Sevim Tunali

Synthesis, characterization and antidiabetic properties of N1-2,4-dihydroxybenzylidene-N4-2-hydroxybenzylidene-S-methyl-thiosemicarbazidato-oxovanadium(IV)

A new oxovanadium(IV) chelate [VOL] (L: N(1)-2,4-dihydroxybenzylidene-N(4)-2-hydroxybenzylidene-S-methyl-thiosemicarbazidato) was synthesized and characterized by elemental analysis, conductivity and magnetic measurements, UV-vis, IR, EPR spectroscopy and mass spectrometry. The biochemical and immunohistochemical effects of the administration of the vanadium complex (VOL) into the pancreas of normal and streptozotocin-induced diabetic rats were profoundly investigated. The animals were randomly divided into four groups. Group I: control (intact) animals. Group II: control animals administered with VOL. Group III: STZ-induced diabetic animals. Group IV: STZ-induced diabetic animals administered with VOL. VOL was given to some of the experimental animals by gavage at a dose of 0.2mM/kg every day for 12 days. Blood samples were collected from animals, on 0 and 1, 6 and 12 days after STZ injection. On day 12, the pancreatic tissues were taken from the animals. The tissue sections were labelled with streptavidin biotin peroxidase technique for insulin. In the diabetic group, the blood glucose levels, aspartate and alanine transaminases, alkaline phosphatase activities were increased. But, in the diabetic+VOL groups, the blood glucose levels, aspartate and alanine transaminases, alkaline phosphatase activities were reduced. In the diabetic group, a decrease in the pancreatic glutathione levels, glutathione peroxidase and superoxide dismutase activities and an increase in the pancreatic lipid peroxidation level and catalase activities were observed. The administration of VOL to the diabetic rats reversed this diabetic effect due to its insulinomimetic effects. According to the immunohistochemical and biochemical results obtained, it was concluded that VOL can regenerate B cells of the pancreas in experimental diabetes and has an antidiabetic and protective effects on the pancreas.

Influence of combined antioxidants against cadmium induced testicular damage.

Acute effects of cadmium (Cd) and combined antioxidants were evaluated in Sprague-Dawley rat testes. The rats were subdivided into four groups. Cadmium chloride (2mg/kgday) injected intraperitoneally during 8 days. Vitamin C (250mg/kgday), vitamin E (250mg/kgday) and sodium selenate (0.25mg/kgday) were pretreated by gavage in both of control and cadmium injected rats. Testis lipid peroxidation and glutathione levels were determined by spectrophotometrically. In Cd treated rats, lipid peroxidation levels were increased and glutathione levels were decreased and combined antioxidants treatment was effective in preventing of lipid peroxidation and normalizing glutathione. In Cd treated animals, the degenerative changes were observed, but not observed in the administrated rats with Cd and antioxidants under the light microscope. Proliferating cell nuclear antigen, metallothionein and caspase-3 activities were evaluated by immunohistochemically. Proliferation activity was not seen in the spermatogonial cells of cadmium treated testis. Treatment with antioxidants in cadmium administrated testis leads to pronounced increase in proliferation activity. Cytoplasmic caspase-3 activity was determined in the spermatogenic cells but not spermatogonia in treatment of antioxidants with Cd. In control and treated with antioxidants animals, metallothionein expressions were localized in the cells of seminiferous tubules, although the expression only was observed in the interstitial cells of cadmium treated rats. Results demonstrated beneficial effects of combined vitamin C, vitamin E and selenium treatment in Cd toxicity.

Effects of vanadyl sulfate on liver of streptozotocin-induced diabetic rats

The aim of this study was to investigate the microscopic and biochemical effects of vanadyl sulfate on liver tissue of normal and streptozotocin (65 mg/kg) diabetic rats. Vanadyl sulfate was administered by gavage at a dose of 100 mg/kg. Degenerative changes were observed in diabetic animals by light and transmission electron microscopes. Although there were individual differences in diabetic animals to which vanadium was given, some reduction of degenerative changes were detected. After 60 d of treatment, serum aspartate and alanine transaminase, alkaline phosphatase, blood glucose levels, liver lipid peroxidation, and nonenzymatic glycosylation significantly increased, but liver glutathione levels significantly decreased in the diabetic group. On the other hand, treatment with vanadyl sulfate reversed these effects. As a result, it might be concluded that vanadyl sulfate has a protective effect on damage of liver of streptozotocin-induced diabetic rats.

The potential role of combined anti-oxidants against cadmium toxicity on liver of rats.

Cadmium (Cd), a widely distributed toxic trace metal, has been shown to accumulate in liver after long- and short-term exposure. Cd (2mg/kg/day CdCl2) was intraperitoneally given to rats for eight days. Vitamin C (250mg/kg/day) + vitamin E (250mg/kg/day) + sodium selenate (0.25 mg/kg/day) were given to rats by oral means. The animals were treated by anti-oxidants one hour prior to treatment with Cd every day. The degenerative changes were observed in the groups given only Cd and anti-oxidants + Cd. Metallothionein (MT) immunoreactivity increased in cytoplasm of hepatocytes of the rats given Cd when compared with controls. In a number of cells with Cd and anti-oxidants treatment, immunoreactivity increase was more than in the group given Cd only and nuclear MT expression was also detected. Cell proliferation was assessed with proliferating cell nuclear antigen (PCNA) immunohistochemistry. PCNA expressions increased in all groups more than in the controls. Anti-oxidants treatment increased cell proliferation. In the animals administered with Cd, an increase in serum aspartate (AST) and alanine (ALT) aminotransferases, liver glutathione (GSH) and lipid peroxidation (LPO) levels were observed. On the other hand, in the rats treated with anti-oxidants and Cd, serum AST and ALT, liver glutathione and LPO levels decreased. As a result, these results suggest that combined anti-oxidants treatment might be useful in protection of liver against Cd toxicity. Toxicology and Industrial Health 2007; 23: 393—401.

Vanadyl sulfate administration protects the streptozotocin-induced oxidative damage to brain tissue in rats.

Diabetes mellitus manifests itself in a wide variety of complications and the symptoms of the disease are multifactorial. The present study was carried out to investigate the effects of vanadyl sulfate on biochemical parameters, enzyme activities and brain lipid peroxidation, glutathione and nonenzymatic glycosylation of normal- and streptozotocin-diabetic rats. Streptozotocin (STZ) was administered as a single dose (65 mg/kg) to induce diabetes. A dose of 100 mg/kg vanadyl sulfate was orally administered daily to STZ-diabetic and normal rats, separately until the end of the experiment, at day 60. In STZ-diabetic group, blood glucose, serum sialic and uric acid levels, serum catalase (CAT) and lactate dehydrogenase (LDH) activities, brain lipid peroxidation (LPO) and nonenzymatic glycosylation (NEG) increased, while brain glutathione (GSH) level and body weight decreased. In the diabetic group given vanadyl sulfate, blood glucose, serum sialic and uric acid levels, serum CAT and LDH activities and brain LPO and NEG levels decreased, but brain GSH and body weight increased.The present study showed that vanadyl sulfate exerted antioxidant effects and consequently may prevent brain damage caused by streptozotocin-induced diabetes.

Effects of vanadyl sulfate on kidney in experimental diabetes

The aim of this work was to investigate the biochemical and histological effects of vanadyl sulfate on blood glucose, urea, and creatinine in serum and nonenzymatic glycosylation and glutathione levels in kidney tissue of normal and streptozotocin (65 mg/kg) diabetic rats. Vanadyl sulfate was administered by gavage at a dose of 100 mg/kg. After 60 d of treatment, serum urea, creatinine, and blood glucose levels significantly increased in the diabetic group but not so in the vanadyl sulfate, which showed significantly reduced serum urea and blood glucose levels and a nonsignificant reduction of serum creatinine levels. Nonenzymatic glycosylation was increased and the glutathione level was decreased in the kidney tissue of diabetic rats. Treatment with vanadyl sulfate reversed these effects. Degenerative changes were detected in diabetic animals by electron and light microscopy. Although there are individual differences in diabetic animals given vanadium, some reduction of degenerative changes were observed.

Effects of vitamin U (S-methyl methionine sulphonium chloride) on valproic acid induced liver injury in rats.

In this study, we aimed to investigate the effects of vitamin U (Vit U) on valproic acid (VPA)-induced liver damage. Female Sprague Dawley rats were randomly divided into four groups. Group I was intact control animals. Group II was control rats given Vit U (50 mg/kg/day) for fifteen days. Group III was given only VPA (500 mg/kg/day) for fifteen days. Group IV was given VPA+Vit U (in same dose and time). Vit U was given to rats by gavage and VPA was given intraperitoneally. On the 16th day of experiment, all the animals were fasted overnight and then sacrificed under ether anesthesia. Liver tissue was taken from animals, homogenized in 0.9% saline to make up to 10% homogenate. Liver aspartate and alanine transaminases, alkaline phosphatase, lactate dehydrogenase, myeloperoxidase, sorbitol dehydrogenase, glutamate dehydrogenase and xanthine oxidase activities and lipid peroxidation levels were increased and paraoxonase activity and glutathione levels were decreased in VPA group. Treatment with Vit U reversed these effects. These results demonstrated that administration of Vit U is a potentially beneficial agent to reduce the liver damage in VPA induced hepatotoxicity, probably by decreasing oxidative stress.

Ameliorative effect of vanadium on oxidative stress in stomach tissue of diabetic rats

Between their broad spectrum of action, vanadium compounds are shown to have insulin mimetic/enhancing effects. Increasing evidence in experimental and clinical studies suggests that oxidative stress plays a major role in the pathogenesis of diabetes and on the onset of diabetic complications. Thus, preventive therapy can alleviate the possible side effects of the disease. The aim of the present study was to investigate the effect of vanadyl sulfate supplementation on the antioxidant system in the stomach tissue of diabetic rats. Male Swiss albino rats were randomly divided into 4 groups: control; control+vanadyl sulfate; diabetic; diabetic+vanadyl sulfate. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ; 65 mg/kg body weight). Vanadyl sulfate (100 mg/kg body weight) was given daily by gavage for 60 days. At the last day of the experiment, stomach tissues were taken and homogenized to make a 10% (w/v) homogenate. Catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), myeloperoxidase (MPO), carbonic anhydrase (CA), glucose-6-phosphate dehydrogenase (G6PD) and lactate dehydrogenase (LDH) activities were determined in the stomach tissue. CAT, SOD, GR, GPx, GST, CA, G6PD and LDH activities were increased in diabetic rats when compared to normal rats. Vanadium treatment significantly reduced the elevated activities of GR, GPx, GST compared with the diabetic group whereas the decreases in CAT, SOD, CA, G6PD and LDH activities were insignificant. No significant change was seen for MPO activity between the groups. It was concluded that vanadium could be used for its ameliorative effect against oxidative stress in diabetes.

Edaravone ameliorates the adverse effects of valproic acid toxicity in small intestine

Valproic acid (VPA) is a drug used for the treatment of epilepsy, bipolar psychiatric disorders, and migraine. Previous studies have reported an increased generation of reactive oxygen species and oxidative stress in the toxic mechanism of VPA. Edaravone, a free radical scavenger for clinical use, can quench free radical reaction by trapping a variety of free radical species. In this study, effect of edaravone on some small intestine biochemical parameters in VPA-induced toxicity was investigated. Thirty seven Sprague Dawley female rats were randomly divided into four groups. The groups include control group, edaravone (30 mg–1 kg–1 day–1) given group, VPA (0.5 g–1 kg–1 day–1) given group, VPA + edaravone (in same dose) given group. Edaravone and VPA were given intraperitoneally for 7 days. Biochemical parameters such as malondialdehyde, as an index of lipid peroxidation(LPO), sialic acid (SA), glutathione levels and glutathione peroxidase, glutathione-S-transferase, superoxide dismutase, catalase, myeloperoxidase, alkaline phosphatase (ALP), and tissue factor (TF) activities were determined in small intestine samples by colorimetric methods. Decreased small intestine antioxidant enzyme activities, increased LPO and SA levels, and increased activities of ALP and TF were detected in the VPA group. Based on our results edaravone may be suggested to reverse the oxidative stress and inflammation due to VPA-induced small intestine toxicity.

Investigation of the Effects of Edaravone on Valproic Acid Induced Tissue Damage in Pancreas

Valproic acid (VPA), an effective antiepileptic and anticonvulsant drug, has some toxic side effects due to causing elevated oxidant production. The aim of this study is to investigate the effects of edaravone, a potent free radical scavenger on VPA induced toxicity and tissue damage by biochemical and histological examinations on pancreas. Female Sprague Dawley rats were divided into four groups as follows; control, edaravone, VPA, VPA+edaravon. VPA and edaravone were injected intraperitonally for seven days. Total protein, lipid peroxidation (LPO), sialic acid (SA) and glutathione (GSH) levels and alkaline phosphatase (ALP), tissue factor (TF), superoxide dismutase (SOD), glutathione-S-transferase (GST), catalase (CAT), glutathione peroxidase (GPx) and myeloperoxidase (MPO) activities were determined in pancreas homogenates. In VPA given group, LPO and SA levels, and ALP, TF, MPO activities significantly increased and GST, CAT, GPx activities significantly decreased compared to control group. A marked morphological damage was detected in the VPA group. Ameliorative effects of edaravone were observed in SA, TF, CAT, GPx parameters and histological examination in the VPA group. Therefore, edaravone may be effective in moderation and/or reduction of toxic effects of VPA on pancreas.