Alkaline, Endo III and FPG modified comet assay as biomarkers for the detection of oxidative DNA damage in rats with experimentally induced diabetes

Combination treatment of zinc and selenium intervention ameliorated BPA-exposed germ cell damage in SD rats: elucidation of molecular mechanisms

Bisphenol A (BPA) is a commonly used environmental toxicant, is easily exposed to the human body and causes testicular damage, sperm abnormalities, DNA damage and apoptosis, and interferes in the process spermatogenesis and steroidal hormone production along with obstruction in testes and epididymis development. Zinc (Zn), a potent regulator of antioxidant balance, is responsible for cellular homeostasis, enzymes and proteins activities during spermatogenesis for cell defence mechanisms in the testes. Selenium (Se) is required for spermatogenesis, antioxidant action and in the activities of different selenoproteins. Both Zn and Se are essential simultaneously for the proper regulation of spermatogenesis and sperm maturation as well as protection against chemical and disease-associated germ cell toxicity. Thus, the study aimed to understand the importance and beneficial effect of Zn and Se co-treatment against BPA-exposed testicular damage in rats. BPA 100 and 200 mg/kg/day was exposed through an oral gavage. Zn (3 mg/kg/day) i.p. and Se (0.5 mg/kg/day) i.p. were injected for 8 weeks. The testicular toxicity was evaluated by measuring body and organs weight, biochemical investigations, sperm parameters, testicular and epididymal histopathology, quantification DNA damage by halo assay, DNA breaks (TUNEL assay), immunohistochemistry and western blot. Results revealed that Zn and Se co-treatment ameliorated BPA-associated male gonadal toxicity in rat as revealed by decreased SGPT, SGOT and BUN levels in serum, reduced testes and epididymis tissue injury, DNA breaks, apoptosis, expressions of 8-OHdG, γ-H2AX and NFκB with an increased serum testosterone and catalase levels. These findings suggest that Zn and Se co-treatment could be a beneficial and protective option against BPA-exposed testicular and epididymal toxicity.

Protective role of eugenol against diabetes-induced oxidative stress, DNA damage, and apoptosis in rat testes

Diabetes mellitus, a metabolic disorder alters gonadal development and spermatogenesis, reactive oxygen species production, DNA damage, and apoptosis, which subsequently lead to male subfertility. Eugenol is an antioxidant, traditionally used as medication for digestive disorders and antioxidant therapy, decrease transport of glucose from GIT to systemic circulation. This experiment was aimed to decipher cellular and molecular insights of eugenol in protecting diabetic germ cells in rats. Rats were assigned randomly into five groups: control, eugenol control (Eugenol 400; EUG), diabetic (DIA), diabetic + eugenol 100 (DIA + EUG 100), and diabetic + eugenol 400 (DIA + EUG 400). EUG 400 and DIA + EUG 400 groups received 400 mg/kg eugenol orally. DIA + EUG 100 group received 100 mg/kg eugenol. Treatment was conducted for 4 weeks. Type 1 diabetes was induced by injecting a single i.p. dose of streptozotocin (55 mg/kg). Morphometric, biochemical, sperm parameters, oxidative stress, hormonal levels, histopathology, and fibrosis in the testis and epididymis, were evaluated. DNA damage was evaluated using halo and comet assays; DNA fragmentation and apoptosis using TUNEL assay. Eugenol treatment significantly normalized biochemical parameters, reduced MDA while increased albumin and GSH levels in diabetes. Eugenol significantly increased sperm numbers, motility and attenuated abnormal sperm head morphology in diabetes. Moreover, eugenol significantly reversed diabetes-induced cellular damages, altered spermatogenesis, and collagen deposition in testis and epididymis. It also significantly attenuated diabetes-associated DNA breaks and apoptosis. These findings suggest that 4 weeks treatment with 400 mg/kg of eugenol could be beneficial for diabetic patients to prevent subfertility.

Dalbergiella welwitschia (Baker) Baker f. alkaloid-rich extracts attenuate liver damage in streptozotocin-induced diabetic rats

This experiment was conducted to evaluate the Dalbergiella welwitschia alkaloid-rich extracts on liver damage in streptozotocin-induced diabetic rats. Hence, to induce diabetes, 45 mg/kg body weight of streptozotocin was intraperitoneally injected into the Wistar rats. Subsequently, 5 % (w/v) of glucose water was given to the induced animals for 24 h. Thus, the animals (48) were grouped into five groups (n = 8), containing normal control (NC), diabetic control (DC), diabetic rats placed on low (50 mg/kg body weight) and high (100 mg/kg body weight) doses of D. welwitschi alkaloid-rich leaf extracts (i.e. DWL and DWH respectively), and diabetic rats administered 200 mg/kg body weight of metformin (MET). The animals were sacrificed on the 21st day of the experiment, blood and liver were harvested, and different liver damage biomarkers were evaluated. The results obtained demonstrated that diabetic rats administered DWL, DWH and MET significantly (p < 0.05) increased hepatic AST, ALT, albumin, SOD, CAT, GSH, and GPX levels when compared to DC with no significant (p > 0.05) different when compared with NC. Also, diabetic rats administered DWL, DWH and MET revealed a significant (p < 0.05) decrease in GGT and MDA levels, as well as, fragmented DNA and protein carbonyl levels when compared to DC with no significant (p > 0.05) different when compared with NC. In addition, histological examination revealed that diabetic rats placed on DWL, DWH and MET normalized the hepatocytes. Consequently, it can be inferred that alkaloid-rich extracts from D. welwitschi leaf could be helpful in improving liver damage associated with diabetes mellitus rats.

Salbutamol ameliorates skeletal muscle wasting and inflammatory markers in streptozotocin (STZ)-induced diabetic rats

Diabetes accelerates muscle atrophy, leading to the deterioration of skeletal muscles. This study aimed to assess the potential of the β2-adrenoceptor agonist, salbutamol (SLB), to alleviate muscle atrophy in streptozotocin (STZ)-induced diabetic rats. Male Sprague Dawley rats were randomized into four groups (n=6): control, SLB, STZ (55 mg/kg, single i.p.), and STZ + SLB (6 mg/kg, orally for 4 weeks). After the final SLB dose, animals underwent tests to evaluate muscle strength and coordination, including forelimb grip strength, wire-hanging, actophotometer, rotarod, and footprint assessments. Rats were then sacrificed, and serum and gastrocnemius (GN) muscles were collected for further analysis. Serum evaluations included proinflammatory markers (tumor necrosis factor α, interleukin-1β, interleukin-6), muscle markers (creatine kinase, myostatin), testosterone, and lipidemic markers. Muscle oxidative stress (malonaldehyde, protein carbonyl), antioxidants (glutathione, catalase, superoxide dismutase), and histology were also performed. Additionally, 1H nuclear magnetic resonance serum profiling was conducted. SLB notably enhanced muscle grip strength, coordination, and antioxidant levels, while reduced proinflammatory markers and oxidative stress in STZ-induced diabetic rats. Reduced serum muscle biomarkers, increased testosterone, restored lipidemic levels, and improved muscle cellular architecture indicated SLB's positive effect on muscle condition in diabetic rats. Metabolomics profiling revealed that the STZ group significantly increased the phenylalanine-to-tyrosine ratio (PTR), lactate-to-pyruvate ratio (LPR), acetate, succinate, isobutyrate, and histidine. SLB administration restored these perturbed serum metabolites in the STZ-induced diabetic group. In conclusion, salbutamol significantly protected against skeletal muscle wasting in STZ-induced diabetic rats.

DNA damage response signaling: A common link between cancer and cardiovascular diseases

DNA damage response (DDR) signaling ensures genomic and proteomic homeostasis to maintain a healthy genome. Dysregulation either in the form of down- or upregulation in the DDR pathways correlates with various pathophysiological states, including cancer and cardiovascular diseases (CVDs). Impaired DDR is studied as a signature mechanism for cancer; however, it also plays a role in ischemia-reperfusion injury (IRI), inflammation, cardiovascular function, and aging, demonstrating a complex and intriguing relationship between cancer and pathophysiology of CVDs. Accordingly, there are increasing number of reports indicating higher incidences of CVDs in cancer patients. In the present review, we thoroughly discuss (1) different DDR pathways, (2) the functional cross talk among different DDR mechanisms, (3) the role of DDR in cancer, (4) the commonalities and differences of DDR between cancer and CVDs, (5) the role of DDR in pathophysiology of CVDs, (6) interventional strategies for targeting genomic instability in CVDs, and (7) future perspective.

Dietary zinc deficient condition increases the Bisphenol A toxicity in diabetic rat testes

Bisphenol A (BPA) is a widely used endocrine disrupter that causes male reproductive dysfunction in humans and rodents. Diabetes-induced hyperglycemia alters spermatogenesis and antioxidant status, which negatively impacts male fertility in adults. Zinc (Zn) deficiency is a global health concern maintaining the testicular structure and functions in developing gonads. The present experiment was designed to investigate the role of Zn deficiency on BPA-induced germ cell and male gonadal toxicity in diabetic conditions. Rats were randomly divided into eight different groups - control (normal feed and water), BPA (10 mg/kg/day), ZDD (fed with a Zn-deficient diet), DIA (diabetic), BPA+ZDD, BPA+DIA, ZDD+DIA and BPA+ZDD+DIA for four weeks. Animals' body and organ weight, sperm count, motility and sperm morphology were examined; testes and epididymis histopathology were investigated. Testicular DNA damage and sperm apoptosis were evaluated by halo and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays respectively. Testicular catalase and octamer-binding transcription factor 4 (OCT4) expressions were evaluated by western blot analysis. The present results demonstrated that dietary Zn-deficient condition significantly increased the BPA-induced testicular, epididymal and sperm toxicity in diabetic rats due to hypogonadism, increased sperm abnormalities, epididymis, testicular structure and DNA damages, sperm apoptosis as well as decreased testicular catalase and OCT4 expressions. The present results revealed that dietary Zn-deficient condition exacerbated the BPA-induced testicular and epididymal toxicity as well as perturbed the general male reproductive health in diabetic rats.

Interspecific differences in oxidative DNA damage after hydrogen peroxide exposure of sea urchin coelomocytes

Interspecific comparison of DNA damage can provide information on the relative vulnerability of marine organisms to toxicants that induce oxidative genotoxicity. Hydrogen peroxide (H2O2) is an oxidative toxicant that causes DNA strand breaks and nucleotide oxidation and is used in multiple industries including Atlantic salmon aquaculture to treat infestations of ectoparasitic sea lice. H2O2 (up to 100 mM) can be released into the water after sea lice treatment, with potential consequences of exposure in nontarget marine organisms. The objective of the current study was to measure and compare differences in levels of H2O2-induced oxidative DNA damage in coelomocytes from Scottish sea urchins Echinus esculentus, Paracentrotus lividus, and Psammechinus miliaris. Coelomocytes were exposed to H2O2 (0-50 mM) for 10 min, cell concentration and viability were quantified, and DNA damage was measured by the fast micromethod, an alkaline unwinding DNA method, and the modified fast micromethod with nucleotide-specific enzymes. Cell viability was >92% in all exposures and did not differ from controls. Psammechinus miliaris coelomocytes had the highest oxidative DNA damage with 0.07 ± 0.01, 0.08 ± 0.01, and 0.07 ± 0.01 strand scission factors (mean ± SD) after incubation with phosphate-buffered saline, formamidopyrimidine-DNA glycosylase, and endonuclease-III, respectively, at 50 mM H2O2. Exposures to 0.5 mM H2O2 (100-fold dilution from recommended lice treatment concentration) induced oxidative DNA damage in all three species of sea urchins, suggesting interspecific differences in vulnerabilities to DNA damage and/or DNA repair mechanisms. Understanding impacts of environmental genotoxicants requires understanding species-specific susceptibilities to DNA damage, which can impact long-term stability in sea urchin populations in proximity to aquaculture farms.

L-carnitine Attenuates DNA Damage and Oxidative Stress in Diabetic Animals

Background: Diabetes is a metabolic disorder characterized by high plasma glucose levels. In this disease, increased production of reactive oxygen species (ROS) results in DNA damage and multiple complications. L-carnitine (LC) has shown a potent antioxidant activity that may reduce oxidative stress. Objectives: This study aims at assaying the effect of LC on DNA damage in streptozotocin-induced diabetic rats and evaluating the changes in antioxidant markers and liver function enzymes after the administration of LC . Methods: In the present study, for induction of diabetes, we injected a single dose of streptozotocin (65 mg/kg) by the intraperitoneal route, and diabetic rats were treated with LC 200, 300, and 400 mg/kg daily for 3 weeks. We detected the DNA damage at 7, 14, and 21 days after induction diabetes by the comet assay method. The blood glucose level, plasma alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were tested. Also, we measured the activity levels of superoxide dismutase (SOD) and intracellular glutathione (GSH). Results: The results of this study demonstrated the increasing amount of DNA damage with the amount and duration of hyperglycemia. L-carnitine treatment significantly decreased the parameters of genotoxicity such as % DNA in the tail, tail length, and tail moment over time. Moreover, the treatment of diabetic rats with LC 300 and 400 mg/kg/day after 21 days led to a remarkable decrease in blood glucose than diabetic rats. Also, we observed that LC can ameliorate enzyme liver function and reduce oxidative stress via enhancement of GSH and SOD levels. Conclusions: The results of this study indicated the protective effect of LC against DNA damage and oxidative stress in diabetic rats.

Evaluation of DNA damage induced by ionizing radiation from myocardial perfusion imaging: a pilot study

Background

As patient exposure to ionizing radiation raises concern about malignancy risks, this study evaluated the effect of ionizing radiation on patients undergoing myocardial perfusion imaging (MPI) using the comet assay, a method for detection of DNA damage.

Methods

Patients without cancer, acute or autoimmune diseases, recent surgery or trauma, were studied. Gated single-photon myocardial perfusion imaging was performed with Tc-99m sestamibi. Peripheral blood was collected before radiotracer injection at rest and 60–90 min after injection. Single-cell gel electrophoresis (comet assay) was performed with blood lymphocytes to detect strand breaks, which determine a “comet tail” of variable size, visually scored by 3 observers in a fluorescence microscope after staining (0: no damage, no tail; 1: small damage; 2: large damage; 3: full damage). A damage index was calculated as a weighted average of the cell scores.

Results

Among the 29 individuals included in the analysis, age was 65.3 ± 9.9 years and 18 (62.1%) were male. The injected radiotracer dose was 880.6 ± 229.4 MBq. Most cells (approximately 70%) remained without DNA fragmentation (class 0) after tracer injection. There were nonsignificant increases of classes 1 and 2 of damage. Class 3 was the least frequent both before and after radiotracer injection, but displayed a significant, 44% increase after injection.

Conclusion

While lymphocytes mostly remained in class 0, an increase in class 3 DNA damage was detected. This may suggest that, despite a probable lack of biologically relevant DNA damage, there is still a need for tracer dose reductions in MPI.

DNA damage and repair on hematopoietic stem cells: impact of oxidative stress in renovascular hypertension

BACKGROUND

This study investigated oxidative damage to bone marrow cells in the pathogenesis of renovascular hypertension (RH).

METHODS

Male C57BL/6 J mice (10-week-old and ~23 g) were divided into two groups: Sham-operated and 2K1C, which has a stainless-steel clip placed around the left renal artery. After twenty-eight days, the animals were anesthetized for hemodynamic measurements and bone marrow cells isolation. The intracellular production of ROS, DNA damage, and DNA repair kinetics were evaluated.

RESULTS

Our results show that RH increases HSCs ROS production and that the 2K1C group showed a significant reduction of HSCs in the G0/G1 phase, increased p53 expression, DNA fragmentation, low DNA repair capacity, and a higher percentage of apoptotic cells when compared with the Sham group.

CONCLUSIONS

Our data imply that RH can compromise the hematopoiesis by increased oxidative stress leading to impaired DNA repair activity. Furthermore, this study provides new insights into the influence of hypertension on bone marrow homeostasis. This study showed for the first time that RH leads to oxidative damage, including genotoxic, to bone marrow cells. Thus, these findings provide new insights into the consequences of RH on bone marrow cells.

Enhanced antitumor effect of L-buthionine sulfoximine or ionizing radiation by copper complexes with 2,2´-biquinoline and sulfonamides on A549 2D and 3D lung cancer cell models

Two ternary copper(II) complexes with 2,2'-biquinoline (BQ) and with sulfonamides: sulfamethazine (SMT) or sulfaquinoxaline (SDQ) whose formulae are Cu(SMT)(BQ)Cl and Cu(SDQ)(BQ)Cl·CH₃OH, in what follows SMTCu and SDQCu, respectively, induced oxidative stress by increasing ROS level from 1.0 μM and the reduction potential of the couple GSSG/GSH². The co-treatment with L-buthionine sulfoximine (BSO), which inhibits the production of GSH, enhanced the effect of copper complexes on tumor cell viability and on oxidative damage. Both complexes generated DNA strand breaks given by-at least partially-the oxidation of pyrimidine bases, which caused the arrest of the cell cycle in the G2/M phase. These phenomena triggered processes of apoptosis proven by activation of caspase 3 and externalization of phosphatidylserine and loss of cell integrity from 1.0 μM. The combination with BSO induced a marked increase in the apoptotic population. On the other hand, an improved cell proliferation effect was observed when combining SDQCu with a radiation dose of 2 Gy from 1.0 μM or with 6 Gy from 1.5 μM. Finally, studies in multicellular spheroids demonstrated that even though copper(II) complexes did not inhibit cell invasion in collagen gels up to 48 h of treatment at the higher concentrations, multicellular resistance outperformed several drugs currently used in cancer treatment. Overall, our results reveal an antitumor effect of both complexes in monolayer and multicellular spheroids and an improvement with the addition of BSO. However, only SDQCu was the best adjuvant of ionizing radiation treatment.

Nanopesticides in Agriculture: Benefits and Challenge in Agricultural Productivity, Toxicological Risks to Human Health and Environment

Nanopesticides are nanostructures with two to three dimensions between 1 to 200 nm, used to carry agrochemical ingredients (AcI). Because of their unique properties, the loading of AcI into nanoparticles offers benefits when compared to free pesticides. However, with the fast development of new engineered nanoparticles for pests' control, a new type of environmental waste is being produced. This paper describes the nanopesticides sources, the harmful environmental and health effects arising from pesticide exposure. The potential ameliorative impact of nanoparticles on agricultural productivity and ecosystem challenges are extensively discussed. Strategies for controlled release and stimuli-responsive systems for slow, sustained, and targeted AcI and genetic material delivery are reported. Special attention to different nanoparticles source, the environmental behavior of nanopesticides in the crop setting, and the most recent advancements and nanopesticides representative research from experimental results are revised. This review also addresses some issues and concerns in developing, formulating and toxicity pesticide products for environmentally friendly and sustainable agriculture.

Roles of ROS and cell cycle arrest in the genotoxicity induced by gold nanorod core/silver shell nanostructure

To understand the genotoxicity induced in the liver by silver nanoparticles (AgNPs) and silver ions, an engineered gold nanorod core/silver shell nanostructure (Au@Ag NR) and humanized hepatocyte HepaRG cells were used in this study. The involvement of oxidative stress and cell cycle arrest in the DNA and chromosome damage induced by 0.4-20 µg mL^-1 Au@Ag NR were investigated by comet assay, γ-H2AX assay and micronucleus test. Further, the distribution of Au@Ag NR was analyzed. Our results demonstrated that both Ag⁺ and Au@Ag NR led to DNA cleavage and chromosome damage (clastogenicity) in HepaRG cells and that the Au@Ag NR retained in the nucleus may further release Ag⁺, aggravating the damages, which are mainly caused by cell cycle arrest and ROS formation. The results reveal the correlation between the intracellular accumulation, Ag⁺ ion release and the potential genotoxicity of AgNPs.

Zinc and selenium combination treatment protected diabetes-induced testicular and epididymal damage in rat

Diabetes increases the possibility of germ cell damage, hypogonadism, and male infertility. Diabetic condition negatively impacts zinc (Zn) and selenium (Se) levels in the body. Zn and Se are among the most important trace elements involved in the regulation of redox reaction, antioxidants enzymes activities, and DNA expression in a germ cell. The present study aimed to elucidate the combined effects of Zn and Se treatment on diabetes-induced germ cell damage in male Sprague Dawley rats. Type 1 diabetes was induced by the single intraperitoneal (i.p.) injection of streptozotocin (55 mg/kg). Zn (3 mg/kg, i.p.) and Se (0.5 mg/kg, i.p.) were administered daily for 8 consecutive weeks. All the animals were provided with normal feed and water throughout the study. The effects on germ cell damage were evaluated by body weight, feed-water intake, organ weight, sperm count, motility, sperm head morphology, biochemical analysis, histology, immunohistochemistry, halo assay, germ cell comet assay, testes terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end-labeling (TUNEL) assay, sperm TUNEL assay, serum protein pattern analysis, and subcellular analysis using transmission electron microscopy. Further, the expressions of nuclear erythroid-derived related factor 2, catalase, glutathione peroxidase 4, and glutathione peroxidase 5 were carried out to ascertain the mechanism of protection. The present results demonstrated that 8 weeks combined treatment of Zn (3 mg/kg, i.p.) and Se (0.5 mg/kg, i.p.) reduced diabetes-induced germ cell damage. This study further highlighted that Zn and Se combination treatment might be a better strategy for the germ cell protection in diabetes and deserve further investigation.

Systems chemo-biology analysis of DNA damage response and cell cycle effects induced by coal exposure

Cell cycle alterations are among the principle hallmarks of cancer. Consequently, the study of cell cycle regulators has emerged as an important topic in cancer research, particularly in relation to environmental exposure. Particulate matter and coal dust around coal mines have the potential to induce cell cycle alterations. Therefore, in the present study, we performed chemical analyses to identify the main compounds present in two mineral coal samples from Colombian mines and performed systems chemo-biology analysis to elucidate the interactions between these chemical compounds and proteins associated with the cell cycle. Our results highlight the role of oxidative stress generated by the exposure to the residues of coal extraction, such as major inorganic oxides (MIOs), inorganic elements (IEs) and polycyclic aromatic hydrocarbons (PAH) on DNA damage and alterations in the progression of the cell cycle (blockage and/or delay), as well as structural dysfunction in several proteins. In particular, IEs such as Cr, Ni, and S and PAHs such as benzo[a]pyrene may have influential roles in the regulation of the cell cycle through DNA damage and oxidative stress. In this process, cyclins, cyclin-dependent kinases, zinc finger proteins such as TP53, and protein kinases may play a central role.

A new chemiluminescence method for the determination of 8-hydroxyguanine based on l-histidine bound nickel nanoparticles

A new chemiluminescence aptasensor for sensitive and efficient detection of 8-hydroxyguanine based on the synergistic interaction of Ni NPs@l-histidine@aptamer@MBs has been developed, and it has been applied in the real urine samples of cancer patients.

The role of the enzyme-modified comet assay in in vivo studies

The in vivo comet assay is an established genotoxicity test, with an OECD test guideline, but in its standard form it measures only DNA strand breaks. Including in the assay an additional step, in which the DNA is incubated with a lesion-specific enzyme, can provide important information about the nature of the DNA damage. Formamidopyrimidine DNA glycosylase, 8-oxoguanine DNA glycosylase or endonuclease III are commonly used in the in vitro genotoxicity test and in human biomonitoring to detect oxidised bases, but in vivo applications are rarer. A systematic literature search has identified a total of 60 papers that report such in vivo experiments, testing a variety of agents. In many cases, strand breaks were not seen, but significant levels of enzyme-sensitive sites were induced - indicating a mechanism of action involving oxidative stress. Compounds such as methyl methanesulfonate (MMS) or ethyl methanesulfonate (EMS) could be used as positive controls in both the standard and the enzyme-modified in vivo comet assays.

Evaluation of the genotoxic, DNA-protective and antioxidant profile of synthetic alkyl gallates and gallotannins using in vitro assays

New gallotanins, methyl 2,3,4,6-tetra-O-galloyl-α-D-glucoside (G₄Glc), methyl 2,3,4,6-tetra-O-galloyl-α-D-mannoside (G₄Man), and methyl 2,3,4-tri-O-galloyl-α-L-rhamnoside (G₃Rham), have been synthesized in order to study the protective effects of synthetic polyphenols that are structurally related with natural compounds. Apart from spectral analysis, examination of antioxidant ability and protective efficiency showed the differences among newly prepared compounds and commercial antioxidants - gallic acid (GA), methyl gallate (MG), and octyl gallate (OG) applying radical scavenging 1,1-diphenyl-2-picryl-hydrazyl (DPPH), reducing power and iron-chelating assays. The genotoxicity and DNA-protective potential of tested compounds on human peripheral blood mononuclear cells (PBMCs) were evaluated using the single-cell gel electrophoresis (comet assay) and DNA-topology assay. Experimental data revealed that gallotannins G₃Rham, G₄Man, and G₄Glc possess significant radical scavenging/antioxidant activities and manifest very low genotoxic effect on human PBMCs. Moreover, tested compounds considerably reduce the level of DNA damage induced by hydrogen peroxide or Fe²⁺-ions. The results imply that new synthetic gallotannins can be considered as nontoxic agents for subsequent design of new antioxidants with potential biomedical applications.

Melatonin-loaded lipid-core nanocapsules protect against lipid peroxidation caused by paraquat through increased SOD expression in Caenorhabditis elegans

BACKGROUND

Melatonin has been described in the literature as a potent antioxidant. However, melatonin presents variable, low bioavailability and a short half-life. The use of polymeric nanoparticulated systems has been proposed for controlled release. Thus, the purpose of this study was to investigate the action of melatonin-loaded lipid-core nanocapsules (Mel-LNC) in the antioxidant system of Caenorhabditis elegans, and the possible protective effect of this formulation against lipid peroxidation caused by paraquat (PQ).

METHODS

The suspensions were prepared by interfacial deposition of the polymer and were physiochemically characterized. C. elegans N2 wild type and transgenic worm CF1553, muls84 [sod-3p::gfp; rol6(su1006)] were obtained from the Caenorhabditis Genetics Center (CGC). The worms were divided into 5 groups: Control, PQ 0.5 mM, PQ 0.5 mM + Mel-LNC 10 μg/mL, PQ + unloaded lipid-core nanocapsules (LNC), and PQ + free melatonin (Mel) 10 μg/mL. The lipid peroxidation was assessed through thiobarbituric acid (TBARS) levels and the fluorescence levels of the transgenic worms expressing GFP were measured.

RESULTS

The LNC and Mel-LNC presented a bluish-white liquid, with pH values of 5.56 and 5.69, respectively. The zeta potential was - 6.4 ± 0.6 and - 5.2 ± 0.2, respectively. The mean particle diameter was 205 ± 4 nm and 203 ± 3 nm, respectively. The total melatonin content was 0.967 mg/ml. The TBARS levels were significantly higher in the PQ group when compared to the control group (p < 0.001). Mel-LNC reduced TBARS levels to similar levels found in the control group. Moreover, only Mel-LNC significantly enhanced the SOD-3 expression (p < 0.05). Mel-LNC was capable of protecting C. elegans from lipid peroxidation caused by PQ and this was not observed when free melatonin was used. Moreover, Mel-LNC increased the fluorescence intensity of the transgenic strain that encodes the antioxidant enzyme SOD-3, demonstrating a possible mechanism of protection from PQ-induced damage.

CONCLUSION

These findings demonstrated that melatonin, when associated with nanocapsules, had improved antioxidant properties and the protective activity against PQ-induced lipid peroxidation could be associated with the activation of antioxidant enzymes by Mel-LNC in C. elegans.

Neuroprotective Dipeptide Noopept Prevents DNA Damage in Mice with Modeled Prediabetes

In experiments on BALB/c mice, prediabetes was modeled by administration of streptozotocin in a dose of 130 mg/kg. DNA damage was assessed by the method of DNA comets. Noopept (0.5 mg/kg intraperitoneally) was administered for 14 days before and for 6, 13, or 14 days after streptozotocin administration. Despite moderate hyperglycemia and increased malondialdehyde level, the intensity of DNA damage in cells of the pancreas, liver, and kidneys significantly surpassed the control values. Noopept normalized these parameters due to its pronounced antigenotoxic effect. For both the damaging effect of streptozotocin and the normalizing effect of Noopept, DNA changes manifested mainly in terms of atypical DNA comets. Our findings confirm the role of DNA damage in the pathogenesis of diabetes. They indicate the possibility of pharmacological protection of pancreatic β cells with the neuroprotective drug and provide an important argument in favor of the hypothesis about the similarity of the mechanisms of formation of the resistance of neurons and β cells to the cytotoxic influences.

Dimeric NGF Mimetic Attenuates Hyperglycaemia and DNA Damage in Mice with Streptozotocin-Induced Early-Stage Diabetes

BACKGROUND

NGF deficiency is one of the reasons for reduced β-cells survival in diabetes. Our previous experiments revealed the ability of low-weight NGF mimetic, GK-2, to reduce hyperglycaemia in a model of advanced diabetes. The increase in DNA damage in advanced diabetes was repeatedly reported, while there were no data about DNA damage in the initial diabetes.

AIM

The study aimed to establish whether DNA damage occurs in initial diabetes and whether GK-2 is able to overcome the damage.

METHODS

The early-stage diabetes was modelled in Balb/c mice by streptozotocin (STZ) (130 mg/kg, i.p.). GK-2 was administered at a dose of 0.5 mg/kg, i.p., subchronically. The evaluation of DNA damage was performed using the alkaline comet assay; the percentage of DNA in the tail (%TDNA) and the percentage of the atypical DNA comets ("ghost cells") were determined.

RESULTS

STZ at this subthreshold dose produced a slight increase in glycemia and MDA. Meanwhile, pronounced DNA damage was observed, concerning mostly the percentage of "ghost cells" in the pancreas, the liver and kidneys. GK-2 attenuated the degree of hyperglycaemia and reduced the % of "ghost cells" and %TDNA in all the organs examined; this effect continued after discontinuation of the therapy.

CONCLUSION

Early-stage diabetes is accompanied by DNA damage, manifested by the increase of "ghost cells" percentage. The severity of these changes significantly exceeds the degree of hyperglycaemia and MDA accumulation. GK-2 exerts an antihyperglycaemic effect and attenuates the degree of DNA damage. Our results indicate that the comet assay is a highly informative method for search of antidiabetic medicines.

Proteomics Analysis of Tangeretin-Induced Apoptosis through Mitochondrial Dysfunction in Bladder Cancer Cells

Tangeretin is one of the most abundant compounds in citrus peel, and studies have shown that it possesses anti-oxidant and anti-cancer properties. However, no study has been conducted on bladder cancer cells. Bladder cancer has the second highest mortality rate among urological cancers and is the fifth most common malignancy in the world. Currently, combination chemotherapy is the most common approach by which to treat patients with bladder cancer, and thus identifying more effective chemotherapeutic agents that can be safely administered to patients is a very important research issue. Therefore, this study investigated whether tangeretin can induce apoptosis and identified the signaling pathways of tangeretin-induced apoptosis in human bladder cancer cells using two-dimensional gel electrophoresis (2DGE). The results of the study demonstrated that 60 μM tangeretin reduced the cell survival of a BFTC-905 bladder carcinoma cell line by 42%, and induced early and late apoptosis in the cells. In this study 2DGE proteomics technology identified 41 proteins that were differentially-expressed in tangeretin-treated cells, and subsequently LC–MS/MS analysis was performed to identify the proteins. Based on the functions of the differentially-expressed proteins, the results suggested that tangeretin caused mitochondrial dysfunction and further induced apoptosis in bladder cancer cells. Moreover, western blotting analysis demonstrated that tangeretin treatment disturbed calcium homeostasis in the mitochondria, triggered cytochrome C release, and activated caspase-3 and caspase-9, which led to apoptosis. In conclusion, our results showed that tangeretin-induced apoptosis in human bladder cancer cells is mediated by mitochondrial inactivation, suggesting that tangeretin has the potential to be developed as a new drug for the treatment of bladder cancer.

Can ursolic acid be beneficial against diabetes in rats?

Objective:

Diabetes mellitus, a heteregenous metabolic and chronic disease, is a growing health problem especially in developing countries. It is claimed that diabetes associated with increased formation of free radicals and decrease in antioxidant potential and also alterations in lipid profile and enzyme levels. Ursolic acid is commonly used in traditional Chinese medicine due to its beneficial effects. The aim of this study was to investigate the effects of ursolic acid on streptozotocin-induced diabetes in Wistar albino rats.

Methods:

DNA damage was evaluated in the blood and liver cells of rats by alkaline comet assay. The activities of antioxidant enzymes, oxidative stress parameters, biochemical parameters, hepatic enzyme levels and lipid profile parameters were also evaluated.

Results:

The results of this study demonstrate that diabetes caused genotoxic damage, changes in hepatic enzyme and lipid profile, biochemical and antioxidant enzyme activities and oxidative stress parameters in rats. Ursolic acid was found to be protective against diabetes induced effects in blood and liver samples of rats.

Conclusions:

According to our results, it seems that ursolic acid may be beneficial against diabetes and its adverse effects in rats.

Protective Effects of Ursolic Acid in the Kidneys of Diabetic Rats

Objectives

Diabetes, a heteregenous metabolic and chronic disease, is a growing health problem in most countries. It has been claimed that diabetes is associated with the increased formation of free radicals and decreased in antioxidant potential. Oxidative stress formed in diabetes may cause DNA damage in the tissues. Ursolic acid, a well-known pentacylic triterpene, is commonly used in traditional Chinese medicine due to its beneficial health effects such as antioxidant, anticancer, and antiulcer properties. The aim of this study was to investigate the effects of ursolic acid in the kidneys of Wistar albino rats with streptozotocin-induced diabetes.

Materials and Methods

DNA damage was evaluated in the kidney cells of rats using alkaline comet assays. Oxidative stress parameters such as CAT, SOD, GR, and GSH-Px enzyme activities and total GSH and MDA levels were also evaluated.

Results

Ursolic acid treatment was found to significantly decrease DNA damage, GR enzyme activities, and MDA levels, and significantly increase GSH levels and CAT, SOD and GSH-Px enzyme activities in diabetic rats.

Conclusion

According to our results, it seems that ursolic acid may be beneficial against diabetes-induced renal damage.

Single Cell Gel Electrophoresis for the Detection of Genomic Ribonucleotides

Single cell gel electrophoresis or comet assay enables the quantification of DNA damage such as single-strand or double-strand breaks on a single cell level. Here, we describe a variant of this method for the detection of ribonucleotides embedded in genomic DNA. Briefly, cells are embedded in agarose on a microscopic slide, lysed under high salt and alkaline conditions and then subjected to in situ treatment with E. coli RNase HII which nicks 5' to a ribonucleotide within the context of a DNA duplex thereby converting genomic ribonucleotides into strand breaks. After unwinding of genomic DNA using a highly alkaline buffer, electrophoresis under mild alkaline conditions is performed resulting in formation of comets due to migration of fragmented DNA toward the anode. Following SYBR Gold staining comets can be visualized by fluorescence microscopy. In this setting, the length and the intensity of comets formed reflect the level of genomic ribonucleotides present in a given cell.

Purported Interactions of Amyloid-β and Glucocorticoids in Cytotoxicity and Genotoxicity: Implications in Alzheimer's Disease

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by the presence of aggregates of the amyloid-β peptide (Aβ) that are believed to be neurotoxic. One of the purposed damaging mechanisms of Aβ is oxidative insult, which eventually could damage the cellular genome. Stress and associated increases in glucocorticoids (GCs) have been described as a risk factor for the development of AD, although the purported genotoxic effects of GCs have not been fully characterized. Therefore, it is possible to speculate about purported synergistic effects of GCs on the Aβ-driven genotoxic damage. This in vitro study addresses the single and combined cyto/genotoxic effects of Aβ and GCs in SH-SY5Y cells. Cytotoxicity was determined by the MTT assay, and the genotoxic effects were studied using the comet assay. A comet assay derivation allows for measuring the presence of the FPG-sensitive sites (mainly 8-oxoguanines) in the DNA, apart from the DNA strand breaks. Treatment with Aβ (10 μM, 72 h) induced cytotoxicity (35% decrease in cell viability) and DNA strand breaks, but had no significant effect on oxidative DNA damage (FPG sites). Corticosterone showed no effect on cell viability, genotoxicity, or reparation processes. Corticosterone was unable to neither reverse nor potentiate Aβ driven effects. The present results suggest the existence of alternative mechanisms for the Aβ driven damage, not involving oxidative damage of DNA. In addition, could be suggested that the interaction between Aβ and GCs in AD does not seem to involve DNA damage.

d-limonene ameliorates diabetes and its complications in streptozotocin-induced diabetic rats

It is known that diabetes causes some complications including alterations in lipid profile, hepatic enzyme levels but also it causes oxidative stress. Limonene, a major component of Citrus oils, has important health beneficial effects in lowering the level of oxidative stress due to its antioxidant activity. The aim of this study was to investigate the effects of D-limonene on streptozotocin (STZ)-induced diabetes in Wistar albino rats. For this purpose, DNA damage was evaluated by alkaline comet assay. Changes in the activities of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GSHPx) and the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), total glutathione (GSH), malondialdehyde (MDA), insulin, total bilirubin and BCA protein, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT), high density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol and triglyceride were also evaluated. D-limonene treatment was found to significantly decrease DNA damage, GR enzyme activities and MDA levels and significantly increase GSH levels and CAT, SOD and GSH-Px enzyme activities and altered lipid and liver enzyme parameters in diabetic rats. According to our results, it seems that D-limonene might have a role in the prevention of the complication of diabetes in rats.

Evaluation of imazethapyr-induced DNA oxidative damage by alkaline Endo III- and Fpg-modified single-cell gel electrophoresis assay in Hypsiboas pulchellus tadpoles (Anura, Hylidae)

Imazethapyr (IMZT) is a selective postemergent herbicide with residual action. Available data analyzing its effects in aquatic vertebrates are scarce. In previous studies, we demonstrated that IMZT induces lesions into the DNA of Hypsiboas pulchellus tadpoles using the single-cell gel electrophoresis (SCGE) assay as a biomarker for genotoxicity. Currently, this assay can be modified by including incubation with lesion-specific endonucleases, e.g., endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg), which detect oxidized pyrimidine and purine bases, respectively. The aim of this study was to evaluate the role of oxidative stress in the genotoxic damage in circulating blood cells of H. pulchellus tadpoles exposed to the IMZT-based Pivot H^® formulation (10.59% IMZT) at a concentration equivalent to 25% of the LC₅₀ (96h) value (0.39mg/L IMZT) during 48 and 96h. Our results demonstrate that the herbicide induces oxidative DNA damage on H. pulchellus tadpoles at purines bases but not at pyrimidines. Our findings represent the first evidence of oxidative damage caused by IMZT on anuran DNA using the alkaline restriction enzyme-modified SCGE assay.

Strong inhibition of the polyol pathway diverts glucose flux to protein glycation leading to rapid establishment of secondary complications in diabetes mellitus

BACKGROUND

Polyol pathway and protein glycation are implicated in establishing secondary complications in diabetes. Their relative contribution to the process needs to be evaluated. It is essential to understand why some aldose reductase inhibitors (ARIs) trials are successful while some have failed and to study their effect on protein glycation.

METHODS

Aldose reductase (AR) was assayed using xylose as substrate; protein glycation was evaluated using total and specific fluorescence, fructoseamine and protein bound carbonyl content (PCO) measurements. Long term studies were carried out on streptozotocin induced diabetic rats for evaluation of urine parameters, tissue fluorescence. Anti-cataract action was studied by lens culture studies.

RESULTS

Epalrestat, a commercial ARI was also found to possess potent glycation inhibitory action. Long term experiments revealed strong protein glycation with higher concentration of citronellol (ARI) demonstrating shift in glucose flux. Treatment with epalrestat and limonene revealed improved urine parameters and tissue fluorescence. Lens culture studies revealed cataract formation at higher inhibition of AR while no lens opacity was observed at lower citronellol concentration and with limonene and epalrestat.

CONCLUSION

Strong inhibition of AR shifts the glucose flux to protein glycation causing damage. ARIs possessing protein glycation inhibition are more useful in amelioration of secondary complications.

Evidence for DNA damage as a biological link between diabetes and cancer

Objective:

This review examines the evidence that: Diabetes is a state of DNA damage; pathophysiological factors in diabetes can cause DNA damage; DNA damage can cause mutations; and DNA mutation is linked to carcinogenesis.

Data Sources:

We retrieved information from the PubMed database up to January, 2014, using various search terms and their combinations including DNA damage, diabetes, cancer, high glucose, hyperglycemia, free fatty acids, palmitic acid, advanced glycation end products, mutation and carcinogenesis.

Study Selection:

We included data from peer-reviewed journals and a textbook printed in English on relationships between DNA damage and diabetes as well as pathophysiological factors in diabetes. Publications on relationships among DNA damage, mutagenesis, and carcinogenesis, were also reviewed. We organized this information into a conceptual framework to explain the possible causal relationship between DNA damage and carcinogenesis in diabetes.

Results:

There are a large amount of data supporting the view that DNA mutation is a typical feature in carcinogenesis. Patients with type 2 diabetes have increased production of reactive oxygen species, reduced levels of antioxidant capacity, and increased levels of DNA damage. The pathophysiological factors and metabolic milieu in diabetes can cause DNA damage such as DNA strand break and base modification (i.e., oxidation). Emerging experimental data suggest that signal pathways (i.e., Akt/tuberin) link diabetes to DNA damage. This collective evidence indicates that diabetes is a pathophysiological state of oxidative stress and DNA damage which can lead to various types of mutation to cause aberration in cells and thereby increased cancer risk.

Conclusions:

This review highlights the interrelationships amongst diabetes, DNA damage, DNA mutation and carcinogenesis, which suggests that DNA damage can be a biological link between diabetes and cancer.

Protective effects of melatonin-loaded lipid-core nanocapsules on paraquat-induced cytotoxicity and genotoxicity in a pulmonary cell line

Many acute poisonings lack effective and specific antidotes. Due to both intentional and accidental exposures, paraquat (PQ) causes thousands of deaths annually, especially by pulmonary fibrosis. Melatonin (Mel), when incorporated into lipid-core nanocapsules (Mel-LNC), has enhanced antioxidant properties. The effects of such a formulation have not yet been studied with respect to mitigation of PQ- induced cytotoxicity and DNA damage. Here, we have tested whether Mel-LNC can ameliorate PQ-induced toxicity in the A549 alveolar epithelial cell line. Physicochemical characterization of the formulations was performed. Cellular uptake was measured using nanocapsules marked with rhodamine B. Cell viability was determined by the MTT assay and DNA damage was assessed by the comet assay. The enzyme-modified comet assay with endonuclease III (Endo III) and formamidopyrimidine glycosylase (FPG) were used to investigate oxidative DNA damage. Incubation with culture medium for 24h did not alter the granulometric profile of Mel-LNC formulations. Following treatment (3 and 24h), red fluorescence was detected around the cell nucleus, indicating internalization of the formulation. Melatonin solution (Mel), Mel-LNC, and LNC did not have significant effects on cell viability or DNA damage. Pre-treatment with Mel-LNC enhanced cell viability and showed a remarkable reduction in % DNA in tail compared to the PQ group; this was not observed in cells pre-treated with Mel. PQ induces oxidative DNA damage detected with the enzyme-modified comet assay. Mel-LNC reduced this damage more effectively than did Mel. In summary, Mel-LNC is better than Mel at protecting A549 cells from the cytotoxic and genotoxic effects of PQ.

Effects of nicotine on the testicular toxicity of streptozotocin-induced diabetic rat

The aim of the present study is to investigate whether nicotine augmented the testicular toxicity and angiotensin converting enzyme inhibitor, enalapril, can ameliorate the effects in diabetic rat. Male Sprague Dawley rats were randomized into five groups: control, nicotine, diabetic, Diab + Nico, and Diab + Nico + Enal. Animals were made diabetic by single injection of streptozotocin (55 mg/kg/intraperitoneally). Nicotine dissolved in drinking water at a concentration of 100 µg/ml was given ad libitum and enalapril was given orally at a dose of 10 mg/kg/day for four consecutive weeks. After 4 weeks of treatment, animals were killed and biochemical parameters glucose, glycosylated hemoglobin, cotinine, and the testosterone levels were measured. Testicular toxicity was evaluated using sperm count, sperm comet assay, histology, and immunohistochemical staining of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxo-dG) and the proinflammatory markers (nuclear factor kappa B (NF-κB), cyclooxygenase (COX-2), and tissue necrotic factor alpha (TNF-α)) evaluated by western blotting. Results showed that nicotine did not alter the blood glucose and glycosylated hemoglobin level, significantly decreased the sperm count and increased the sperm DNA damage. These changes were accompanied by significant increases in the 8-oxo-dG, NF-κB, COX-2, and TNF-α expression. Furthermore, the intervention of enalapril in nicotine-treated diabetic rat attenuated the testicular damage and restored sperm count, sperm DNA damage, as well as reduced the expression of NF-κB, COX-2, and TNF-α. These findings clearly suggest that nicotine not only augmented the testicular toxicity in the diabetic rat but also increases the risk of germ cell toxicity effects that were attenuated by enalapril treatment.

Combusted but not smokeless tobacco products cause DNA damage in oral cavity cells

The aim of this work was to investigate genomic DNA damage in human oral cavity cells after exposure to different tobacco product preparations (TPPs). The oral carcinoma cell line 101A, gingival epithelial cells HGEC, and gingival fibroblasts HGF were exposed to TPM (total particulate matter from 3R4F cigarettes), ST/CAS (2S3 smokeless tobacco extract in complete artificial saliva), and NIC (nicotine). Treatments were for 24 h using TPM at its EC-50 doses, ST/CAS and NIC at doses with equi-nicotine units, and high doses for ST/CAS and NIC. Comet assays showed that TPM, but not ST/CAS or NIC, caused substantial DNA breaks in cells; only the high ST/CAS dose caused weak DNA damage. These results were confirmed by immunofluorescence for γ-H2AX protein. These data revealed that the combusted TPP caused substantial DNA damage in all cell types, whereas the two non-combusted TPPs exerted no or only minimal DNA damage. They support epidemiologic evidence on the relative risk associated with consumption of non-combusted versus combusted tobacco products, and help to understand potential genotoxic effects of such products on oral cavity cells.

Contribution of environment and genetics to pancreatic cancer susceptibility

Several risk factors have been identified as potential contributors to pancreatic cancer development, including environmental and lifestyle factors, such as smoking, drinking and diet, and medical conditions such as diabetes and pancreatitis, all of which generate oxidative stress and DNA damage. Oxidative stress status can be modified by environmental factors and also by an individual's unique genetic makeup. Here we examined the contribution of environment and genetics to an individual's level of oxidative stress, DNA damage and susceptibility to pancreatic cancer in a pilot study using three groups of subjects: a newly diagnosed pancreatic cancer group, a healthy genetically-unrelated control group living with the case subject, and a healthy genetically-related control group which does not reside with the subject. Oxidative stress and DNA damage was evaluated by measuring total antioxidant capacity, direct and oxidative DNA damage by Comet assay, and malondialdehyde levels. Direct DNA damage was significantly elevated in pancreatic cancer patients (age and sex adjusted mean ± standard error: 1.00 ± 0.05) versus both healthy unrelated and related controls (0.70 ± 0.06, p<0.001 and 0.82 ± 0.07, p = 0.046, respectively). Analysis of 22 selected SNPs in oxidative stress and DNA damage genes revealed that CYP2A6 L160H was associated with pancreatic cancer. In addition, DNA damage was found to be associated with TNFA -308G>A and ERCC4 R415Q polymorphisms. These results suggest that measurement of DNA damage, as well as select SNPs, may provide an important screening tool to identify individuals at risk for development of pancreatic cancer.

Proteomic analysis of aorta and protective effects of grape seed procyanidin B2 in db/db mice reveal a critical role of milk fat globule epidermal growth factor-8 in diabetic arterial damage

Background

Atherosclerosis is one of the major complications of type 2 diabetic patients (T2DM), leading to morbidity and mortality. Grape seed procyanidin B2 (GSPB2) has demonstrated protective effect against atherosclerosis, which is believed to be, at least in part, a result of its antioxidative effects. The aim of this study is to identify the target protein of GSPB2 responsible for the protective effect against atherosclerosis in patients with DM.

Methods and Results

GSPB2 (30 mg/kg body weight/day) were administrated to db/db mice for 10 weeks. Proteomics of the aorta extracts by iTRAQ analysis was obtained from db/db mice. The results showed that expression of 557 proteins were either up- or down-regulated in the aorta of diabetic mice. Among those proteins, 139 proteins were normalized by GSPB2 to the levels comparable to those in control mice. Among the proteins regulated by GSPB2, the milk fat globule epidermal growth factor-8 (MFG-E8) was found to be increased in serum level in T2DM patients; the serum level of MFG-E8 was positively correlated with carotid-femoral pulse wave velocity (CF-PWV). Inhibition of MFG-E8 by RNA interference significantly suppressed whereas exogenous recombinant MFG-E8 administration exacerbated atherogenesis the db/db mice. To gain more insights into the mechanism of action of MFG-E8, we investigated the effects of MFG-E8 on the signal pathway involving the extracellular signal-regulated kinase (ERK) and monocyte chemoattractant protein-1 (MCP-1). Treatment with recombinant MFG-E8 led to increased whereas inhibition of MFG-E8 to decreased expression of MCP-1 and phosphorylation of ERK1/2.

Conclusion

Our data suggests that MFG-E8 plays an important role in atherogenesis in diabetes through both ERK and MCP-1 signaling pathways. GSPB2, a well-studied antioxidant, significantly inhibited the arterial wall changes favoring atherogenesis in db/db mice by down-regulating MFG-E8 expression in aorta and its serum level. Measuring MFG-E8 serum level could be a useful clinical surrogate prognosticating atherogenesis in DM patients.