Mitochondrial metabolism is crucial for providing energy and heme precursors during erythroid development. Oxoglutarate dehydrogenase complex (OGDC) is a key enzyme in the mitochondrial tricarboxylic acid (TCA) cycle, and its level gradually increases during erythroid development, indicating its significant role in erythroid development. The aim of the present study was to explore the role and mechanism of OGDC in erythroid development. In this study, we treated erythroid progenitor cells with CPI-613, a novel lipoic acid analog that competitively inhibits OGDC. The results showed that CPI-613 inhibited erythropoietin (EPO)-induced differentiation and enucleation of human CD34⁺ hematopoietic stem cells into erythroid cells, suppressed cell proliferation, and induced apoptosis. The results of in vivo experiments showed that CPI-613 also hindered the recovery of mice from acute hemolytic anemia. Further mechanism research results showed that CPI-613 increased reactive oxygen species (ROS) in erythroid progenitor cells, inhibited mitochondrial respiration, caused mitochondrial damage, and suppressed heme synthesis, thereby inhibiting erythroid differentiation. Clinical research results showed that oxoglutarate dehydrogenase (OGDH) protein expression levels were up-regulated in bone marrow cells of polycythemia vera (PV) patients. Treatment with CPI-613 significantly inhibited the excessive proliferation and differentiation of erythroid progenitor cells of the PV patients. These findings demonstrates the critical role of OGDC in normal erythroid development, suggesting that inhibiting its activity could be a novel therapeutic strategy for treating PV.
Animals ; Humans ; Mitochondria/metabolism* ; Mice ; Ketoglutarate Dehydrogenase Complex/physiology* ; Cell Differentiation/drug effects* ; Cells, Cultured ; Erythropoiesis/drug effects* ; Reactive Oxygen Species/metabolism* ; Cell Proliferation/drug effects* ; Erythroid Precursor Cells/cytology* ; Apoptosis/drug effects* ; Thioctic Acid/pharmacology* ; Caprylates ; Sulfides

ObjectiveTo study the protective effect of lipoic acid (LA) on the spermatogenic function of the male rats with oligoasthenozoospermia induced by ornidazole (ORN).

METHODSSeventy male SD rats were equally randomized into groups A (solvent control: 1 ml 0.5% CMC-Na + 1 ml olive oil), B (low-dose ORN model: 400 mg/kg ORN suspension + 1 ml olive oil), C (low-dose ORN + low-dose LA treatment: 400 mg/kg ORN + 50 mg/kg LA), D (low-dose ORN + high-dose LA treatment: 400 mg/kg ORN + 100 mg/kg LA), E (high-dose ORN model: 800 mg/kg ORN suspension + 1 ml olive oil), F (high-dose ORN + low-dose LA treatment: 800 mg/kg ORN + 50 mg/kg LA), and G (high-dose ORN + high-dose LA treatment: 800 mg/kg ORN + 100 mg/kg LA), and treated respectively for 20 successive days. Then all the rats were sacrificed and the weights of the body, testis, epididymis and seminal vesicle obtained, followed by calculation of the organ index, determination of epididymal sperm concentration and motility, and observation of the histomorphological changes in the testis and epididymis by HE staining.

RESULTSCompared with group A, group E showed significantly decreased body weight (［117.67 ± 11.53］ vs ［88.11 ± 12.65］ g, P < 0.01) and indexes of the testis (［1.06 ± 0.12］ vs ［0.65 ± 0.13］ %, P < 0.01) and epididymis (［0.21 ± 0.03］ vs ［0.17 ± 0.01］ %, P < 0.01). In comparison with group E, group F exhibited remarkable increases in the epididymal index (［0.17 ± 0.01］ vs ［0.20 ± 0.02］ %, P < 0.01), and so did group G in the body weight (［88.11 ± 12.65］ vs ［102.70 ± 16.10］ g, P < 0.05) and the indexes of the testis (［0.65 ± 0.13］ vs ［0.95 ± 0.06］ %, P < 0.01) and epididymis (［0.17 ± 0.01］ vs ［0.19 ± 0.02］ %, P < 0.05), but no obvious difference was observed in the index of seminal vesicle among different groups. Compared with group A, group B manifested significant decreases in sperm motility (［74.12 ± 8.73］ vs ［40.25 ± 6.08］ %, P < 0.01), and so did group E in sperm count (［38.59 ± 6.40］ vs ［18.67 ± 4.59］ ×105/100 mg, P < 0.01) and sperm motility (［74.12 ± 8.73］ vs ［27.58 ± 8.43］ %, P < 0.01). Sperm motility was significantly lower in group B than in C and D (［40.25 ± 6.08］ vs ［58.13 ± 7.62］ and ［76.04 ± 8.44］%, P < 0.01), and so were sperm count and motility in group E than in F and G (［18.67 ± 4.59］ vs ［25.63 ± 9.66］ and ［29.92 ± 4.15］ ×105/100 mg, P < 0.05 and P < 0.01; ［27.58 ± 8.43］ vs ［36.56 ± 11.08］ and ［45.05 ± 9.59］ %, P < 0.05 and P < 0.01). There were no obvious changes in the histomorphology of the testis and epididymis in groups A, B, C and D. Compared with group A, group E showed necrotic and exfoliated spermatogenic cells with unclear layers and disorderly arrangement in the seminiferous tubules and remarkably reduced sperm count with lots of noncellular components in the epididymal cavity, while groups F and G exhibited increased sperm count in the seminiferous tubules and epididymis lumen, also with exfoliation, unclear layers and disorderly arrangement of spermatogenic cells, but significantly better than in group E.

CONCLUSIONSLA can reduce ORN-induced damage to the spermatogenetic function of rats, improve sperm quality, and protect the reproductive system.

Animals ; Antioxidants ; pharmacology ; Asthenozoospermia ; chemically induced ; drug therapy ; Body Weight ; drug effects ; Epididymis ; anatomy & histology ; drug effects ; Male ; Oligospermia ; chemically induced ; drug therapy ; Ornidazole ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Seminal Vesicles ; anatomy & histology ; drug effects ; Seminiferous Tubules ; anatomy & histology ; drug effects ; Sperm Count ; Sperm Motility ; drug effects ; Spermatogenesis ; drug effects ; Spermatozoa ; drug effects ; Testis ; anatomy & histology ; drug effects ; Thioctic Acid ; pharmacology

The epithelial cytokine response, associated with reactive oxygen species (ROS), is important in Helicobacter pylori (H. pylori)-induced inflammation. H. pylori induces the production of ROS, which may be involved in the activation of mitogen-activated protein kinases (MAPK), janus kinase/signal transducers and activators of transcription (Jak/Stat), and oxidant-sensitive transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB), and thus, expression of interleukin-8 (IL-8) in gastric epithelial cells. alpha-lipoic acid, a naturally occurring thiol compound, is a potential antioxidant. It shows beneficial effects in treatment of oxidant-associated diseases including diabetes. The present study is purposed to investigate whether alpha-lipoic acid inhibits expression of inflammatory cytokine IL-8 by suppressing activation of MAPK, Jak/Stat, and NF-kappaB in H. pylori-infected gastric epithelial cells. Gastric epithelial AGS cells were pretreated with or without alpha-lipoic acid for 2 h and infected with H. pylori in a Korean isolate (HP99) at a ratio of 300:1. IL-8 mRNA expression was analyzed by RT-PCR analysis. IL-8 levels in the medium were determined by enzyme-linked immunosorbent assay. NF-kappaB-DNA binding activity was determined by electrophoretic mobility shift assay. Phospho-specific and total forms of MAPK and Jak/Stat were assessed by Western blot analysis. ROS levels were determined using dichlorofluorescein fluorescence. As a result, H. pylori induced increases in ROS levels, mRNA, and protein levels of IL-8, as well as the activation of MAPK [extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase 1/2 (JNK1/2), p38], Jak/Stat (Jak1/2, Stat3), and NF-kappaB in AGS cells, which was inhibited by alpha-lipoic acid. In conclusion, alpha-lipoic acid may be beneficial for prevention and/or treatment of H. pylori infection-associated gastric inflammation.
Enzyme-Linked Immunosorbent Assay ; Epithelial Cells/metabolism ; Gastric Mucosa/*drug effects/metabolism/microbiology ; Gene Expression Regulation, Bacterial ; Helicobacter Infections/immunology/*metabolism ; Helicobacter pylori/drug effects/*pathogenicity ; Humans ; Interleukin-8/genetics/*metabolism ; JNK Mitogen-Activated Protein Kinases ; Janus Kinase 1 ; Mitogen-Activated Protein Kinases/*biosynthesis ; NF-kappa B/*metabolism ; RNA, Messenger/isolation & purification/metabolism ; Reactive Oxygen Species/metabolism ; STAT3 Transcription Factor ; Stomach/metabolism/*microbiology ; Thioctic Acid/*pharmacology

OBJECTIVETo investigate the role of oxidative stress in impaired intermediate-conductance Ca(2+)-activated potassium channels (IKCa)- and small-conductance Ca(2+)-activated potassium channels (SKCa)-mediated relaxation in diabetic resistance arteries.

METHODSRat diabetic model was induced by a high fat and high glucose diet and streptozotocin (STZ) injection. Endothelial function of mesenteric arteries was assessed with the use of wire myography. The expression levels of IKCa and SKCa in cultured human umbilical vein endothelial cells (HUVECs) treated with H2O2 and/or antioxidant alpha lipoic acid (ALA) were measured using Western blotting.

RESULTSIKCa- and SKCa-mediated vasodilatation in response to acetylcholine was impaired in the third-order mesenteric arterioles of diabetic rats. In cultured HUVECs, H2O2 significantly decreased the protein expression of IKCa and SKCa. ALA alleviated the impairment of both vasodilatation function of the mesenteric arterioles ex vivo and enhanced the expression of IKCa and SKCa challenged with H2O2 in cultured HUVECs.

CONCLUSIONOur data demonstrated for the first time that impaired IKCa- and SKCa-mediated vasodilatation in diabetes was induced, at least in part, by oxidative stress via down-regulation of IKCa and SKCa channels.

Animals ; Cells, Cultured ; Diabetes Mellitus, Experimental ; metabolism ; physiopathology ; Human Umbilical Vein Endothelial Cells ; drug effects ; pathology ; Humans ; Hydrogen Peroxide ; pharmacology ; Intermediate-Conductance Calcium-Activated Potassium Channels ; metabolism ; Male ; Mesenteric Arteries ; physiopathology ; Oxidative Stress ; Rats ; Rats, Sprague-Dawley ; Small-Conductance Calcium-Activated Potassium Channels ; metabolism ; Thioctic Acid ; pharmacology ; Vasodilation

OBJECTIVETo investigate the accumulation of advanced glycation end products (AGEs) and expression of receptor for AGEs (RAGE) in streptozocin (STZ)-induced diabetic nephropathy in rats, and the role of antioxidants on the AGEs-RAGE signaling.

METHODSDiabetic rats were induced by once intraperitoneal injection of STZ at the dose of 60 mg/kg, and randomly divided into the DN group (n=12, treated with normal saline by intraperitoneal injection, once daily), the extract of Ginkgo biloba (EGb) group (n=14, treated with EGb 300 mg/kg by oral administration, once every other day), and the alpha-lipoic acid (ALA) group (n=12, treated with ALA at the dose of 35 mg/kg by intraperitoneal injection, once every other day). Rats of the normal control group (n=10) were given vehicle citrate buffer at the dose of 60 mg/kg. Rats were sacrificed at the 12th week and the 20th week of this study. The four groups were compared in terms of body weight, blood glucose, renal function, 24-h urine protein. Renal pathological changes were observed by PAS staining. Oxidative stress indices were detected using spectrophotometry. The concentrations of AGEs were measured using fluoro spectrophotometry, and the expressions of RAGE were detected by Real-time PCR and Western blot.

RESULTSCompared with the normal control group, the 24-h urine protein quantitation was higher and the glomerular filtration rate increased in rats at the 12th week and the 20th week. The pathological tissue staining showed dilated glomerular mesangium, proliferated glomerular matrix, vacuolar degeneration of the renal tubular epithelium. Malonaldehyde (MDA) levels and 8-hydroxide radical guanine deoxyriboside (8-OHdG) levels increased, and catalase (CAT) and reduced glutathione hormone (GSH) levels decreased. The AGEs contents in serum and renal tissue homogenate increased. The expressions of RAGE mRNA and protein increased in the DN group at the 12th and the 20th week. The 24-h urine protein quantitation was reduced in the EGb group and the ALA group, with alleviated pathological changes, lowered MDA and 8-OHdG levels, increased CAT and GSH levels, decreased AGEs contents, and down-regulated RAGE expressions.

CONCLUSIONSAGEs contents increased and RAGE expression up-regulated in the circulation and local renal tissues in DN rats. EGb and ALA could inhibit AGEs production and down-regulate RAGE expressions by reducing oxidative stress, thus further improving the renal tissue structure and renal functions of DN rats. It had better application prospect in treatment and prevention of DN.

Animals ; Antioxidants ; pharmacology ; Diabetes Mellitus, Experimental ; metabolism ; Diabetic Nephropathies ; metabolism ; Ginkgo biloba ; Glycation End Products, Advanced ; metabolism ; Kidney ; metabolism ; Male ; Rats ; Rats, Wistar ; Receptor for Advanced Glycation End Products ; Receptors, Immunologic ; metabolism ; Thioctic Acid ; pharmacology

OBJECTIVETo explore arsenic-induced oxidative stress and the protective efficacy of α-lipoic acid and vitamin c.

METHODS50 male SD rats were randomly divided into 5 groups. Ten rats (the control group) were exposed to deionized water for 6 weeks, and the others were alone exposed to sodium arsenite (50 mg/L water) for 6 weeks, at the same time, three group rats were administered intragastrically (i.g.) with α-lipoic acid 10 mg×kg(-1)×d(-1) and vitamin C 25 mg×kg(-1)×d(-1) either alone or in combination. At the end of experiment, blood was drawn from abdominal aorta, and then the blood, brain and liver of rats were used for biochemical assays, including blood glutathione (GSH), δ-aminolevulinic acid dehydratase (δ-ALAD ), reactive oxygen species (ROS) and oxidized glutathione (GSSG) level. At the same time, the super oxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, catalase (CAT) activity, ATPase activity of brain and liver were determined. The caspase activity of brain were also determined.

RESULTSThere were a significant increase in ROS level (P < 0.05), but a significant decrease in δ-ALAD activity (P < 0.01) in the chronic arsenic toxicity model group compared with the control group. These alterations were marginally restored by co-administration of vitamin C and α-lipoic acid individually, while significant recovery was observed in the animals supplemented with both the antioxidants together with arsenite in rat (P < 0.05). At the same time, there was a significant increase in the ROS and TBARS level of the brain and liver (P < 0.05), and caspase activity of the brain (P < 0.05), while there was a significant decrease in antioxidant enzymes and ATPase activity on arsenite exposure in rats (P < 0.05). These alterations were also marginally restored by co-administration of vitamin C and α-lipoic acid individually, while significant recovery was observed in the animals supplemented with both the antioxidants together with arsenite in rat (P < 0.05).

CONCLUSIONSArsenite-induced oxidative stress can be significantly protected by co-administration of α-lipoic acid and vitamin C individually, but the best effects could be observed with combined administration of two antioxidants during arsenite exposure in animals. The dietary intervention of or supplementation with natural dietary nutrients is possible to prevent the effects of arsenic in populations of risk.

Animals ; Arsenic Poisoning ; metabolism ; Ascorbic Acid ; pharmacology ; Male ; Oxidative Stress ; drug effects ; Rats ; Rats, Sprague-Dawley ; Thioctic Acid ; pharmacology

OBJECTIVETo study the functional and ultramicrostructural effects of alpha lipoic acid on hypothalamus-pituitary-adrenal (HPA) axis in normal and diabetic rats.

METHODSUsing radioimmunoassay we observed the effects of three doses (1, 20, and 100 mg/kg) of alpha lipoic acid injected intraperitoneally for 3 weeks on the plasma levels of CRH, ACTH and COR in normal and diabetic rats. The ultramicrostructural changes of the hypophysis and pituitary gland after alpha lipoic acid treatment were observed under transmission electron microscope.

RESULTSCompared with the control group, CRH level in lipoicin-treated normal and diabetic rats was significantly reduced (P<0.05). ACTH level of the 3 lipoicin doses groups of normal rats decreased, and a significant reduction occurred in medium-dose lipoicin group of diabetic rats (P<0.05). COR level showed the same changes as CRH level in normal rats, but decreased significantly in high- and medium-dose lipoicin groups of diabetic rats. Lipoicin treatment produced no apparent effect on the ultramicrostructures of the hypophysis and pituitary gland cells, which were the targets of diabetic lesions with low metabolism functions. Lipoicin treatment obviously enhanced the hypophysis and pituitary gland cell metabolism function to resist diabetic oxidative stress.

CONCLUSIONLipoicin can inhibit the HPA axis directly or indirectly in normal and diabetic rats.

Animals ; Diabetes Mellitus, Experimental ; pathology ; physiopathology ; Hypothalamo-Hypophyseal System ; drug effects ; physiology ; ultrastructure ; Male ; Pituitary-Adrenal System ; diagnostic imaging ; drug effects ; physiology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Thioctic Acid ; pharmacology ; Ultrasonography

BACKGROUNDCardiac failure is a leading cause of the mortality of diabetic patients. In part this is due to a specific cardiomyopathy, referred to as diabetic cardiomyopathy. Oxidative stress is widely considered to be one of the major factors underlying the pathogenesis of the disease. This study aimed to test whether the antioxidant alpha-lipoic acid (alpha-LA) could attenuate mitochondrion-dependent myocardial apoptosis through suppression of mitochondrial oxidative stress to reduce diabetic cardiomyopathy.

METHODSA rat model of diabetes was induced by a single tail intravenous injection of streptozotocin (STZ) 45 mg/kg. Experimental animals were randomly assigned to 3 groups: normal control (NC), diabetes (DM) and DM treated with alpha-LA (alpha-LA). The latter group was administered with alpha-LA (100 mg/kg ip per day), the remainder received the same volume vehicle. At weeks 4, 8, and 12 after the onset of diabetes, cardiac apoptosis was examined by TUNEL assay. Cardiomyopathy was evaluated by assessment of cardiac structure and function. Oxidative damage was evaluated by the content of malondialdehyde (MDA), reduced glutathione (GSH) and the activity of manganese superoxide diamutase (Mn-SOD) in the myocardial mitochondria. Expression of caspase-9 and caspase-3 proteins was determined by immunohistochemistry and mitochondrial cytochrome c release was detected by Western blotting.

RESULTSAt 4, 8, and 12 weeks after the onset of diabetes, significant reductions in TUNEL-positive cells, caspase-9,-3 expression, and mitochondrial cytochrome c release were observed in the alpha-LA group compared to the DM group. In the DM group, the content of MDA in the myocardial mitochondria was significantly increased, and there was a decrease in both the mitochondrial GSH content and the activities of Mn-SOD. They were significantly improved by alpha-LA treatment. HE staining displayed structural abnormalities in diabetic hearts, while alpha-LA reversed this structural derangement. The index of cardiac function (+/-dp/dtmax) in the diabetes group was aggravated progressively from 4 weeks to 12 weeks, but alpha-LA delayed deterioration of cardiac function (P < 0.05).

CONCLUSIONSOur findings indicate that the antioxidant alpha-LA can effectively attenuate mitochondria-dependent cardiac apoptosis and exert a protective role against the development of diabetic cardiomyopathy. The ability of alpha-LA to suppress mitochondrial oxidative damage is concomitant with an enhancement of Mn-SOD activity and an increase in the GSH content of myocardial mitochondria.

Animals ; Apoptosis ; drug effects ; Cardiomyopathies ; drug therapy ; Caspase 3 ; analysis ; Caspase 9 ; analysis ; Glutathione ; metabolism ; Immunohistochemistry ; In Situ Nick-End Labeling ; Male ; Malondialdehyde ; metabolism ; Mitochondria, Heart ; drug effects ; metabolism ; Myocardium ; cytology ; Oxidative Stress ; drug effects ; Rats ; Rats, Wistar ; Superoxide Dismutase ; metabolism ; Thioctic Acid ; pharmacology ; therapeutic use

OBJECTIVETo investigate the mechanism of diabetic erectile dysfunction (ED) and find new methods for its treatment by detecting the changes in nitric oxide synthase (NOS) isoforms and erectile function of diabetic rats and observing the effects of insulin and alpha-lipoic acid (LA) on it.

METHODSFifty male Sprague-Dawley rats were divided into Groups A (normal control, n=10), B (non-intervention diabetes mellitus, n=13), C (insulin intervention diabetes mellitus, n=12), and D (insulin + LA intervention, n=15). And the diabetic models were made by intraperitoneal injection of streptozocin (STZ). Eight weeks later, the erectile function of the rats was assessed following apomorphine injection and the contents of NOS isoforms in the erectile tissues measured by immunohistochemical staining.

RESULTSAll the rats of Group A showed a normal erectile function (100%). In comparison, those in Groups B, C and D exhibited a significantly decreased rate, 28.6% in Group B, 62.5% in Group C and 80.9% in Group D. The numbers of positive nNOS fibers and eNOS in the penile tissues per visual field were 86.7 and 9.6 in Group A, but only 36.5 and 3.3 in Group B, 52.7 and 5.7 in Group C, and 71.4 and 7.4 in Group D (P < 0.05). However, the expression of iNOS was significantly lower in Group A (6.9) than in Groups B (43.6), C (36.2) and D (19.3) (P < 0.05). Compared with Groups B and C, the erectile function and the expressions of nNOS and eNOS were markedly increased, while the expression of iNOS significantly decreased in Group D (P < 0.05).

CONCLUSIONDiabetes mellitus severely affects penile erectile function and the expressions of NOS isoforms in the cavernous tissues, for which hyperglycemia is mainly responsible. LA is proved obviously efficacious for diabetic ED, which might be related to its antioxidant effect.

Animals ; Diabetes Mellitus, Experimental ; metabolism ; physiopathology ; Erectile Dysfunction ; metabolism ; physiopathology ; Insulin ; pharmacology ; Male ; Nitric Oxide Synthase ; metabolism ; Nitric Oxide Synthase Type I ; Nitric Oxide Synthase Type III ; metabolism ; Penile Erection ; Penis ; metabolism ; physiopathology ; Protein Isoforms ; Rats ; Rats, Sprague-Dawley ; Thioctic Acid ; pharmacology

OBJECTIVETo evaluate the effect of sustained-release alpha-lipoic acid tablets (SRLA) on blood lipid, glucose and insulin levels in hyperlipidemic New Zealand rabbits.

METHODSTwenty-four New Zealand rabbits were randomized into normal diet group, high-fat diet group, and high-fat diet + SRLA (300 mg/tablet) group with corresponding feed. At the beginning and 4 weeks after the feeding, the serum levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), blood glucose, and serum insulin were measured, and insulin sensitivity index (ISI) was calculated.

RESULTSFour weeks after feeding with high-fat diet, the insulin levels was elevated and the ISI lowered in the New Zealand rabbits, indicating successful establishment of the animal model of hyperlipidemia. Compared with the high-fat diet group, the serum levels of TG, TC, LDL-C and insulin were significantly reduced (P<0.05), and the ISI was significantly increased (P<0.05) in high fat diet + SRLA group. But no statistically significant difference was found in the blood glucose among the 3 groups.

CONCLUSIONSRLA can significantly correct blood lipid and insulin disorders in hyperlipidemic New Zealand rabbits and prevent the occurrence of insulin resistance and hyperlipidemia.

Animals ; Blood Glucose ; metabolism ; Delayed-Action Preparations ; Hyperlipidemias ; blood ; drug therapy ; metabolism ; Insulin ; metabolism ; Lipids ; blood ; Male ; Rabbits ; Tablets ; Thioctic Acid ; administration & dosage ; pharmacology ; therapeutic use