Deacetylated nimbin analog N2 fortifies alloxan-induced pancreatic ß-cell damage in insulin-resistant zebrafish larvae by upregulating phosphoenolpyruvate carboxykinase (PEPCK) and insulin levels.

This study aims to evaluate the protective behaviour of N2, a semi-natural analog of nimbin, for its anti-diabetic efficacy against alloxan-induced oxidative damage and ß-cell dysfunction in in-vivo zebrafish larvae. A 500 µM of alloxan was exposed to zebrafish larvae for 24 h to induce oxidative stress in the pancreatic ß-cells and co-exposed with N2 to study the protection of N2 by inhibiting ROS by DCFH-DA, DHE and NDA staining along with Cellular damage, apoptosis and lipid peroxidation. The zebrafish was further exposed to 500 µM alloxan for 72 h to induce ß-cell destruction along with depleted glucose uptake and co-exposed to N2 to study the protective mechanism. Glucose levels were estimated, and PCR was used to verify the mRNA expression of phosphoenolpyruvate carboxykinase (PEPCK) and insulin. Alloxan induced (24 h) oxidative stress in the pancreatic ß-cells in which N2's co-exposure inhibited ROS by eliminating O-2 radicals and restoring the glutathione levels, thus preventing cellular damage and lipid peroxidation. The zebrafish exposed to 500 µM alloxan for 72 h was observed with ß-cell destruction along with depleted glucose uptake when stained with 2NBDG, wherein N2 was able to protect the pancreatic ß-cells from oxidative damage, promoted high glucose uptake and reduced glucose levels. N2 stimulated insulin production and downregulated PEPCK by inhibiting gluconeogenesis, attenuating post-prandial hyperglycemia. N2 may contribute to anti-oxidant protection against alloxan-induced ß-cell damage and anti-hyperglycemic activity, restoring insulin function and suppressing PEPCK expression.

Potential effect of Turbinaria decurrens acetone extract on the biochemical and histological parameters of alloxan-induced diabetic rats.

Upon Seeking natural and safe alternatives for synthetic medicines to treat many chronic diseases, seaweeds have offered a promising resource to produce numerous bioactive secondary metabolites. Through in vivo investigations, Turbinaria decurrens acetone extract (AE) revealed its antidiabetic activity against alloxan-induced diabetic rats. Treatment of rats with T. decurrens AE at 300 and 150 mg/Kg doses revealed antihyperglycemic activity by reducing the elevated blood glucose level. A remarkable decrease in the liver, kidney functions, and hyperlipidemia related to diabetes were also detected. Administration of the same extract also showed a recovery in body weight loss, total protein, albumin, and haemoglobin levels compared with untreated diabetic rats. Furthermore, treatment of rats with the same extract improved liver and pancreas histopathological disorders related to diabetes. These effects may be attributed to the presence of bioactive phytochemicals and antioxidant components in T. decurrens AE mainly cyclotrisiloxane, hexamethyl, and cyclic diterpene 3,7,11,15-tetramethyl-2-hexadecen-1-ol (phytol alcohol). Besides, other valuable secondary metabolites, as phenols, flavonoids, alkaloids, terpenoids, steroid and glycosides, which were documented and published by the same authors in a previous study. The obtained results in the present study recommended using T. decurrens AE in developing medicinal preparations for treatment of diabetes and its related symptoms.

A system-level approach to investigate alloxan-induced toxicity in microtubule-binding protein to lead type 2 diabetes mellitus.

Microtubule-associated protein tau (MAPT) is a key protein, which is mainly identified as an essential factor for microtubule dynamics and neuronal outgrowth. Though tau has several functions, regulation of insulin signaling is one among them to control type 2 diabetes. Abnormal expression of tau protein leads to hyperphosphorylation and is known as tauopathies. The presence of alloxan occurs in refined wheat flour, especially in various baking products such as parotta, a well-known South Indian dish. In this study, the reduced form of alloxan called dialuric acid can enter the beta cells of islets of Langerhans and binds MAPT to induce toxicity by hyperphosphorylating the tau protein, which ultimately causes destruction to pancreatic beta cells, and it leads to diabetes mellitus. Here, the toxic effects of dialuric acid targeting MAPT through in silico computational predictions have been investigated. The 3D structure of MAPT protein was constructed through I-Tasser, and it has been refined and validated by GalaxyRefine and PROCHECK. The structure of ligand was retrieved from PubChem. Molecular docking was accomplished by AutoDock 4.2 software, and the results indicate the strong binding affinity between dialuric acid and MAPT protein, and it showed a binding free energy (∆G) of - 3.72 kcal/mol. Dialuric acid binds with the active region SER 232 of MAPT whereby it hyperphosphorylates the protein to become toxic. Also, ADMET results strongly suggest that the compound dialuric acid possesses toxic property, and similarly, Ames test confirmed that it was found to be mutagenic. Thus, our results strongly revealed that dialuric acid was found to be toxic which could be able to damage the beta cells of the pancreas and abates insulin signaling, and finally, it leads to DM.

Endangered Lymphocytes: The Effects of Alloxan and Streptozotocin on Immune Cells in Type 1 Induced Diabetes.

Alloxan (ALX) and streptozotocin (STZ) are extensively used to induce type 1 diabetes (T1D) in animal models. This study is aimed at evaluating the differences in immune parameters caused by ALX and STZ. T1D was induced either with ALX or with STZ, and the animals were followed for up to 180 days. Both ALX and STZ induced a decrease in the total number of circulating leukocytes and lymphocytes, with an increase in granulocytes when compared to control mice (CT). STZ-treated mice also exhibited an increase in neutrophils and a reduction in the lymphocyte percentage in the bone marrow. In addition, while the STZ-treated group showed a decrease in total CD3+, CD4-CD8+, and CD4+CD8+ T lymphocytes in the thymus and CD19+ B lymphocytes in the pancreas and spleen, the ALX group showed an increase in CD4-CD8+ and CD19+ only in the thymus. Basal levels of splenic interleukin- (IL-) 1ß and pancreatic IL-6 in the STZ group were decreased. Both diabetic groups showed atrophy of the thymic medulla and degeneration of pancreatic islets of Langerhans composed of inflammatory infiltration and hyperemia with vasodilation. ALX-treated mice showed a decrease in reticuloendothelial cells, enhanced lymphocyte/thymocyte cell death, and increased number of Hassall's corpuscles. Reduced in vitro activation of splenic lymphocytes was found in the STZ-treated group. Furthermore, mice immunized with ovalbumin (OVA) showed a more intense antigen-specific paw edema response in the STZ-treated group, while production of anti-OVA IgG1 antibodies was similar in both groups. Thereby, important changes in immune cell parameters in vivo and in vitro were found at an early stage of T1D in the STZ-treated group, whereas alterations in the ALX-treated group were mostly found in the chronic phase of T1D, including increased mortality rates. These findings suggest that the effects of ALX and STZ influenced, at different times, lymphoid organs and their cell populations.

Therapeutic role of Rauwolfia serpentina in minimizing the risk of glycosylation and associated biomarkers in experimentally induced type 1 diabetic mice.

Present work investigates the effects of hydro-methanolic roots extract (HyMREt) of Rauwolfia serpentina in type 1 diabetic mice. Mice were divided into normal, diabetic, negative and positive controls (I-IV) and three test (HyMREt doses) groups (V-VII - 50, 100, &150mg/kg). Allocated treatment of each group was given orally for 14 days in overnight fasted state. Percent change in fasting blood glucose (FBG), body weights, body tissue weights, hepatic glycogen, total lipids, glycosylated hemoglobin (HbA1c), complete blood profile and antioxidant enzymes including catalase (CAT) and superoxide dismutase (SOD) were estimated. HyMREt doses produced meaningful (p<0.0001) reduction (-39 to -53%) in FBG. Hemoglobin (Hb) levels were raised, HbA1c were considerably decreased (4.5-3.77%) and glycosylation (HbA1c to Hb) ratio was expressively (p<0.0001) improved in test groups. Dose-wise improvement (p< 0.05) in total glycogen and decrement (p<0.05) in lipids were observed in livers of test groups. HyMREt significantly decreased (p<0.05) percent inhibition of SOD and CAT. HyMREt doses progressively (p<0.05) improved RBC and other hematological parameters while decrement was only noticed in leucocyte counts. Administration of test doses of HyMREt were significantly reduced the glycosylation, oxidative stress and anemia caused by alloxan intoxication in mice.

Rutin ameliorates metabolic acidosis and fibrosis in alloxan induced diabetic nephropathy and cardiomyopathy in experimental rats.

Diabetic nephropathy and cardiomyopathy are two major causes of mortality among patients with diabetes mellitus (DM). Since current diabetic medications are associated with various side effects, the naturally occurring plant-derived compounds are in demand. Bioflavonoids originating from vegetables and medicinal plants have beneficial effects on diabetes by improving glycemic control, lipid metabolism, and anti-oxidant status. The present study is focused on the effect of rutin against alloxan induced diabetic nephropathy and cardiomyopathy. Male albino Wistar rats were divided into four groups, each of six rats. Group I control rats received 0.9% saline as a single dose intraperitoneally. Group II rats were induced diabetes with a single dose of alloxan monohydrate (150 mg/kg body weight in 0.9% saline) intraperitoneally. Group III rats received 0.28 M of NH4Cl in drinking water for 3 days for the experimental induction of metabolic acidosis. Group IV rats were injected with a single dose of alloxan monohydrate (150 mg/kg bodyweight) and administered rutin hydrate (100 mg/kg) for a period of 4 weeks by oral gavage. Administration of rutin prevented urinary ketone body formation and decreased serum creatinine and urea levels in alloxan induced diabetic rats. Rutin supplementation reduced the levels of serum triglycerides and cholesterol in diabetic rats. Gene expression profiling of metabolic acidosis related genes (AQP2, AQP3 and V2R) and also histopathological results demonstrated the protective effect of rutin against diabetic ketoacidodis and fibrosis. The results of the present study revealed rutin administration prevents the progression of diabetic nephropathy and cardiomyopathy through amelioration of fibrosis and metabolic acidosis.

Genetic characterization of early renal changes in a novel mouse model of diabetic kidney disease.

Genetic factors influence susceptibility to diabetic kidney disease. Here we mapped genes mediating renal hypertrophic changes in response to diabetes. A survey of 15 mouse strains identified variation in diabetic kidney hypertrophy. Strains with greater (FVB/N(FVB)) and lesser (C57BL/6 (B6)) responses were crossed and diabetic F2 progeny were characterized. Kidney weights of diabetic F2 mice were broadly distributed. Quantitative trait locus analyses revealed diabetic mice with kidney weights in the upper quartile shared alleles on chromosomes (chr) 6 and 12; these loci were designated as Diabetic kidney hypertrophy (Dkh)-1 and -2. To confirm these loci, reciprocal congenic mice were generated with defined FVB chromosome segments on the B6 strain background (B6.Dkh1/2f) or vice versa (FVB.Dkh1/2b). Diabetic mice of the B6.Dkh1/2f congenic strain developed diabetic kidney hypertrophy, while the reciprocal FVB.Dkh1/2b congenic strain was protected. The chr6 locus contained the candidate gene; Ark1b3, coding aldose reductase; the FVB allele has a missense mutation in this gene. Microarray analysis identified differentially expressed genes between diabetic B6 and FVB mice. Thus, since the two loci identified by quantitative trait locus mapping are syntenic with regions identified for human diabetic kidney disease, the congenic strains we describe provide a valuable new resource to study diabetic kidney disease and test agents that may prevent it.

Co-Transplantation of Pancreatic Islet Cells and Mesenchymal Bone Marrow Precursors on Titanium Nickelide Scaffolds in Alloxan-Induced Diabetes Mellitus.

We studied therapeutic activity of co-transplantation of allogeneic pancreatic islet cells and mesenchymal bone marrow progenitors on TiNi scaffolds in Wistar rats with experimental alloxan-induced diabetes mellitus. In preliminary experiments with co-culturing of cells in different proportions followed by their transplantation on tissue-engineered constructs, the optimum ratio of these cells was determined - 3:1. Regeneration was assessed by biochemical methods by the blood levels of glucose and glycosylated hemoglobin on days 15, 30, and 5. In the group with combined cell transplantation on TiNi scaffold, normalization of the studied biochemical parameters occurred earlier than after monotherapy with allogenic islet cells and was associated with an increase in animal lifespan. Normalization of the parameters of bone marrow hemopoiesis, in particular, the number of myelokaryocytes and erythroblasts was also noted.

Antidiabetic and antidyslipidemic potential of Echinops echinatus in rat models of type I and type II diabetes.

Echinops echinatus is traditionally an important plant that finds its extensive use as a diuretic, anti-inflammatory, anti-pyretic, nerve tonic, abortifacient, aphrodisiac, antiasthmatic, and antidiabetic agent. The current study investigates protection against the hyperglycemia and dyslipidemia in alloxan-induced (type I diabetes) and fructose-fed insulin resistance (type II diabetes) models of diabetes treated with aqueous methanolic root extract of E. echinatus (Ee.Cr). Albino rats were treated orally with Ee.Cr at doses 100, 300 and 500mg/kg. The fasting blood glucose was measured by glucometer, while standard kits were used to determine the levels of serum total cholesterol, triglycerides and HDL. The administration of Ee.Cr significantly (P<0.001) reduced the FBG concentration in a dose-dependent pattern in alloxan-induced and fructose-fed diabetic rats. The Ee.Cr also corrected the dyslipidemia associated with fructose and alloxan-induced diabetes by significantly (P<0.001) decreasing the concentration of serum total cholesterol, triglycerides, and LDL and by increasing HDL concentration. Ee.Cr also significantly (P<0.001) improved the glucose tolerance in fructose-fed rats. We conclude that Ee.Cr has antidiabetic and antidyslipidemic effects in both insulin-dependent alloxan-induced diabetes and fructose-induced insulin resistance diabetes rat models.

Activation of insulin receptors and IGF-1 receptors in COLO-205 colon cancer xenografts by insulin and insulin analogue X10 does not enhance growth under normo- or hypoglycaemic conditions.

AIMS/HYPOTHESIS: Recent studies with normal rats and mouse allograft models have reported that insulin and insulin analogues do not activate the IGF-1 receptor in vivo, and that this characteristic therefore cannot be responsible for the increased incidence of mammary tumours observed for the insulin analogue X10 in chronic toxicity studies with Sprague Dawley rats. This is in clear contrast to reports of insulin and insulin analogues in vitro. Clarification of this is important for understanding the mechanisms behind possible growth-promoting effects of insulin analogues, and will have implications for the development of novel insulin analogues. METHODS: We established a xenograft model in BALB/c nude mice with the human colon cancer cell line COLO-205, which expresses human insulin and IGF-1 receptors, and explored the acute and chronic effects of treatment with supra-pharmacological doses of human insulin, insulin analogue X10 and human IGF-1. With a novel antibody, acute IGF-1 receptor activation was also examined in various tissues from normal rats treated with human insulin, insulin analogue X10 or human IGF-1. Finally, the effects of pharmacologically relevant doses of human insulin and insulin analogue X10 on receptor activation and growth of COLO-205 xenograft were explored in BALB/c nude mice with alloxan-induced hyperglycaemia. RESULTS: In normal rats and in BALB/c nude mice bearing a COLO-205 cell xenograft, treatment with supra-pharmacological doses of human insulin, insulin analogue X10 or human IGF-1 resulted in activation of insulin receptors as well as IGF-1 receptors. Treatment of diabetic nude mice with pharmacologically relevant doses of human insulin or insulin analogue X10, which decreased blood glucose from hyperglycaemic levels to the normoglycaemic range, did not increase IGF-1 receptor activation. Furthermore, repeated treatment with supra-pharmacological as well as pharmacological doses of human insulin or insulin analogue X10 did not influence the growth of COLO-205 xenografts. CONCLUSIONS/INTERPRETATION: This study demonstrates that activation of IGF-1 receptors in cancer cells by insulin and insulin analogues cannot be considered as a purely in vitro phenomenon. It does occur in vivo in animal models, although only after treatment with supra-pharmacological doses. Furthermore, treatment with insulin or insulin analogue X10 did not influence the growth of COLO-205 xenografts under normo- or hypoglycaemic conditions. Further studies are needed before a conclusion can be reached on whether IGF-1 receptor activation by insulin analogues correlates with increased growth in vivo.

Comparison of Acute Gene Expression Profiles of Islet Cells Obtained via Laser Capture Microdissection between Alloxan- and Streptozotocin-treated Rats.

To identify the molecular profiles of islets from alloxan (ALX)- and streptozotocin (STZ)-treated rats, a microarray-based global gene expression analysis was performed on frozen islets isolated via laser capture microdissection. At 6 weeks old, rats were injected with ALX (40 mg/kg) or STZ (50 or 100 mg/kg) and then euthanized 24 hr later. Histopathological analysis showed ß-cell necrosis, macrophage infiltration, and islet atrophy. The extent of these changes was more notable in the STZ groups than in the ALX group. Transcriptome analysis demonstrated a significant up- or downregulation of cell cycle arrest-related genes in the p53 signaling pathway. Cyclin D2 and cyclin-dependent kinase inhibitor 1A, mediators of G1 arrest, were remarkably altered in STZ-treated rats. In contrast, cyclin-B1 and cyclin-dependent kinase 1, mediators of G2 arrest, were remarkably changed in ALX-treated rats. Genes involved in the intrinsic mitochondria-mediated apoptotic pathway were upregulated in the ALX and STZ groups. Moreover, heat-shock 70 kDA protein 1A ( Hspa1a), Hsp90ab1, and Hsph1 were upregulated in ALX-treated rats, suggesting that ALX treatment injures ß cells via endoplasmic reticulum stress. These results contribute to a better understanding of gene expression in the pathogenesis of islet toxicity.

Flavonoid 8-O-Glucuronides from the Aerial Parts of Malva verticillata and Their Recovery Effects on Alloxan-Induced Pancreatic Islets in Zebrafish.

Malva verticillata (Cluster mallow), a leafy vegetable that has been popular in East Asia for a long time, has also been used in herbal teas and medicines. The aqueous fraction of the aerial parts of Malva verticillata, exhibiting a very high quantity of flavonoids compared to the EtOAc and n-BuOH fractions, exhibited significant recovery effects on pancreatic islets damaged by alloxan in zebrafish larvae. Thus, the bioactive components responsible for this anti-diabetic activity were investigated. A new flavonoid glucuronide (1) and five known flavonoids were isolated from the aqueous fraction. Based on several spectroscopic methods, compound 1 was identified to be nortangeretin-8-O-ß-D-glucuronide, and was named malvaflavone A. The A-ring of compound 1 had a 5,6,7,8-tetrahydroxy moiety, which rarely occurs in plant systems. Also 8-O-glucuronide attached to the flavonoid moiety was rarely occurred in plant system. Compounds 1, 3, 4, and 6 significantly improved the pancreatic islet size in zebrafish at 0.1 µM, and compounds 1 and 6 were found to block ß-cell K⁺ channels in experiments with diazoxide. In ABTS, ORAC, and SOD assays, compounds 1-5 exhibited high anti-oxidant activities compared with quercetin and BHA (positive controls), indicating that the 8-O-glucuronide attached to the flavonoid moiety is a key structure for the expression of anti-oxidant activity. This is the first report of the isolation of compounds 1-6 from M. verticillata as well evaluated for anti-diabetic and anti-oxidant ativities.

Protective effect of vitamin E against alloxan-induced mouse hyperglycemia.

BACKGROUND: Alloxan induces oxidative stress and hyperglycemia in animal models. Acatalasemic (catalase deficiency) mice are susceptible to alloxan-induced hyperglycemia. As the incidence of hyperglycemia induced by alloxan was reportedly improved when mice were fed a vitamin E supplemented diet, this protective effect was examined. METHODS: Acatalasemic and normal mice fed a vitamin E supplemented diet were treated with alloxan. The pancreas were examined with microscopy. We also isolated pancreatic islets of normal mice treated with alloxan. The glucose stimulated insulin secretion was examined. RESULTS: Vitamin E powerfully ameliorated the increase in apoptosis. Vitamin E increases insulin amounts secreted from pancreatic cells, but does not ameliorate the regulation of the glucose stimulated insulin secretion. CONCLUSIONS: It is suggested that the difference in the mice fed vitamin E supplemented diet is due to an increase of insulin secretion and that vitamin E supplementation may have a role in helping to slow the stages of diabetes mellitus.

A combination of cytokines EGF and CNTF protects the functional beta cell mass in mice with short-term hyperglycaemia.

AIMS/HYPOTHESIS: When the beta cell mass or function declines beyond a critical point, hyperglycaemia arises. Little is known about the potential pathways involved in beta cell rescue. As two cytokines, epidermal growth factor (EGF) and ciliary neurotrophic factor (CNTF), restored a functional beta cell mass in mice with long-term hyperglycaemia by reprogramming acinar cells that transiently expressed neurogenin 3 (NGN3), the current study assesses the effect of these cytokines on the functional beta cell mass after an acute chemical toxic insult. METHODS: Glycaemia and insulin levels, pro-endocrine gene expression and beta cell origin, as well as the role of signal transducer and activator of transcription 3 (STAT3) signalling, were assessed in EGF+CNTF-treated mice following acute hyperglycaemia. RESULTS: The mice were hyperglycaemic 1 day following i.v. injection of the beta cell toxin alloxan, when the two cytokines were applied. One week later, 68.6 ± 4.6% of the mice had responded to the cytokine treatment and increased their insulin(+) cell number to 30% that of normoglycaemic control mice, resulting in restoration of euglycaemia. Although insulin(-) NGN3(+) cells appeared following acute EGF+CNTF treatment, genetic lineage tracing showed that the majority of the insulin(+) cells originated from pre-existing beta cells. Beta cell rescue by EGF+CNTF depends on glycaemia rather than on STAT3-induced NGN3 expression in acinar cells. CONCLUSIONS/INTERPRETATION: In adult mice, EGF+CNTF allows the rescue of beta cells in distress when treatment is given shortly after the diabetogenic insult. The rescued beta cells restore a functional beta cell mass able to control normal blood glucose levels. These findings may provide new insights into compensatory pathways activated early after beta cell loss.

Imbalanced Macrophage and Dendritic Cell Activations in Response to Candida albicans in a Murine Model of Diabetes Mellitus.

Bloodstream infections caused by Candida species are responsible for high morbidity and mortality, and diabetes mellitus (DM) is an important underlying disease in candidemia episodes. Although DM patients show an enhanced proinflammatory profile, they are highly susceptible to mycobacterial and mycotic infections. Attempting to understand this paradox, we investigated if imbalanced macrophage and dendritic cell (DC) activations could be associated to high incidence and/or severity of Candida albicans infection in the hypoinsulinemia-hyperglycemia (HH) milieu. HH alloxan-induced mice were infected with C. albicans and peritoneal aderent phagocytes were co-cultured with or without lipopolyssaccharide or heat-killed C. albicans, and the production of cytotoxic metabolites, cytokines, and chemokines was evaluated. We also evaluated the surface expression of MHC-II and CD86 in splenic DCs. Our findings showed that both uninfected and C. albicans-infected HH mice showed less production of CCL2 and reduced expression of CD86 by peritoneal phagocytes and splenic DCs, respectively.

Functional role of myocardial electrical remodeling in diabetic rabbits.

The objective of the study was to investigate the role of electrical remodeling of the ventricular myocardium in hemodynamic impairment and the development of arrhythmogenic substrate. Experiments were conducted with 11 healthy and 12 diabetic (alloxan model, 4 weeks) rabbits. Left ventricular pressure was monitored and unipolar electrograms were recorded from 64 epicardial leads. Aortic banding was used to provoke arrhythmia. The diabetic rabbits had prolonged QTc, with activation-recovery intervals (surrogates for repolarization durations) being relatively short on the left ventricular base and long on the anterior apical portions of both ventricles (P < 0.05). In the diabetic rabbits, a negative correlation (-0.726 to -0.817) was observed between dP/dt(max), dP/dt(min), and repolarization dispersions. Under conditions of systolic overload (5 min), tachyarrhythmias were equally rare and the QTc and activation-recovery intervals were shortened in both groups (P < 0.05), whereas QRS was prolonged in the diabetic rabbits only. The repolarization shortening was more pronounced on the apex, which led to the development of apicobasal and interventricular end of repolarization gradients in the healthy animals, and to the flattening of the repolarization profile in the diabetic group. Thus, the diabetes-related pattern of ventricular repolarization was associated with inotropic and lusitropic impairment of the cardiac pump function.

Insulin influences autophagy response distinctively in macrophages of different compartments.

BACKGROUND/AIMS: Diabetes mellitus (DM) is characterized by hyperglycemia, associated to a lack or inefficiency of the insulin to regulate glucose metabolism. DM is also marked by alterations in a diversity of cellular processes that need to be further unraveled. In this study, we examined the autophagy pathway in diabetic rat macrophages before and after treatment with insulin. METHODS: Bone marrow-derived macrophages (BMM), bronchoalveolar lavage (BAL) and splenic tissue of diabetic male Wistar rats (alloxan, 42 mg/kg, i.v., 10 days) and control rats (physiological saline, i.v.). Some diabetic rats were given neutral protamine Hagedorn insulin (4 IU, s.c.) 8 h before experiments. For characterization of the model and evaluation of the effect of insulin on the autophagic process, the following analyzes were performed: (a) concentrations of cytokines: interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, IL-6, IL-4, IL-10, cytokine-induced neutrophil chemoattractant (CINC)-1 and CINC-2 in the BAL supernatant was measured by ELISA; (b) characterization of alveolar macrophage (AM) of the BAL as surface antigens (MHCII, pan-macrophage KiM2R, CD11b) and autophagic markers (protein microtubule-associated light chain (LC)3, autophagy protein (Atg)12 by flow cytometry and confocal microscopy (c) study of macrophages differentiated from the bone marrow by flow cytometry and confocal microscopy (d) histology of the spleen by immunohistochemistry associated with confocal microscopy. RESULTS: Interestingly, insulin exerted antagonistic effects on macrophages from different tissues. Macrophages from bronchoalveolar lavage (BAL) enhanced their LC3 autophagosome bound content after treatment with insulin whereas splenic macrophages from red pulp in diabetic rats failed to enhance their Atg 12 levels compared to control animals. Insulin treatment in diabetic rats did not change LC3 content in bone marrow derived macrophages (BMM). M1 and M2 macrophages behaved accordingly to the host they were derived from. Diabetic M1 BMM had their LC3 vesicle-bound content diminished and M2 BMM enhanced their LC3 levels and insulin treatment failed to rescue autophagy to control levels. Insulin normalizes CINC-2 level but does not modulate autophagy markers. CONCLUSION: Taking these results together, diabetic macrophages derived from different compartments show different levels of autophagy markers compared to healthy animals, therefore, they suffer distinctively in the absence of insulin.

Oxidative stress increased hepatotoxicity induced by nano-titanium dioxide in BRL-3A cells and Sprague-Dawley rats.

Extensive studies have shown that titanium dioxide (TiO2 ) nanomaterials (NMs) can cause toxicity in vitro and in vivo under normal conditions. However, an adverse effect induced by nano-TiO2 in many diseased conditions, typically characterized by oxidative stress (OS), remains unknown. We investigated the toxicity of nano-TiO2 in rat liver cells (BRL-3A) and Sprague-Dawley (SD) rat livers under OS conditions, which were generated using hydrogen peroxide (H2 O2 ) in vitro and alloxan in vivo, respectively. In vitro results showed that cell death ratios after nano-TiO2 exposure were significantly enhanced (up to 2.62-fold) in BRL-3A cells under OS conditions, compared with normal controls. Significant interactions between OS conditions and nano-TiO2 resulted in the rapid G0/G1 to S phase transition and G2/M arrest, which were opposite to G0/G1 phase arrest in cells after NMs exposure only. In vivo results showed that obvious pathological changes in rat livers and the increased activities of four enzymes (i.e. aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and alkaline phosphatase) owing to liver damage after nano-TiO2 exposure under OS conditions, compared with their healthy controls. In addition, compared with increased hepatotoxicity after nano-TiO2 exposure, micro-TiO2 showed no adverse effects to cells and rat livers under OS conditions. Our results suggested that OS conditions synergistically increase nano-TiO2 induced toxicity in vitro and in vivo, indicating that the evaluation of nanotoxicity under OS conditions is essentially needed prior to various applications of NMs in foods, cosmetics and potential treatment of diseases.

[Protective effect of 3-oxypyridine and succinic acid derivatives under conditions of acute alloxan-induced intoxication in mice].

Protective action of 3-oxypiridine and succinic acid derivatives (emoxipin, reamberin and mexidol) was studied in mice under acute alloxan-induced intoxication conditions. All these drugs exhibited protective action with respect to hyperglycemia and hyperglycemia-connected elongation of desperate behavior in the tail-suspension test and reduced activity level on the open field test. Mexidol exceeded emoxipin in the dose range of protecting action with respect to alloxan-induced hyperglycemia and was superior to reamberin in the treatment of desperate behavior in the tail-suspension test.

[Wound-healing effect of carbopol hydrogels in rats with alloxan diabetes model].

The effects of 0.5% hydrogels of acrylic polymers (carbopol), antibiotic ointment based on polyethylene oxides (levomekol), silver-containing creams (dermazin and argosulfan), silver sulfadiazine ointment with epidermal growth factor (ebermin), and wound-covering fabric of antibacterial cellulose with poviargol and zero-valent silver (aquacell-Ag) on skin repair processes have been evaluated in comparative experiments on rats. The wound-healing effects were characterized by the time of cleansing and epithelization, rate of suppuration, index of healing, and skin impedance under conditions of necrotic skin lesions on the background of diabetes. It is established that local application of carbopol hydrogels modified by electric (frequency-modulated) signal with antiseptics (poviargol) and nanostructural components (natural fullerene complex) shortens the period of wound cleansing from detritus on the background of decompensated diabetes by 3.6 days (p > 0.05), accelerates healing by 8.4 days (p < 0.05), reduces the frequency of suppuration by 23.3% (p < 0.05), exhibits strong bactericidal effect against wound infections by pathogens, and restores tissue impedance. Thus, hydrogels based on low-crosslinked acrylic polymers are a promising basis of wound-healing formulations for the treatment of necrotic lesions on the background of diabetic foot syndrome.