calpain and Hyperglycemia

Topics: Adult; Alleles; Blood Glucose; Calpain; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Gene Expression; Gene Frequency; Genotype; Glutathione Transferase; Glycated Hemoglobin; Humans; Hyperglycemia; INDEL Mutation; Insulin Resistance; Male; Middle Aged; Polymorphism, Single Nucleotide

The relationship between diabetes and endothelial dysfunction remains unclear, particularly the association with pathological activation of calpain, an intracellular cysteine protease. Here, we used human induced pluripotent stem cells-derived endothelial cells (iPSC-ECs) to investigate the effects of diabetes on vascular health. Our results indicate that iPSC-ECs exposed to hyperglycemia had impaired autophagy, increased mitochondria fragmentation, and was associated with increased calpain activity. In addition, hyperglycemic iPSC-ECs had increased susceptibility to cell death when subjected to a secondary insult-simulated ischemia-reperfusion injury (sIRI). Importantly, calpain inhibition restored autophagy and reduced mitochondrial fragmentation, concurrent with maintenance of ATP production, normalized reactive oxygen species levels and reduced susceptibility to sIRI. Using a human iPSC model of diabetic endotheliopathy, we demonstrated that restoration of autophagy and prevention of mitochondrial fragmentation via calpain inhibition improves vascular integrity. Our human iPSC-EC model thus represents a valuable platform to explore biological mechanisms and new treatments for diabetes-induced endothelial dysfunction.

Topics: Autophagy; Calpain; Cells, Cultured; Diabetes Complications; Diabetes Mellitus; Endothelial Cells; Endothelium, Vascular; Glycoproteins; Humans; Hyperglycemia; Induced Pluripotent Stem Cells; Mitochondria; Reactive Oxygen Species; Vascular Diseases

Vascular endothelial cells act as a selective barrier between circulating blood and vessel wall and play an important role in the occurrence and development of cardiovascular diseases. Astragaloside IV (As-IV) has a protective effect on vascular endothelial cells, but its underlying mechanism remains unclear. This study is aimed at investigating the effect of As-IV on endothelial dysfunction (ED).. Male Sprague-Dawley (SD) were injected intraperitoneally with 65 mg/kg streptozotocin (STZ) to induce diabetes and then administered orally with As-IV (40, 80 mg/kg) for 8 weeks. Vascular function was evaluated by vascular reactivity in vivo and in vitro. The expression of calpain-1 and eNOS in the aorta of diabetic rats was examined by western blot. NO production was measured using nitrate reductase method. Oxidative stress was determined by measuring SOD, GSH-px and ROS.. Our results showed that As-IV administration significantly improved diabetes associated ED in vivo, and both NAC (an antioxidant) and MDL-28170 (calpain-1 inhibitor) significantly attenuated hyperglycemia-induced ED in vitro. Meanwhile, pretreatment with the inhibitor l-NAME nearly abolished vasodilation to ACh in all groups of rats. Furthermore, As-IV increased NO production and the expression of eNOS in the thoracic aorta of diabetic rats. In addition, the levels of ROS were significantly increased, and the activity of SOD and GSH-px were decreased in diabetic rats, while As-IV administration reversed this change in a concentration-dependent manner.. These results suggest that As-IV improves endothelial dysfunction in thoracic aortas from diabetic rats by reducing oxidative stress and calpain-1.

Topics: Acetylcysteine; Animals; Aorta, Thoracic; Biomarkers; Calpain; Cysteine Proteinase Inhibitors; Diabetes Mellitus, Experimental; Dipeptides; Endothelium, Vascular; Human Umbilical Vein Endothelial Cells; Humans; Hyperglycemia; Male; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Rats; Rats, Sprague-Dawley; Saponins; Streptozocin; Triterpenes; Vasodilation

Many cellular and molecular studies in experimental animals and early retinal function tests in patients with diabetic retinopathy (DR) have shown that retinal neurodegeneration is an early event in the pathogenesis of the disease. Somatostatin (SST) is one of the most important neuroprotective factors synthesized by the retina: SST levels are decreased in parallel to retinal neurodegeneration in early stages of DR. In this study, we characterized the induction of apoptosis (programmed cell death) in a 661W photoreceptor-like cell line cultured under high glucose (HG) conditions and the effect of SST.. A 661W photoreceptor-like cell line and retinal explants from 10-week-old male C57BL/6 mice were cultured under HG conditions and treated with SST.. Hyperglycemia significantly reduced the cellular viability by increasing the percentage of apoptotic cells, and this effect was ameliorated by SST (p˂0.05). Activation of caspase-8 by hyperglycemia was found in the 661W cells and retinal explants and decreased in the presence of SST (p˂0.05). Moreover, we detected activation of calpain-2 associated with hyperglycemia-induced cell death, as well as increased protein tyrosine phosphatase 1B (PTP1B) protein levels; both had a pattern of cleavage that was absent in the presence of SST (p˂0.05). Treatment of the 661W cells and retinal explants with SST for 24 h increased the phosphorylation of type 1 insulin-like growth factor receptor (IGF-IR; tyrosine 1165/1166) and protein kinase B (Akt; serine 473), suggesting this survival signaling is activated in the neuroretina by SST (p˂0.05).. This study has provided new mechanistic insights first into the involvement of calpain-2 and PTP1B in the loss of cell survival and increased caspase-8-dependent apoptosis induced by hyperglycemia in photoreceptor cells and second, on the protective effect of SST against apoptosis by the enhancement of IGF-IR-mediated Akt phosphorylation.

Topics: Animals; Apoptosis; Calpain; Caspase 8; Cell Line; Cell Survival; Cytoprotection; Enzyme Activation; Glucose; Hyperglycemia; Male; Mice, Inbred C57BL; Phosphorylation; Photoreceptor Cells; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Proto-Oncogene Proteins c-akt; Receptor, IGF Type 1; Somatostatin

Plasma homocysteine (Hcy) levels are positively correlated with cardiovascular mortality in diabetes. However, the joint effect of hyperhomocysteinemia (HHcy) and hyperglycemia (HG) on endothelial dysfunction (ED) and the underlying mechanisms have not been studied. Mild (22 µmol/L) and moderate (88 µmol/L) HHcy were induced in cystathionine β-synthase wild-type (Cbs(+/+)) and heterozygous-deficient (Cbs(-/+)) mice by a high-methionine (HM) diet. HG was induced by consecutive injection of streptozotocin. We found that HG worsened HHcy and elevated Hcy levels to 53 and 173 µmol/L in Cbs(+/+) and Cbs(-/+) mice fed an HM diet, respectively. Both mild and moderate HHcy aggravated HG-impaired endothelium-dependent vascular relaxation to acetylcholine, which was completely abolished by endothelial nitric oxide synthase (eNOS) inhibitor N(G)-nitro-L-arginine methyl ester. HHcy potentiated HG-induced calpain activation in aortic endothelial cells isolated from Cbs mice. Calpain inhibitors rescued HHcy- and HHcy/HG-induced ED in vivo and ex vivo. Moderate HHcy- and HG-induced μ-calpain activation was potentiated by a combination of HHcy and HG in the mouse aorta. μ-Calpain small interfering RNA (μ-calpsiRNA) prevented HHcy/HG-induced ED in the mouse aorta and calpain activation in human aortic endothelial cells (HAECs) treated with DL-Hcy (500 µmol/L) and d-glucose (25 mmol) for 48 h. In addition, HHcy accelerated HG-induced superoxide production as determined by dihydroethidium and 3-nitrotyrosin staining and urinary 8-isoprostane/creatinine assay. Antioxidants rescued HHcy/HG-induced ED in mouse aortas and calpain activation in cultured HAECs. Finally, HHcy potentiated HG-suppressed nitric oxide production and eNOS activity in HAECs, which were prevented by calpain inhibitors or μ-calpsiRNA. HHcy aggravated HG-increased phosphorylation of eNOS at threonine 497/495 (eNOS-pThr497/495) in the mouse aorta and HAECs. HHcy/HG-induced eNOS-pThr497/495 was reversed by µ-calpsiRNA and adenoviral transduced dominant negative protein kinase C (PKC)β2 in HAECs. HHcy and HG induced ED, which was potentiated by the combination of HHcy and HG via μ-calpain/PKCβ2 activation-induced eNOS-pThr497/495 and eNOS inactivation.

Topics: Animals; Blood Glucose; Calpain; Cells, Cultured; Cystathionine beta-Synthase; Endothelial Cells; Humans; Hyperglycemia; Hyperhomocysteinemia; Male; Mice; Mice, Mutant Strains; Nitric Oxide Synthase Type III; Superoxides

Topics: Animals; Calpain; Endothelial Cells; Humans; Hyperglycemia; Hyperhomocysteinemia; Male

We showed that renal calpain 10, a mitochondrial and cytosolic Ca(2+)-regulated cysteine protease, is specifically decreased in kidneys of diabetic rats and mice, and is associated with diabetic nephropathy. The goals of this study were to examine renal calpain 10 and mitochondrial dysfunction in streptozotocin-induced hyperglycemic rats and determine the effects of siRNA-mediated knock down of renal calpain 10 on mitochondrial function. Four weeks after streptozotocin injection, calpain 10 protein and mRNA were decreased and calpain 10 substrates accumulated. We detected increased state 2 respiration in isolated renal mitochondria and increased markers of mitochondrial fission and mitophagy. All changes were prevented by daily insulin injection. Compared to scrambled siRNA, calpain 10 siRNA resulted in a marked decrease in renal calpain 10 at 2, 5 and 7 days. In concert with the loss of renal calpain 10, calpain 10 substrates accumulated, mitochondrial fusion decreased, mitochondrial fission and mitophagy increased. In summary, insulin-sensitive hyperglycemia induced loss of renal calpain 10 is correlated with renal mitochondrial dysfunction, fission and mitophagy, and specific depletion of renal calpain 10 produces similar mitochondrial defects. These results provide evidence that diabetes-induced renal mitochondrial dysfunction and renal injury may directly result from the loss of renal calpain 10.

Topics: Animals; Calpain; Chronic Disease; Down-Regulation; Gene Knockdown Techniques; Hyperglycemia; Insulin; Kidney; Male; Mitochondria; Rats; Rats, Sprague-Dawley; RNA, Messenger; RNA, Small Interfering; Streptozocin; Time Factors

We tested the hypothesis of a role for the calcium-dependent protease calpain in the endothelial dysfunction induced by hyperglycemic activation of protein kinase C (PKC).. Chronic hyperglycemia with insulin deficiency (type 1 diabetes) was induced in rats by streptozotocin. Total PKC and calpain activities, along with activity and expression level of the 2 endothelial-expressed calpains isoforms, μ- and m-calpain, were measured in vascular tissue homogenates by enzymatic assays and Western blot analysis, respectively. Intravital microscopy was used to measure and correlate leukocyte-endothelium interactions with calpain activity in the microcirculation. Expression levels and endothelial localization of the inflammatory adhesion molecule intercellular adhesion molecule-1 were studied by Western blot analysis and immunofluorescence, respectively. The mechanistic role of hyperglycemia alone in the process of PKC-induced calpain activation and actions was also investigated. We found that in the type 1 diabetic vasculature, PKC selectively upregulates the activity of the μ-calpain isoform. Mechanistic studies confirmed a role for hyperglycemia and PKCβ in this process. The functional implications of PKC-induced calpain activation were upregulation of endothelial expressed intercellular adhesion molecule-1 and leukocyte-endothelium interactions.. Our results uncover the role of μ-calpain in the endothelial dysfunction of PKC. Calpain may represent a novel molecular target for the treatment of PKC-associated diabetic vascular disease.

Topics: Animals; Calpain; Cell Communication; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Disease Models, Animal; Endothelium, Vascular; Hyperglycemia; Intercellular Adhesion Molecule-1; Leukocytes; Male; Mesenteric Arteries; Microcirculation; Protein Kinase C; Rats; Rats, Sprague-Dawley; Signal Transduction; Streptozocin; Up-Regulation

Recently we have shown that calpain-1 activation contributes to cardiomyocyte apoptosis induced by hyperglycemia. This study was undertaken to investigate whether targeted disruption of calpain would reduce myocardial hypertrophy and fibrosis in mouse models of type 1 diabetes.. Diabetes in mice was induced by injection of streptozotocin (STZ), and OVE26 mice were also used as a type 1 diabetic model. The function of calpain was genetically manipulated by cardiomyocyte-specific knockout Capn4 in mice and the use of calpastatin transgenic mice. Myocardial hypertrophy and fibrosis were investigated 2 and 5 months after STZ injection or in OVE26 diabetic mice at the age of 5 months. Cultured isolated adult mouse cardiac fibroblast cells were also investigated under high glucose conditions.. Calpain activity, cardiomyocyte cross-sectional areas, and myocardial collagen deposition were significantly increased in both STZ-induced and OVE26 diabetic hearts, and these were accompanied by elevated expression of hypertrophic and fibrotic collagen genes. Deficiency of Capn4 or overexpression of calpastatin reduced myocardial hypertrophy and fibrosis in both diabetic models, leading to the improvement of myocardial function. These effects were associated with a normalization of the nuclear factor of activated T-cell nuclear factor-κB and matrix metalloproteinase (MMP) activities in diabetic hearts. In cultured cardiac fibroblasts, high glucose-induced proliferation and MMP activities were prevented by calpain inhibition.. Myocardial hypertrophy and fibrosis in diabetic mice are attenuated by reduction of calpain function. Thus targeted inhibition of calpain represents a potential novel therapeutic strategy for reversing diabetic cardiomyopathy.

Topics: Animals; Calcium-Binding Proteins; Calpain; Cardiomyopathy, Hypertrophic; Cell Proliferation; Cells, Cultured; Diabetes Mellitus, Type 1; Diabetic Cardiomyopathies; Disease Models, Animal; Fibrosis; Gene Expression Regulation; Heart; Hyperglycemia; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Molecular Targeted Therapy; Myocardium; Streptozocin

Cardiomyocyte apoptosis contributes to cardiac complications of diabetes. The aim of this study was to investigate the role of calpain in cardiomyocyte apoptosis induced by hyperglycaemia.. In cultured adult rat ventricular cardiomyocytes, high glucose (33 mM) increased calpain activity and induced apoptosis, concomitant with the impairment of Na+/K+ ATPase activity. These effects of high glucose on cardiomyocytes were abolished by various pharmacological calpain inhibitors, knockdown of calpain-1 but not calpain-2 using siRNA, or over-expression of calpastatin, a specific endogenous calpain inhibitor. The effect of calpain inhibition on cardiomyocyte apoptosis was abrogated by ouabain, a selective inhibitor of Na+/K+ ATPase. Furthermore, blocking gp91(phox)-NADPH oxidase activation, L-type calcium channels, or ryanodine receptors prevented calpain activation and apoptosis in high glucose-stimulated cardiomyocytes. In a mouse model of streptozotocin-induced diabetes, administration of different calpain inhibitors blocked calpain activation, increased the Na+/K+ ATPase activity, and decreased apoptosis in the heart.. Calpain-1 activation induces apoptosis through down-regulation of the Na+/K+ ATPase activity in high glucose-stimulated cardiomyocytes and in vivo hyperglycaemic hearts. High glucose-induced calpain-1 activation is mediated through the NADPH oxidase-dependent pathway and associated with activation of L-type calcium channels and ryanodine receptors. Our data suggest that calpain activation may be important in the development of diabetic cardiomyopathy and thus may represent a potential therapeutic target for diabetic heart diseases.

Topics: Animals; Apoptosis; Calcium; Calcium Channels; Calcium-Binding Proteins; Calpain; Caspase 3; Enzyme Activation; Hyperglycemia; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Myocytes, Cardiac; NADPH Oxidase 2; NADPH Oxidases; Sodium-Potassium-Exchanging ATPase

Recent studies have reported that the calcium-dependent protease calpain is involved in hyperglycaemia-induced endothelial dysfunction and that the Na(+)/H(+) exchanger (NHE) is responsible for an increase in the intracellular calcium (Ca(2+)(i)) concentration in diabetes. We hypothesized that activation of NHE mediates hyperglycaemia-induced endothelial dysfunction via calcium-dependent calpain.. Exposure of human umbilical vein endothelial cells (HUVECs) to high glucose (HG, 30 mM d-glucose) time dependently increased both the Ca(2+)(i) concentration and calpain activity. Chelation of free Ca(2+)(i) with 1,2-bis (2-aminophenoxy) ethane-N, N, N',N'-tetraacetic acid abolished the HG-increased calpain activity. In addition, HG activated NHE in a time-dependent manner, but cariporide, an NHE inhibitor, blocked the HG-induced increase in NHE activity. Furthermore, cariporide or NHE siRNA (small interfering ribonucleic acid) attenuated the HG-induced increases of both Ca(2+)(i) concentration and calpain activity. All of these HG-induced effects in HUVECs, including decreased endothelial nitric oxide synthase (eNOS) activity and NO (nitric oxide) production and increased dissociation of heat shock protein (hsp90) from eNOS, were NHE or calpain reversible. In vivo experiments showed that cariporide treatment via inhibition of NHE activity significantly attenuated the hyperglycaemia-induced impairment of acetylcholine-induced endothelium-dependent relaxation in streptozotocin-injected diabetic rats.. Activation of NHE via calcium-dependent calpain contributes to hyperglycaemia-induced endothelial dysfunction through dissociation of hsp90 from eNOS.

Topics: Animals; Calcium; Calpain; Cells, Cultured; Chelating Agents; Cysteine Proteinase Inhibitors; Diabetes Mellitus, Experimental; Dose-Response Relationship, Drug; Endothelium, Vascular; Glucose; Guanidines; HSP90 Heat-Shock Proteins; Humans; Hyperglycemia; Male; Nitric Oxide; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Rats; Rats, Sprague-Dawley; RNA Interference; RNA, Small Interfering; Sodium-Hydrogen Exchangers; Sulfones; Time Factors; Vasodilation; Vasodilator Agents

Increased permeability to albumin is a well-known feature of diabetic microvasculature and a negative prognostic factor of vascular complications. The mechanisms responsible for loss of the physiological albumin barrier in diabetic organs remain only partially understood. We have recently demonstrated that the protease mu-calpain is activated in hyperglycemia, which causes endothelial dysfunction and vascular inflammation. In the present study, we investigated whether mu-calpain is involved in the hyperpermeability of the diabetic vasculature. We also investigated the mechanistic roles of hyperglycemia and leukocyte adhesion in this process. Albumin permeability in the intact microcirculation of the Zucker diabetic fatty (ZDF) rat was quantified by intravital microscopy. Extravasation of albumin in the microcirculation of ZDF rats was significantly increased when compared with nondiabetic Zucker lean (ZL) rats. Microvascular albumin leakage was prevented by either antisense depletion of mu-calpain or pharmacological inhibition of calpain in vivo. Calpain inhibition also attenuated urinary albumin excretion in ZDF rats. Glucose concentrations in the range of those found in the blood of ZDF rats increased albumin permeability in nondiabetic ZL rats. Thus, this demonstrates a mechanistic role for hyperglycemia in the hypermeability of diabetes. Depletion of polymorphonuclear leukocytes in vivo failed to prevent glucose-induced hypermeability, which suggests that hyperglycemia can disrupt the physiological endothelial cell barrier of the microcirculation, even in the absence of increased overt leukocyte-endothelium interactions.

Topics: Albumins; Animals; Calpain; Capillary Permeability; Diabetes Mellitus, Type 2; Dipeptides; Disease Models, Animal; Endothelium, Vascular; Enzyme Inhibitors; Hyperglycemia; Leukocytes; Male; Microcirculation; Oligodeoxyribonucleotides, Antisense; Rats; Rats, Zucker; Vascular Diseases

To detect the association among calpain-10(CAPN-10) gene polymorphism, hypentension and hyperglycemia.. 378 individuals in the present study were the second generation offsprings of 187 hypentensives and 19 1 nonhypertensives. Fasting plasma glucose (FPG), insulin, triglyceride and fibrinogen were determined. The polymorphism of UCSNP-43 and UCSNP-44 of CAPN 10 gene were analysed with PCR-SSCP method.. (1)The frequency of G/G geno type of UCSNP-43 was higher in the second generation offsprings of the hypertensives than that in the nonhypertensive controls(86.6%, 75.4%, P < 0.05). (2) The frequenncy of G/G genotype of UCSNP-43 was higher in the hypertensive parents of the second generation offsprings in the hypertensive groups than that in the normotensive parent of the second generation offsprings of the nonhypertensive control groups (OR = 2.84, P = 0.01). After adjustment of age, sex and body mass index (BMI), the frequency of G/G genotype in the highest FPG-quartiles (FPG 5.42 +/- 0.1mmol/L) was much more than that in the lowest FPG quartiles (FPG 4.09 +/- 0.3 mmol/L) with OR of 3.32.. Polymorphism of UCSNP-43 in CAPN-10 gene might be one of the genetic factors contributing to hypertension and diabetes mellitus in the population in Daqing city. It may be a predictor of type 2 diabetes mellitus (T2DM) in the decendents of hypertensives.

Topics: Adult; Age Factors; Blood Glucose; Calpain; Female; Fibrinogen; Gene Frequency; Genetic Diseases, Inborn; Humans; Hyperglycemia; Hypertension; Insulin; Male; Polymorphism, Genetic; Sex Factors; Triglycerides

To examine the role of calcium-dependent and -independent proteolytic activity in the globulization of isolated fiber cells and glucose-induced lens opacification.. Fiber cells from rat lens cortex were isolated, and the [Ca(2+)](i) and protease activity in the isolated fibers were determined by using a calcium binding dye and the protease substrate t-butoxycarbonyl-Leu-Met-7-amino-4-chloromethylcoumarin (BOC-Leu-Met-CMAC). The activity of calpain in the lens cortex homogenate was determined with fluorescein-casein in the presence of Ca(2+) and that of fiber cell globulizing aminopeptidase (FCGAP) with BOC-Leu-Met-CMAC and reduced glutathione (GSH) in the absence of Ca(2+). The lens proteases-calpain and the novel aminopeptidase FCGAP were partially purified by diethylaminoethyl (DEAE) gel column chromatography. Single fiber cells were isolated from rat lens, plated on coverslips, and placed in a temperature-controlled chamber. Their globulization time was determined by the appearance of light-scattering globules in the absence and the presence of protease inhibitors including the aminopeptidase inhibitor bestatin. To investigate the effect of the protease inhibitors E-64 and bestatin on the prevention of hyperglycemic cataract, the rat lenses were cultured in medium 199 in the presence of 5.5 and 50 mM glucose and in the absence and the presence of protease inhibitors. Changes in light transmission by the lenses were determined by digital image analysis.. Normal levels of lens fiber cell [Ca(2+)](i), determined by using a cell-permeable dye were approximately 100 nM, and the protease activity determined with BOC-Leu-Met-CMAC was maximum at [Ca(2+)](i) of approximately 500 nM. A large fraction of the FCGAP that cleaves BOC-Leu-Met-CMAC was separated from calpain, which cleaves fluorescein-casein, by diethylaminoethyl (DEAE) gel column chromatography. The FCGAP did not bind to the column, whereas calpain bound to the column and was eluted by approximately 180 mM NaCl. Unlike calpain, the FCGAP did not require calcium for activation and did not cleave fluorescein-casein. However, the Ca(2+)-dependent calpain activated FCGAP, indicating that the latter may exist in pro-protease form. The FCGAP was selectively inhibited by the specific aminopeptidase inhibitor bestatin, indicating that FCGAP could be an aminopeptidase. However, the FCGAP was found to be immunologically distinct from leucine aminopeptidase and calpain. Perfusion of the isolated rat lens fiber cells with Ringer's solution led to their globulization in 30 +/- 3 minutes. Addition of 0.5 mM of the protease inhibitors E-64 and leupeptin increased the globulization time to 60 and 100 minutes, respectively, whereas no globulization of the fiber cells was observed for 4 hours in the presence of 0.05 mM bestatin. In rat lens cultured in medium containing 50 mM glucose, both E-64 and bestatin (0.05 mM each) significantly reduced the extent of opacification, indicating that an aminopeptidase, downstream to a Ca(2+)-dependent protease, may be involved in mediating cataractogenic changes.. In addition to calpain, a Ca(2+)-independent novel protease, FCGAP, a novel aminopeptidase, represents a significant fraction of the total proteolytic activity in the lens. Inhibition of FCGAP by bestatin attenuates Ca(2+)-induced globulization of the isolated fiber cells in vitro and hyperglycemia-induced opacification of cultured rat lens.

Topics: Aminopeptidases; Animals; Calcium; Calpain; Cataract; Chromatography, Ion Exchange; Glucose; Glutathione; Hyperglycemia; Lens Cortex, Crystalline; Leucine; Organ Culture Techniques; Phthalimides; Protease Inhibitors; Rats; Rats, Sprague-Dawley