Oxidative stress and inflammatory markers in streptozotocin-induced acute and subacute toxicity response.

Streptozotocin (STZ) is used as a diabetes-inducing agent in experimental animal studies. However, it is known that STZ-induced diabetic animals show significant increases in oxidative stress parameters and neurodegeneration besides their blood glucose level. In this study, the acute and subacute toxic effects of STZ on the liver, sciatic nerve, and brain tissues were investigated in vivo rat model. Sprague-Dawley rats were divided into two groups; while 50 mg/kg STZ was administered ip to the STZ group, only saline was administered to the control group. After STZ administration, three units (100 U/mL) of subcutaneous insulin glargine were applied daily to prevent the formation of diabetes. At 24 h, 1,2, and 4 weeks after applications, rats from each group were sacrificed and tissues were removed under anesthesia. At the end of the study, compared to the control, a significant decrease in SOD and GST activity and an increase in lipid peroxidation were detected in the liver and sciatic tissues of rats in the STZ-treated group in the first 24h. Considering the TUNEL, NFκB, and NOS2 expressions, it was noted that while the effects of STZ on the liver were observed in the acute stage (24h), it had subacute effects on the brain. When apoptosis-related gene expression (Bcl-2, Bax, CASP3, CASP8, CASP9, TNF-α) and immunohistochemistry were evaluated, the apoptotic effect of STZ was observed mostly in sciatic nerve tissues. Within the scope of the study, it was revealed that STZ did not only show selective toxicity to pancreatic ß cells but also very toxic to other tissues and organs.

Bacterial metagenome analysis of Mytilus galloprovincialis collected from Istanbul and Izmir coastal stations of Turkey.

Mytilus galloprovincialis is a marine mollusk belonging to the Bivalvia class. It has been distributed largely in Turkish shores and worldwide aquatic environments. Besides being known as an environmental pollution indicator, it is highly consumed as a food and has a high economic value. Due to their nutritional mechanisms by filtering water, they are affected by pollution in seawater and mussels can host-microbial diversity of environmental origin as well as pathogenic bacteria. Therefore, in this study, bacterial species found in Mediterranean mussels collected from the coastal stations of Istanbul [Rumeli Kavagi (RK), Kucukcekmece (KC)], and Izmir [(Foca (MF), Urla (MU)] were investigated and compared with microbiological and metagenomic analyses. According to microbiological analysis results, 34 mussel-associated Enterobacteriaceae and Vibrionaceae family members were identified. As a result of the culture-independent metagenomic analysis, taxonomic groups for each station were identified and compared based on Operational Taxonomic Unit data. For all stations, the most abundant bacterial genera were the unclassified bacterial genera. The total number of mussel-related total richness identified in all groups was 4889 (RK = 1605; KC = 1930; MF = 1508; and MU = 1125). According to the metagenomic data obtained in this study, different relative amounts of Lachnospiraceae and Bacteroidetes taxa groups were reported for all stations. The pathogenic bacterial genera identified by metagenomic analyses which may be significant for the public health are Arcobacter, Clostridium, Aeromonas, Vibrio, Escherichia_Shigella, Klebsiella, Campylobacter, Helicobacter, Pseudomonas, Morganella, Serratia, Corynebacterium, Enterococcus, Staphylococcus, Yersinia, Mycoplasma, Brucellaceae_unclassified, Pantoea, and Proteus.

Mid-dose losartan mitigates diabetes-induced hepatic damage by regulating iNOS, eNOS, VEGF, and NF-κB expressions

Background/aim: Losartan, an antihypertensive drug, is highly preferred in patients with diabetes mellitus (DM) and hypertension because of its retarding effect on diabetic nephropathy. In this study, we investigated the potential therapeutic effect of different doses of losartan on hepatic damage in a streptozotocin (STZ, 50 mg/kg)-induced DM model in rats. Materials and methods: In this study, five different groups were formed: control, DM, low-dose losartan (5 mg/kg), mid-dose losartan (20 mg/kg), and high-dose losartan (80 mg/kg). Liver tissues of experimental groups were evaluated immunohistochemically for TUNEL, iNOS, eNOS, VEGF, and NF-κB pathways. In addition to immunohistochemical analysis, analyses of SOD and MDA, which are oxidative stress markers, were also performed and the results were evaluated together. Results: When biochemical and immunohistochemical findings were evaluated together, it was found that the results obtained from the mid-dose losartan group were closer to those of the control than the other groups. Conclusion: This study indicated that mid-dose losartan administration may have a therapeutic effect by inhibiting apoptosis and regulating iNOS, eNOS, VEGF, and NF-κB protein expressions in DM-induced hepatic damage.

Fluvastatin attenuates doxorubicin-induced testicular toxicity in rats by reducing oxidative stress and regulating the blood-testis barrier via mTOR signaling pathway.

Doxorubicin (DOX) is an anthracycline derivative antibiotic that still frequently used in the treatment of solid tumors and hematological malignancies. The clinical use of DOX is largely restricted due to acute and chronic renal, cardiac, hematological, and testicular toxicities. Previous studies have indicated that oxidative stress, lipid peroxidation, and apoptosis in germ cells are the main factors in DOX-induced testicular toxicity, but the entire molecular mechanisms that responsible for DOX-induced testicular damage are not yet fully understood. Fluvastatin is a cholesterol-lowering agent that acts by inhibiting hydroxylmethyl glutaryl coenzyme A, the key enzyme for cholesterol biosynthesis. In addition to its cholesterol-lowering effect, fluvastatin showed an antioxidant effect by cleaning hydroxyl and superoxide radicals and this drug could have a protective effect by acting on the mammalian target of rapamycin (mTOR) signal pathway in testicular damage caused by obesity. This study aimed to investigate the possible protective and therapeutic effects of fluvastatin on the DOX-induced testicular toxicity model by histochemical, immunohistochemical, biochemical, and real-time polymerase chain reaction analyses. The present study indicates that fluvastatin may have a protective and therapeutic effect by removing reactive oxygen species and by regulating the mTOR, connexin 43, and matrix metalloproteinase 9 protein and messenger ribonucleic acid expressions, which play an important role in regulating the blood-testis barrier. On the other hand, the use of fluvastatin as a protective/prophylactic agent was found to be more effective than the use of this drug for treatment. In light of this information, fluvastatin may be a candidate agent that can be used to prevent testicular toxicity observed in men receiving DOX treatment.

LuxCDE-luxAB-based promoter reporter system to monitor the Yersinia enterocolitica O:3 gene expression in vivo.

It is crucial to understand the in vitro and in vivo regulation of the virulence factor genes of bacterial pathogens. In this study, we describe the construction of a versatile reporter system for Yersinia enterocolitica serotype O:3 (YeO3) based on the luxCDABE operon. In strain YeO3-luxCDE we integrated the luciferase substrate biosynthetic genes, luxCDE, into the genome of the bacterium so that the substrate is constitutively produced. The luxAB genes that encode the luciferase enzyme were cloned into a suicide vector to allow cloning of any promoter-containing fragment upstream the genes. When the obtained suicide-construct is mobilized into YeO3-luxCDE bacteria, it integrates into the recipient genome via homologous recombination between the cloned promoter fragment and the genomic promoter sequence and thereby generates a single-copy and stable promoter reporter. Lipopolysaccharide (LPS) O-antigen (O-ag) and outer core hexasaccharide (OC) of YeO3 are virulence factors necessary to colonization of the intestine and establishment of infection. To monitor the activities of the OC and O-ag gene cluster promoters we constructed the reporter strains YeO3-Poc::luxAB and YeO3-Pop1::luxAB, respectively. In vitro, at 37°C both promoter activities were highest during logarithmic growth and decreased when the bacteria entered stationary growth phase. At 22°C the OC gene cluster promoter activity increased during the late logarithmic phase. Both promoters were more active in late stationary phase. To monitor the promoter activities in vivo, mice were infected intragastrically and the reporter activities monitored by the IVIS technology. The mouse experiments revealed that both LPS promoters were well expressed in vivo and could be detected by IVIS, mainly from the intestinal region of orally infected mice.

Multi-Biomarker Responses After Exposure to Pollution in the Mediterranean Mussels (Mytilus galloprovincialis L.) in the Aegean Coast of Turkey.

In this study, sublethal effects on the Mediterranean mussels (Mytilus galloprovincialis L.) collected from the Aegean coast of Turkey were determined. Enzymes such as glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and acetylcholinesterase (AChE), metallothionein (MT) mRNA expressions, thiobarbituric acid reactive substances (TBARS) contents, determination of 14 heavy metals and micronucleus frequency were selected as multibiomarkers. Results show that heavy metals and an increase in the level of MT gene expression have been determined in tissues of mussels collected from all stations. The GST, SOD and CAT enzymes were increased in mussels of Aliaga and Old Foca, compared to the mussels of Urla, while it was showed inhibition at AChE levels. Extensive LP is determined on mussels of Aliaga. It was determined that mussels in Aliaga region have exposed more oxidative stress than Old Foca and Urla. These biomarkers were carried out for the first time in these stations to assess environmental quality.

High throughput characterization of adult stem cells engineered for delivery of therapeutic factors for neuroprotective strategies.

Mesenchymal stem cells (MSCs) derived from bone marrow are a powerful cellular resource and have been used in numerous studies as potential candidates to develop strategies for treating a variety of diseases. The purpose of this study was to develop and characterize MSCs as cellular vehicles engineered for delivery of therapeutic factors as part of a neuroprotective strategy for rescuing the damaged or diseased nervous system. In this study we used mouse MSCs that were genetically modified using lentiviral vectors, which encoded brain-derived neurotrophic factor (BDNF) or glial cell-derived neurotrophic factor (GDNF), together with green fluorescent protein (GFP). Before proceeding with in vivo transplant studies it was important to characterize the engineered cells to determine whether or not the genetic modification altered aspects of normal cell behavior. Different culture substrates were examined for their ability to support cell adhesion, proliferation, survival, and cell migration of the four subpopulations of engineered MSCs. High content screening (HCS) was conducted and image analysis performed. Substrates examined included: poly-L-lysine, fibronectin, collagen type I, laminin, entactin-collagen IV-laminin (ECL). Ki67 immunolabeling was used to investigate cell proliferation and Propidium Iodide staining was used to investigate cell viability. Time-lapse imaging was conducted using a transmitted light/environmental chamber system on the high content screening system. Our results demonstrated that the different subpopulations of the genetically modified MSCs displayed similar behaviors that were in general comparable to that of the original, non-modified MSCs. The influence of different culture substrates on cell growth and cell migration was not dramatically different between groups comparing the different MSC subtypes, as well as culture substrates. This study provides an experimental strategy to rapidly characterize engineered stem cells and their behaviors before their application in long-term in vivo transplant studies for nervous system rescue and repair.

Induction of oxidative stress and histological changes in liver by subacute doses of butyl cyclohexyl phthalate.

Phthalates are esters of phthalic acid and are mainly used as plasticizers in a wide variety of products and applications. There is no information on butyl cyclohexyl phthalate (BCP) toxicity. This study was performed to evaluate the histopathological effects and to determine oxidative stress inducing potential in liver by subacute exposure of BCP. The animals of the treatment groups were orally administered 100, 200, and 400 mg/kg/day BCP for 5 consecutive days per week during 28 days. As a result, no significant changes were observed in body weight gains, and absolute and relative liver weights of liver of BCP treated mice, when compared with control group. Although the degree of lipid peroxidation in the liver tissue of all BCP exposure groups were significantly higher than those of the control (p < 0.01), SOD and CAT activities in liver tissue of mice of 200 and 400 mg/kg exposure groups were significantly lower than those of the controls (p < 0.01). Moreover, BCP caused dose-dependent histological changes in the liver of mice such as congestions in vena centralis, an enlargement of the sinusoids, degeneration in hepatocytes, vacuole formations and presence of lipid droplets in hepatocytes, eosinophilic cytoplasm. While iNOS immunoreactivity was increased in all treatment groups, Type IV collagen and Connexin 43 immunoreactivities were decreased in all treatment groups compared with the control group. Significant decrease was observed in the number of TUNEL-positive liver cells of BCP treated mice. These results suggested that BCP exposure induces oxidative stress in liver and exposure of BCP during long time period could lead to hepatocarcinogenesis.

Effects of restraint stress and nitric oxide synthase inhibition on learning and strategy preference in young adult male rats.

OBJECTIVE: The aim of this study was to investigate the effects of restraint stress and nitric oxide synthase (NOS) inhibition by NωNitro-L-Arginine (LNA) on learning and strategy preference. MATERIAL AND METHODS: Rats were randomly divided into four groups (Saline, Saline+Stress, LNA, LNA+Stress). Stress was applied for one hour in glass cylinders during 13 days. One hour after this stress application, water maze experiments were started. Injections (saline 1 ml/kg or 50 mg/kg LNA) were given 10 minutes before each experiment. The platform was kept visible or hidden (on the 4(th), 8(th), 12(th) days) at the same position. On the 13(th) day the platform was located on the opposite quadrant. RESULTS: Saline groups exhibited significantly better performances (F(1.31)=174.038 p<0.05) at the beginning compared to the NOS inhibited groups. For initial hidden platform days; stress was determined as an impairment factor (F(1.31)=5.190 p=0.012). At the end, acquisition occurred on both visible and hidden platform days for all groups. There was no significant strategy preference difference between the groups.Development of the stress and NOS inhibition impairments were seen, particularly at different periods of the acquisition. CONCLUSION: NOS inhibition did not worsen restraint stress-induced learning impairments in rats. Lack of effect may be explained by the antidepressive consequences of NOS inhibition.