组患者房水中的叶黄素分别为(85.42±69.90、28.24±23.86、19.65±19.33) ng/mL.皮质性白内障未熟期组房水中的叶黄素含量高于皮质性白内障成熟期组和核性白内障组,差异有统计学意义(P＜0.05),皮质性白内障成熟期组和核性白内障组患者间差异无统计学意义(P＞0.05).结论 随着年龄相关性白内障程度加重房水中的叶黄素含量减低,提示房水中的叶黄素含量与白内障形成相关,同时也为房水中叶黄素含量提供了一种手段.     

Effects of NG-nitro L-arginine and corticosteroids on aqueous humor levels of nitric oxide and cytokines after cataract surgery.

PURPOSE: To assess the efficacy of nitric oxide synthesis (NOS) inhibitor, topical steroids, and nonsteroidal anti-inflammatory drugs on aqueous levels of nitric oxide (NO) and cytokines after cataract surgery. SETTING: Research Laboratory, Inonu University Turgut Ozal Medical Center, Malatya, Turkey. METHODS: Fifteen rabbits had intercapsular phacoemulsification and were randomly divided into 3 treatment groups: Group 1 was treated with topical prednisolone acetate 1% drops 5 times a day for 1 week; Group 2, flurbiprofen 0.03% drops 5 times a day for 1 week; Group 3, a 0.1 cc subconjunctival injection of NG-nitro L-arginine (L-NAME) (150 mg/kg) 1 day and 3 days after surgery. Three rabbits serving as controls received a subconjunctival injection of an equal volume of balanced salt solution (BSS) at the same times as the L-NAME injections. Aqueous humor specimens were collected from each eye to determine NO and cytokine levels including interleukin-1-beta (IL-1 beta), interleukin-2R (IL-2R), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha). RESULTS: The levels of IL-1 beta and IL-6 were higher in Group 2 and the control group than in Groups 1 and 3 at all times. The differences were not statistically significant (P < .05). Nitric oxide and TNF-alpha levels in Groups 1 and 3 were significantly lower than in Groups 2 and the controls 1, 3, and 7 days postoperatively (P < .05). CONCLUSION: These findings suggest a strong inhibitory effect of NOS inhibitors and corticosteroids on aqueous levels of TNF-alpha and NO and no inhibitory effect on IL-1 beta and IL-6 levels after cataract surgery.     

老年性白内障患者房水中氧化应激物质含量的测定

目的测定老年性白内障患者房水中的氧化应激物质的含量。方法收集59例老年性白内障患者并测定患者房水中蛋白质的浓度,超氧化物歧化酶(superoxide dis-mutase,SOD)、过氧化氢酶(catalase,CAT)、谷胱甘肽过氧化物酶(glutathione-peroxide,GSH-PX)的活性。结果 59例患者中术前蛋白质的浓度、SOD、CAT、GSH-PX的活性平均分别为(2.572±0.176)g·L-1、(0.156±0.180)U·mL-1、(1.118±0.015)U·mL-1、(0.062±0.022)U·mL-1,术前对数视力是0.402±0.070。随着白内障的核硬度的分级增加可以观察到蛋白质的浓度、SOD、GSH-PX的活性显著性增加(P<0.05),没有发现明显年龄相关性氧化应激物质的差异。结论随着白内障核硬度的分级增加,蛋白质浓度、SOD、GSH-PX的活性显著性增加,而不是随着患者的年龄增加而增加。表明白内障进展中大分子物质蛋白质、SOD是从晶状体囊分泌的。     

炎性因子在乙肝病毒携带的白内障患者房水中的表达及意义

目的评估乙肝病毒携带[HBV(+)]的白内障患者和正常白内障患者房水中炎性因子的差异。设计实验研究。研究对象18例HBV(+)的白内障患者及18例正常白内障患者的房水。方法所有研究对象在白内障手术时采集房水样本,采用人细胞因子抗体阵列检测技术(Ray-Biotech公司)对40种细胞因子进行检测。主要指标房水40种炎性因子含量。结果在检测的40种炎性因子中,HBV(+)白内障患者和正常白内障患者房水中GM-CSF(0.559±0.134 pg/ml,0.768±0.195 pg/ml)、IL-5(1.285±0.664 pg/ml,1.854±0.896 pg/ml)、IL-7(5.076±1.112 pg/ml,6.298±1.435 pg/ml)、IL-17(2.643±1.050 pg/ml,3.643±1.659 pg/ml)、PDGF-BB(0.367±0.297 pg/ml,0.169±0.286 pg/ml)、TNFα(6.912±2.697 pg/ml,3.191±3.462 pg/ml)、TNFβ(28.307±12.954 pg/ml,17.424±12.741 pg/ml)7种因子的含量存在显著性差异(P均<0.05)。结论本小样本研究显示,HBV(+)白内障患者房水中炎性因子PDGF-BB、TNFα、TNFβ表达较正常白内障患者升高,GM-CSF、IL-5、IL-7、IL-17降低。PDGF-BB、TNFα、TNFβ表达升高可能是HBV(+)白内障患者较正常白内障患者术中疼痛更敏感的原因。     

Anaphylatoxin levels in human aqueous humor

Radioimmunoassay was used to measure levels of C3a, C4a, and C5a in aqueous humor from 13 normal eyes, 8 noninflamed eyes with a history of surgery or inflammation, and 14 eyes with anterior uveitis. The authors were unable to measure levels of C3a, C4a, or C5a in normal aqueous humor. In noninflamed aqueous humor from eyes with a history of surgery or inflammation, the authors were unable to measure levels of C4a or C5a, but were able to measure low levels of C3a in 3/8 patients. In aqueous humor from eyes with anterior uveitis, the authors were able to measure levels of C3a in all 14 patients, C4a in 9/14 patients, and C5a in 5/14 patients. Patients with severe anterior uveitis had higher levels of C3a than those with moderate anterior uveitis. The higher ratios of anaphylatoxin to protein levels in inflamed aqueous humor, when compared to normal plasma or noninflamed aqueous humor, suggested that complement was being activated by either the classical or alternative pathways in inflamed aqueous humor. Measurable levels of C3a without detectable C4a in five patients with anterior uveitis suggested alternative pathway activation of complement.     

Significant variation of the elevated nitric oxide levels in aqueous humor from patients with different types of glaucoma

Though several studies have shown that the biochemical function of nitric oxide (NO) in the eye might play an important role in the regulation of intraocular pressure (IOP), local control of ocular blood flow and loss of retinal ganglion cells by apoptosis, it is unclear whether the role of NO is similar in the pathogenesis of different kinds of glaucoma: primary open-angle glaucoma (POAG), chronic closed-angle glaucoma (CCAG) and neovascular glaucoma (NVG). To further explore this issue, we measured the concentrations of NO in aqueous humor and plasma samples from patients with POAG (n = 31), CCAG (n = 76), NVG (n = 8) and cataract (n = 30). All of the NVG patients suffered from severe proliferative diabetic retinopathy, while other patients were free of any other systemic disease. The NO levels in both aqueous humor and plasma samples were assessed by chemiluminescence assay. We found that the NO levels in aqueous humor samples were greatly varied in patients with POAG (36.2 +/- 3.3 microM), CCAG (47.7 +/- 3.4 microM) and NVG (65.8 +/- 5.4 microM), and all of them were significantly higher than in cataract patients (27.0 +/- 2.9 microM p < 0.05). Except NVG patients whose NO levels in plasma samples were highest (24.1 +/- 3.5 microM) among all groups, the plasma NO levels were not significantly different between the other glaucoma patients and the cataract patients. We therefore concluded that significant variation of the elevated NO levels in aqueous humor samples from the patients with different types of glaucoma may reflect their differences in the pathogenesis.