Pharmacokinetic and pharmacodynamic evaluation of the anti-cataract effect of eye drops containing disulfiram and low-substituted methylcellulose using ICR/f rats as a hereditary cataract model

We attempted to develop anti-cataract eye drops using disulfiram (DSF) and low-substituted methylcellulose (MC), and evaluated their anti-cataract effect in terms of the lens opacification vs. age-profile curves using a one-exponential equation. The eye drops were prepared using 0.5% DSF and 2% MC (DSF eye drops), and ICR/f rats, a recessive-type hereditary cataractous strain, were used as the experimental model. Gelation of DSF eye drops containing MC was first observed at about 35°C, close to body temperature. In in vivo transcorneal penetration experiments using rabbit corneas, only diethyldithiocarbamate (DDC) was detected in the aqueous humor, while DSF was not detected. The DDC penetration level of DSF eye drops containing MC was approximately 1.3-fold higher than that of DSF eye drops. The opacification rate constant (k) of ICR/f rat instilled with DSF eye drops with or without MC was lower, and the initial time of opacification (τ) was longer than those of ICR/f rats instilled with saline. Furthermore, the k of ICR/f rats instilled with DSF eye drops with MC was lower than that of ICR/f rats instilled with DSF eye drops without MC. In conclusion, the analysis of kinetic parameters including k and τ using a one-exponential equation provided useful information for clarifying the anti-cataract effect of eye drops. ICR/f rats instilled with DSF eye drops using a low-substituted MC-based drug delivery system demonstrated a delay in cataract development, probably resulting from an increase in the retention of DSF eye drops on the cornea.     

Adverse effects of excessive nitric oxide on cytochrome c oxidase in lenses of hereditary cataract UPL rats

The UPL rat is a newly developed hereditary cataract model. We previously found that the ATP content in UPL rat lenses decreases during cataract development, and the decrease in ATP content causes Ca(2+)-ATPase dysfunction resulting in an elevation in Ca(2+) and cataract development. In addition, we reported that the oral administration of disulfiram and aminoguanidine ameliorates the decrease in ATP content and the elevation in Ca(2+) content in UPL rat lenses. In this study, we demonstrate the effect of nitric oxide (NO) on the expression and activity of cytochrome c oxidase (CCO) in normal and UPL rat lenses during cataract development. We also determined the effects of the oral administration of disulfiram and aminoguanidine on the mRNA expression and activity of CCO and NO production in UPL rat lenses. The expression of CCO-1 mRNA in UPL rat lenses, determined by a quantitative real-time RT-PCR method, decreased during cataract development. CCO activity in UPL rat lenses also decreased with aging. On the other hand, the oral administration of disulfiram and aminoguanidine attenuated the decrease in CCO-1 mRNA expression and CCO activity. These results suggest that excessive NO causes the decrease in CCO-1 mRNA expression and CCO activity, and that the decrease in CCO may cause the decrease in ATP production in UPL rat lenses. Disulfiram and aminoguanidine may attenuate the decrease in ATP production, resulting in a delay in cataract development.     

Inhibitive effects of enhanced lipid peroxidation on Ca(2+)-ATPase in lenses of hereditary cataract ICR/f rats

Our previous studies have demonstrated that the instillation of eye drops containing disulfiram, a radical scavenger and nitric oxide synthase inhibitor, delays cataract development in ICR/f rats, and we have suggested that the production of nitric oxide (NO) and lipid peroxide (LPO) in the lens may relate to the delay in cataract development brought about by disulfiram. However, the involvement of NO and LPO in lenses of ICR/f rats during cataract development has not yet been established. In the present study, we determined changes in NO and LPO levels in lenses of ICR/f rats during cataract development. Opacification of ICR/f rat lenses started at 77 days of age, and the lenses of 91-day-old ICR/f rats were almost entirely opaque. The Ca(2+)-ATPase activity in the lenses of ICR/f rats decreased with increasing age, and an elevation in Ca(2+) content was observed in ICR/f rat lenses with the decrease in Ca(2+)-ATPase activity. NO levels in the lenses of ICR/f rats increased from 63 to 85 days of age, reaching a maximum at 77 days of age. In addition, LPO levels in the lenses of ICR/f rats also increased with increasing age. LPO levels in the lenses of 63- to 91-day-old ICR/f rats were found to be significantly higher compared with those in 22-day-old ICR/f rats. These changes of Ca(2+), Ca(2+)-ATPase, NO and LPO were attenuated by instillation of DSF eye drops. These results suggest that excessive NO may cause enhanced lipid peroxidation resulting in the inhibition of Ca(2+)-ATPase. The decrease in Ca(2+)-ATPase activity may cause the elevation in lens Ca(2+), leading to lens opacification in ICR/f rats.     

Delay in ICR/f rat lens opacification by the instillation of eye drops containing disulfiram and hydroxypropyl-beta-cyclodextrin inclusion complex

In this study, we attempted to enhance disulfiram (DSF) solubility using a 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) and hydroxypropylmethylcellulose (HPMC). We also investigated the effect of an HPbetaCD solution containing DSF and HPMC (DSF eye drops) on cataract development in ICR/f rat. The solubility of DSF increased with increasing HPbetaCD concentration, and the solubility of DSF in HPbetaCD solution containing 0.1% HPMC was approximately 20% greater than that of DSF in HPbetaCD solution without HPMC. In in vivo transcorneal penetration experiments using rabbits, only diethyldithiocarbamate (DDC) was detected (DSF was not detected) in the aqueous humor. This DSF-DDC conversion in the cornea was inhibited by treatment with a sulfhydryl (SH) inhibitor, p-mercuribenzoate and N-ethylmaleimide, in in vitro transcorneal penetration experiments using rabbit corneas. On the other hand, the instillation of 0.25% and 0.5% DSF eye drops delayed cataract development in ICR/f rats, a recessive-type hereditary cataractous strain. The present study demonstrates that DSF in HPbetaCD solution with HPMC is converted to DDC by the catalysis of proteins containing SH residues in the cornea, and this DDC may cause the delay in cataract development in ICR/f rats.     

Crystallin proteins in lenses of hereditary cataractous rat, ICR/f

ICR/f mutation in rat, an inherited disorder, is characterized by the development of cataracts. In this study, we analyzed and compared the crystallins in normal and cataractous rat lenses using gel filtration and two-dimensional gel electrophoresis, and determined the transglutaminase activities and Ca2+ content in the mutant and normal lenses. The Ca2+ content about 10-fold and the activity of transglutaminase was about 1.8-fold higher in the cataractous lenses than in the normal lenses. Analysis of the cataractous lens proteins showed a remarkable decrease in gamma-, betaB1-, betaA3-, and betaA4-crystallin content, accompanied with some increase in alpha-crystallin (or its aggregate). Higher molecular weight proteins were also observed in the cataractous lenses, with molecular masses which correspond to those of cross-linked dimers (43 to 55 kDa) of beta-crystallins. We consider that the mutation accelerates the aggregation of the crystallins, which is associated with their cross-linking by transglutaminase.     

Variation in glycosidase activity in soluble fractions in ICR/f rat lenses with the progression of cataract formation

The current study reports active glycosidases in the lens of ICR/f rats, which generate a hereditary cataract approximately 90 d after birth, and the variation in enzyme activity with cataract progression. Seven active glycosidases, beta-D-galactosidase, alpha-D-glucosidase, beta-D-glucosidase, beta-D-glucuronidase, beta-D-galactosaminidase, beta-D-glucosaminidase and alpha-D-mannosidase, were detected in ICR/f rat lenses. Of these, beta-D-glucuronidase and beta-D-galactosidase showed a tendency to increase in activity with the cataract progression. Furthermore, beta-D-glucosidase and alpha-D-mannosidase showed a transitory increase in activity at the time of cataract formation. This result suggests that several glycosidases in the lens may be involved in the hereditary cataract formation. The optimal pH and temperature of the seven active glycosidases in rat lenses were also measured in this study.     

Effect of nitric oxide synthase inhibitors on lipid peroxide formation in liver caused by endotoxin challenge

This study investigated the effect of nitric oxide on lipid peroxide formation during endotoxaemia. Nitric oxide synthase inhibitors N(G)-monomethyl-L-arginine acetate (L-NMMA, 20 mg/kg, intravenously), N(G)-nitro-L-arginine-methyl ester (L-NAME, 10 mg/kg, intravenously), and N(G)-nitro-L-arginine (L-NA, 10 mg/kg, intravenously), and a relatively selective inducible nitric oxide synthase inhibitor aminoguanidine (10 mg/kg, intravenously), did not protect against endotoxin-induced death of mice. Superoxide dismutase activity in liver 18 hr after administration of endotoxin (6 mg/kg, intraperitoneally) to L-arginine analogues (L-NMMA, L-NAME, L-NA)-treated mice was lower than in mice treated with endotoxin alone, whereas the administration of L-arginine analogues increased xanthine oxidase activity in the livers of endotoxin-injected mice compared with mice treated with endotoxin alone. In mice treated with L-arginine analogues and aminoguanidine, the levels of non-protein sulfhydryl and lipid peroxide in liver 18 hr after endotoxin injection did not show significant differences from mice treated with endotoxin alone. L-Arginine analogues and aminoguanidine had little effect on lipid peroxide formation in liver caused by endotoxin. Treatment with aminoguanidine (300 microM) significantly inhibited endotoxin-induced intracellular peroxide in J774A.1 cells, however, aminoguanidine did not affect endotoxin-induced cytotoxicity in J774A.1 cells. Our results clearly demonstrate that treatment with catalase (10 microg/ml), D-mannitol (10 mM), or superoxide dismutase (100 U/ml), has little or no effect on nitric oxide production by endotoxin (1 microg/ml)-activated J774A.1 cells. These findings suggest that nitric oxide is not crucial for lipid peroxide formation during endotoxaemia. Therefore, it is unlikely that nitric oxide plays a significant role in liver injury caused by free radical generation in endotoxaemia.     

Effect of calpain on hereditary cataractous rat, ICR/f.

The crystallins in the lenses of ICR/f mutation rat, a known hereditary cataract model, were analyzed during cataractogenesis. Opacification of the mutant lenses was found to be accompanied by changes in crystallin structure and composition, including several deletions of the N-terminals of beta-crystallins and low molecular weight alpha- crystallins. Because similar deletions were observed when the soluble fraction of normal lens protein was incubated with calpain, we considered that calpain could be related to the deletions in mutant lenses. Although measurement of the content of calpain protein by the ELISA method revealed no significant difference between mutant and normal lenses, it was found that the concentrations of Ca2+ and K+ were different between the two lenses and that calpain activity was dependent on both ion concentrations. Endogenous m-calpain in the soluble fraction from normal lenses was activated by addition of 1 mm calcium chloride in the presence of 50 mm KCl (the same concentration as in mutant lenses), and insoluble protein was found in the fraction 1 d after calpain activation. On the other hand, the presence of 120 mm KCl (the concentration in normal lenses) inhibited calpain activity and prevented this insolubilization. These results suggest that calpain in mutant lenses is involved in the proteolysis of crystallins and the progression of cataract formation.     

Sustaining excessive nitric oxide upregulates protein expression of nitric oxide synthase via soluble guanylyl cyclase: an in vivo study in rats

The aim of this study was to elucidate whether upregulation of the endothelial NO synthase (eNOS)/nitric oxide (NO) pathway is associated with downregulation of the NO/soluble guanylyl cyclase (sGC) pathway. To produce acutely or chronically excessive NO, lipopolysaccharide (LPS) was administered intraperitoneally to rats in a single dose of 4 mg/kg (LPS-single group) or in stepwise doses of 0.5, 1.0, and 2.0 mg/kg every other day (LPS-repeated group). At 24 hours after the treatment, in the thoracic aorta from the LPS-single group, both relaxations in response to sodium nitroprus-side (SNP), an NO donor, and acetylcholine (ACh) and protein levels of sGC and eNOS remained unchanged. In contrast, in the LPS-repeated group, the SNP-induced relaxation and sGC protein expression significantly decreased, while the ACh-induced relaxation and eNOS protein expression significantly increased compared with the non-treated control. All these changes in the relaxations and protein levels were restored by treatment with NOX-100, an NO scavenger. Furthermore, similar alteration in vascular function observed in the LPS-repeated group occurred in rats receiving SNP via subcutaneous using osmotic pumps (0.4 mg/h). These results indicate that persistent excessive NO exposure induces upregulation of the eNOS/NO pathway in the endothelium together with downregulation of the NO/sGC pathway.     

Transport of trace elements in lenses of normal and hereditary cataract UPL rats

The multitracer technique was applied to the determination of the uptake of trace elements in the lenses of normal and hereditary cataract UPL rats to investigate the transport mechanisms of trace elements during cataract development. Be, Na, Sc, V, Cr, Mn, Fe, Co, Zn, As, Se, Rb, Sr, Y, Zr, Tc, Ru and Rh accumulate in normal and UPL cataract rat lenses. The rates of uptake of trace elements differ among species and also differ between normal and UPL rat lenses. The uptakes of V and Sr are greater in normal rat lenses, while the uptakes of Mn and Co are greater in UPL rat lenses. High concentrations of Zn are transported into normal rat lenses in comparison with other elements. However, the uptake of Se was highest in the lenses of UPL cataract rats. In addition, the difference in Se uptake between the normal and UPL rat lenses was greatest among the tested trace elements. The present study suggests that the transport characteristics of trace elements are different in the lenses of normal and UPL cataract rats. The different transport characteristics of trace elements in the lenses of normal and UPL cataract rats, especially the higher accumulation of Se in UPL rat lenses, may be implicated in cataract development.     

复方牛磺酸滴眼剂抗过敏作用研究

目的：观察复方牛磺酸滴眼剂（ＣＴＵ）抗过敏作用。方法：以卵清蛋白致敏大鼠，两周后用卵清蛋白液滴眼引起眼过敏反应，同时静脉注射偶氮蓝（ＥＢ）染料，给予药物治疗。测定ＥＢ在眼的渗出量以评价眼组织微血管通透性和炎症水平。结果：ＣＴＵ治疗眼ＥＢ渗出量低于生理盐水治疗眼（Ｐ＜０．０１），与可的松治疗眼差异性无显著意义，渗出抑制率为４０．９６％。结论：复方牛磺酸滴眼剂可望开发成一临床治疗眼部过敏的药物     

人工泪液治疗白内障术后干眼症的效果分析

目的：评价人工泪液治疗白内障术后干眼症的临床效果。方法选择2011年5月~2013年5月于本院就诊的350例白内障术后干眼症患者,随机分为试验组和对照组各175例,两组患者均采用超声乳化白内障吸除术治疗白内障,术后对照组给予常规治疗,试验组在常规治疗的基础上加用人工泪液,记录两组治疗前后的泪液分泌检查（SIT）、角膜荧光素染色检查（FL）、泪膜破裂时间检查（BUT）水平及临床疗效,观察用药期间患者的不良反应情况。结果治疗前两组患者的SIT、FL、BUT水平差异无统计学意义（P〉0.05）,治疗后SIT、FL、BUT水平均显著改善,与治疗前比较,差异有统计学意义（P〈0.05）,且治疗后试验组的SIT、FL、BUT改善水平均优于对照组,差异有统计学意义（P〈0.05）;试验组的总有效率（93.1%）显著高于对照组（79.4%）,差异有统计学意义（χ2=13.9073,P=0.0002）;两组患者用药期间未发现明显不良反应情况。结论人工泪液治疗白内障术后干眼症,效果显著,适合临床推广应用。     

Comparison of the mechanisms of cataract development involving differences in Ca2+ regulation in lenses among three hereditary cataract model rats

We previously found that the increases in Ca2+ content in the lenses of three hereditary cataract model rats, UPL rat (UPLR), Shumiya cataract rat (SCR) and Ihara cataract rat (ICR), are inhibited by aminoguanidine, a selective inhibitor of inducible nitric oxide synthase, and that the mechanisms of Ca2+ enhancement in these rat models differ. In this study, we compare the mechanisms for dysfunction in Ca2+ regulation in UPLR, SCR and ICR. Decreases in the activity of Ca2+-ATPase were found in the lenses of SCR and ICR concurrent with cataract development. In contrast, the Ca2+-ATPase activity in UPLR with opaque lenses was higher than in those with transparent lenses. On the other hand, ATP levels were markedly decreased in UPLR with opaque lenses. The expression of cytochrome c oxidase (CCO)-1 mRNA and CCO activity in UPLR lenses was found to decrease during cataract development. The nitric oxide (NO) and lipid peroxide levels were also increased in the lenses of UPLR, SCR and ICR with opaque lenses. In UPLR, excessive NO may cause damage to the mitochondrial genome, resulting in a decrease in ATP production and increase in Ca2+-ATPase activity. The decrease in ATP content may cause the decrease in Ca2+-ATPase function resulting in the elevation in lens Ca2+. In SCR and ICR, excessive NO may cause an enhancement of lipid peroxidation resulting in the oxidative inhibition of Ca2+-ATPase. The decrease in Ca2+-ATPase activity may cause the elevation in the level of lens Ca2+, thus leading to lens opacification. Our findings show that the Ca2+ contents in the cataractous lenses of all three model rats are increased, the mechanisms for this Ca2+ enhancement is different in each rat model.     

Effect of black tea on lipid peroxide and glutathione levels in female rats

The effects of black tea (Camellia sinensis L.) on lipid peroxidation and glutathione (GSH) levels in carbon tetrachloride (CCl4)-treated female Wistar rats were examined. Two control groups and one treatment group were tested. The control groups were fed with a standard diet, while the black tea group was fed the standard diet plus 6% by weight dried black tea leaves. At the end of 2 months, a single dose of CCl4 (1 ml/kg, i.p.) in olive oil was administered to rats in one of the control groups and the black tea group. They were sacrificed after 2 hours. Rats in the other control group were administered olive oil in a similar fashion. Measurements were made of lipid peroxide levels in liver and plasma, glutathione levels in liver, and alanine transaminase (ALT) and aspartate transaminase (AST) activities in plasma. Liver lipid peroxide levels, plasma ALT and AST activities were significantly decreased in the black tea group compared with the CCl4-treated control group, while plasma lipid peroxide levels were not. These results are parallel to those previously found with Wistar male rats. Glutathione levels, however, were not significantly affected, in contrast to the data relating to male rats, either after CCl4 or black tea treatments. The results of our study add to the findings that black tea attenuates CCl4-induced hepatic injury but also indicates the susceptibility of glutathione levels to endocrinological effects.     

挤压伤后丙二醛和一氧化氮的变化

目的 观察挤压伤后脂质过氧化物的终产物－丙二醛（MDA）和一氧化氮（NO）含量变化。方法 复制挤压伤的大鼠模型，测定正常和挤压伤后平均动脉压（MAP）和血浆MDA、NO的含量变化，检测解压2h后心、肝、肾、小肠组织的MDA和NO含量。结果 解压后挤压伤组MAP值均低于对照组，血浆和组织中MDA、NO均高于对照组，并有统计学意义。结论 挤压伤后组织器官损伤与缺血再灌注有关，氧自由基和一氧化氮产生增多是其重要的机制。     

Altered L-arginine/nitric oxide synthase/nitric oxide pathway in the vascular adventitia of rats with sepsis

1. In recent studies, the vascular adventitia has been established as an important source of inducible nitric oxide synthase (iNOS) and subsequent nitric oxide (NO) production, even more powerful than the media in response to certain inflammatory factors, such as lipopolysaccharide (LPS). The adventitia has an independent L-arginine (L-Arg)/NOS/NO pathway and is involved in the regulation of vascular function. In the present study, we explored the changes in and the pathophysiological significance of the L-Arg/NOS/NO pathway in the adventitia of rats with sepsis. 2. Sepsis was induced by caecal ligation and puncture in order to observe changes in L-Arg transport, NOS gene expression and activity and NO generation in the vascular adventitia to determine the mechanism of activation of the L-Arg/NOS/NO pathway. 3. Severe sepsis resulted in severe disturbance of haemodynamic features, with decreased mean arterial blood pressure, brachycardia and inhibited cardiac function (decreased left ventricular +/-dP/dt(max)). Left ventricular end-diastolic pressure was elevated threefold (P < 0.01) under anaesthesia. Rats with sepsis showed severe glucopenia and lacticaemia. Plasma levels of the inflammatory factors macrophage chemoattractant protein-1 and interleukin-8 were increased five- and 29-fold, respectively (P < 0.01). 4. In the adventitia of the thoracic and abdominal aortas, the L-Arg/NO pathway was similarly characterized: the uptake of [(3)H]-L-Arg was Na(+) independent, with the peak occurring at approximately 40 min incubation. Total NOS activity was largely calcium independent (> 90%). The V(max) of L-Arg transport in the sepsis group was increased by 83.5% (P < 0.01), but the K(m) value was not significantly different compared with controls. 5. The mRNA levels of cationic amino acid transporter (CAT)-1 and CAT-2B in the sepsis group were increased by 86 and 62%, respectively (both P < 0.01). Inducible NOS activity was increased 2.8-fold compared with controls (P < 0.01) and iNOS mRNA levels were elevated approximately sixfold (P < 0.01). The NO levels in the plasma and incubation media (incubation for 40 min) in the sepsis group were increased by 144 and 273%, respectively (both P < 0.01). 6. The Arg/NOS/NO pathway was activated in the vascular adventitia of rats with sepsis shock. The L-Arg/NOS/NO pathway in the aortic adventitia may play an important role in the pathogenesis of sepsis and septic shock.     

桑银降糖胶囊对实验性糖尿病大鼠脂质过氧化物酶水平的影响

目的 观察桑银降糖胶囊对实验性糖尿病大鼠脂质过氧化物酶水平的影响.方法 用微量血糖测定法测定链脲霉素(STZ)实验性糖尿病大鼠实验前后各组空腹血糖浓度.用放免法测定血清胰岛素和C肽.用黄嘌呤-鲁米诺化学发光法测定血液超氧化物歧化酶(SOD)的活性.用硫化巴比妥酸(TBA)比色法测定血清丙二醛(MDA)的含量.用HE染色方法 观察桑银降糖胶囊治疗前后胰腺、肝脏、肾脏的组织学变化.结果 桑银降糖胶囊可升高糖尿病动物模型SD大鼠胰岛素(36.08±11.40 μIU/ml)和C肽(0.10±0.04 μIU/ml)的浓度,具有明显降糖(6.33±1.66)mmol/L作用,对糖尿病动物模型SD大鼠具有提高血液SOD的活性(591.00±53.03 ug/g.HB),降低MDA水平的功效(6.3±0.85umol/L.对糖尿病动物模型SD大鼠的胰腺、肝脏、肾脏等组织有改善作用.结论 桑银降糖胶囊减少自由基对糖尿病动物模型SD大鼠的胰腺、肝脏、肾脏等组织的损伤并具有保护作用,纠正糖尿病动物模型SD大鼠的糖代谢紊乱,减少并发症的发生.     

Effect of cyclooxygenase and nitric oxide synthase inhibitors on streptozotocin-induced hyperalgesia in rats

We examined a possible involvement of cyclooxygenase (COX) and nitric oxide synthase (NOS) products in hyperalgesia occurring during streptozotocin (STZ)-induced diabetes. Indomethacin and celecoxib were used as relatively selective inhibitors of COX-1 and COX-2, respectively. NOS inhibitors included: non-specific inhibitor N(G)-nitro-L-arginine and L-N(6)-(1-iminoethyl)lysine preferentially acting on inducible NOS (iNOS) as well as 7-nitroindazole relatively specific inhibitor neuronal NOS (nNOS). The above-mentioned agents, except 7-nitroindazole, suppressed hyperalgesia occurring after administration of STZ. The results of the study suggest participation of COX-1, COX-2 and iNOS, but not nNOS, in transmission of pain stimuli in STZ-induced diabetic hyperalgesia.     

Effect of prolonged nitric oxide synthesis inhibition on plasma fibrinogen concentration in rats

We examined whether nitro-L-arginine-methyl ester (L-NAME) causes a sustained elevation in plasma fibrinogen concentration in rats. Oral dosing of L-NAME (100 mg/kg per day) for 7 days significantly raised plasma fibrinogen concentration in rats. The increase in plasma fibrinogen, however, returned to control levels by the treatment for more than 7 days, in spite of progressive hypertension. Candesartan failed to reverse the transient hyperfibrinogenemia, indicating that the rise in plasma fibrinogen may occur through the mechanisms other than angiotensin II receptor activation. These data suggest that a prolonged L-NAME treatment does not cause chronic hyperfibrinogenemia in rats.