Protective role of zinc in liver damage in experimental diabetes demonstrated via different biochemical parameters

Diabetes mellitus is a serious worldwide metabolic disease, which is accompanied by hyperglycaemia and affects all organs and body system. Zinc (Zn) is a basic cofactor for many enzymes, which also plays an important role in stabilising the structure of insulin. Liver is the most important target organ after pancreas in diabetic complications. In this study, we aimed to investigate the protective role of Zn in liver damage in streptozotocin (STZ)‐induced diabetes mellitus. There are four experimental groups of female Swiss albino rats: group I: control; group II: control + ZnSO₄; group III: STZ‐induced diabetic animals and group IV: STZ‐diabetic + ZnSO₄. To induce diabetes, STZ was injected intraperitoneally (65 mg/kg). ZnSO₄ (100 mg/kg) was given daily to groups II and IV by gavage for 60 days. At the end of the experiment, rats were killed under anaesthesia and liver tissues were collected. In the diabetic group, hexose, hexosamine, fucose, sialic acid levels, arginase, adenosine deaminase, tissue factor activities and protein carbonyl levels increased, whereas catalase, superoxide dismutase, glutathione‐S‐transferase, glutathione peroxidase, glutathione reductase and Na⁺/K⁺‐ATPase activities decreased. The administration of Zn to the diabetic group reversed all the negative effects/activities. According to these results, we can suggest that Zn has a protective role against STZ‐induced diabetic liver damage.     

玉米叶蝉缨翅缨小蜂Anagrus dmitrievi(膜翅目,缨小蜂科)DNA条形码研究

[目的]玉米叶蝉缨翅缨小蜂Anagrus dmitrievi Triapitsyn&Hu是玉米三点斑叶蝉Zyginidia eremita Zachvatkin卵期的重要寄生性天敌,在玉米三点斑叶蝉生物防治中具有广阔的应用前景.由于该寄生蜂个体微小,通过传统昆虫分类方法难以将其与同类卵寄生蜂准确分类.因此,本研究旨在为玉米叶蝉缨翅缨小蜂的快速准确鉴定提供技术支持.[方法]在室内,采集玉米三点斑叶蝉卯饲养玉米叶蝉缨翅缨小蜂至成虫.根据玉米叶蝉缨翅缨小蜂成虫的体色、触角、翅等形态特征对标本进行鉴定,并利用无损伤法提取样本基因组DNA,通过PCR扩增和测序对COⅠ和ITS2基因进行DNA条形码分子标记试验.[结果]形态学鉴定结果表明饲养获得的寄生蜂标本为玉米叶蝉缨翅缨小蜂.获得了该寄生蜂COⅠ和ITS2的部分序列,相似比对、遗传距离和分子进化树结果表明,玉米叶蝉缨翅缨小蜂COⅠ和ITS2序列分别与NCBI数据库中的同属其他种的相关基因有较高相似性,但存在一定遗传差异,可明显区分.[结论]获得的玉米缨翅缨小蜂的COⅠ和ITS2基因序列可作为玉米叶蝉缨翅缨小蜂的DNA条形码,为后续该寄生蜂的快速准确鉴定提供了分子数据.     

Oxidative DNA damage in rats exposed to extremely low frequency electro magnetic fields

Extremely low frequency (ELF) electromagnetic field (EMF) is thought to prolong the life of free radicals and can act as a promoter or co-promoter of cancer. 8-hydroxy-2'-deoxyguanosine (8OHdG) is one of the predominant forms of radical-induced lesions to DNA and is a potential tool to asses the cancer risk. We examined the effects of extremely low frequency electro magnetic field (ELF-EMF) (50 Hz, 0.97 mT) on 8OHdG levels in DNA and thiobarbituric acid reactive substances (TBARS) in plasma. To examine the possible time-dependent changes resulting from magnetic field, 8OHdG and TBARS were quantitated at 50 and 100 days. Our results showed that the exposure to ELF-EMF induced oxidative DNA damage and lipid peroxidation (LPO). The 8OHdG levels of exposed group (4.39+/-0.88 and 5.29+/-1.16 8OHdG/dG.10(5), respectively) were significantly higher than sham group at 50 and 100 days (3.02+/-0.63 and 3.46+/-0.38 8OHdG/dG.10(5)) (p<0.001, p<0.001). The higher TBARS levels were also detected in the exposure group both on 50 and 100 days (p<0.001, p<0.001). In addition, the extent of DNA damage and LPO would depend on the exposure time (p<0.05 and p<0.05). Our data may have important implications for the long-term exposure to ELF-EMF which may cause oxidative DNA damage.     

Beneficial effects of selenium on some enzymes of diabetic rat heart

It is known that selenium compounds can restore some metabolic parameters in experimental diabetes. However, as there are no, clear data about their effects on the altered antioxidant defense system of the diabetic heart, we aimed to investigate whether these beneficial effects extend to the alterations of some enzyme activities, which play important roles in antioxidant defense system. Diabetes was induced by streptozotocin (50 mg/kg body weight) and rats were then treated with sodium selenite (5 μmol/kg/d) for 4 wk. Sodium selenite treatment of the diabetic rats significantly restored the altered activities of glutathione- S-transferase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase, which are involved in the glutathione metabolism of the heart, but slightly but significantly decreased the high blood glucose level. In summary, the present study suggests that the beneficial effects of sodium selenite treatment appears to be the result of the restoration altered activities of the antioxidant enzymes in diabetic heart tissue.     

Influence of vanadium supplementation on oxidative stress factors in the muscle of STZ-diabetic rats

In recent years, the role of free radical damage consequent to oxidative stress is widely discussed in diabetic complications. In this aspect, the protection of cell integrity by trace elements is a topic to be investigated. Vanadium is a trace element believed to be important for normal cell function and development. The aim of the present study was to investigate the effect of vanadyl sulfate supplementation on the antioxidant system in the muscle tissue of diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg body weight) to male Swiss albino rats. The rats were randomly divided into 4 groups: Group I, control; Group II, vanadyl sulfate control; Group III, STZ-diabetic untreated; Group IV, STZ-diabetic treated with vanadyl sulfate. Vanadyl sulfate (100 mg/kg) was given daily by gavage for 60 days. At the last day of the experiment, rats were killed, muscle tissues were taken, homogenized in cold saline to make a 10% (w/v) homogenate. Body weights and blood glucose levels were estimated at 0, 30 and 60th days. Antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), as well as carbonic anhydrase (CA), myeloperoxidase (MPO) activities and protein carbonyl content (PCC) were determined in muscle tissue. Vanadyl sulfate administration improved the loss in body weight due to STZ-induced diabetes and decreased the rise in blood glucose levels. It was shown that vanadium supplementation to diabetic rats significantly decrease serum antioxidant enzyme levels, which were significantly raised by diabetes in muscle tissue showing that this trace element could be used as preventive for diabetic complications.     

Zinc supplementation ameliorates glycoprotein components and oxidative stress changes in the lung of streptozotocin diabetic rats

Zinc (Zn) is a component of numerous enzymes that function in a wide range of biological process, including growth, development, immunity and intermediary metabolism. Zn may play a role in chronic states such as cardiovascular disease and diabetes mellitus. Zn acts as cofactor and for many enzymes and proteins and has antioxidant, antiinflammatory and antiapoptotic effects. Taking into consideration that lung is a possible target organ for diabetic complications, the aim of this study was to investigate the protective role of zinc on the glycoprotein content and antioxidant enzyme activities of streptozotocin (STZ) induced diabetic rat tissues. Female Swiss albino rats were divided into four groups. Group I, control; Group II, control + zinc sulfate; Group III, STZ-diabetic; Group IV, diabetic + zinc sulfate. Diabetes was induced by intraperitoneal injection of STZ (65 mg/kg body weight). Zinc sulfate was given daily by gavage at a dose of 100 mg/kg body weight every day for 60 days to groups II and IV. At the last day of the experiment, rats were sacrificed, lung tissues were taken. Also, glycoprotein components, tissue factor (TF) activity, protein carbonyl (PC), advanced oxidative protein products (AOPP), hydroxyproline, and enzyme activities in lung tissues were determined. Glycoprotein components, TF activity, lipid peroxidation, non enzymatic glycation, PC, AOPP, hydroxyl proline, lactate dehydrogenase, catalase, superoxide dismutase, myeloperoxidase, xanthine oxidase, adenosine deaminase and prolidase significantly increased in lung tissues of diabetic rats. Also, glutathione levels, paraoxonase, arylesterase, carbonic anhydrase, and Na⁺/K⁺- ATPase activities were decreased. Administration of zinc significantly reversed these effects. Thus, the study indicates that zinc possesses a significantly beneficial effect on the glycoprotein components and oxidant/antioxidant enzyme activities.     

Investigation of binding properties of two ethidium derivatives with serum albumins: spectral and computational approach

The interaction mechanisms of two ethidium derivatives, 3,8-dibenzoylamino-5-ethyl-6-phenylphenantridinium chloride (E2) and 3,8-diphenylacetylamino-5-ethyl-6-phenylphenantridinium chloride (E3) with serum albumins (BSA and HSA) have been investigated by a combined experimental and computational approach. Fluorescence quenching and UV–vis results revealed that the interaction of derivatives with albumins resulted in formation of ground-state complexes and the obtained Stern–Volmer quenching constants designate the presence of a static component in the quenching mechanisms. Thermodynamic parameters (ΔH and ΔS values) point out the ionic interactions play the major role in E2-BSA, E2-HSA and E3-HSA complexes. The van der Waals interactions are dominant forces in E3-BSA complex. Moreover, the obtained results in this study were supported with computational analyzes which have same tendency.     

In vitro effects of compounds isolated from Sideritis brevibracteata on bovine kidney cortex glutathione reductase

Glutathione reductase (GR, E.C 1.6.4.2) is a flavoprotein that catalyzes NADPH-dependent reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH). The aim of this study was to investigate in vitro effects of phenolic compounds isolated from Sideritis brevibracteata on bovine kidney GR. The Sideritis species are widely found in nature and commonly used as medicinal plants. 7-O-glycosides of 8-OH-flavones (hypolaetin, isoscutellarein and 3'-hydroxy-4'-O-methylisoscutellarein) were isolated from aerial parts of Sideritis brevibracteata. These compounds inhibited bovine kidney cortex GR in a concentration-dependent manner. Kinetic characterization of the inhibition was also performed.     

Effect of Aloe vera (L.) Burm. fil. leaf gel and pulp extracts on kidney in type-II diabetic rat models

Significant degenerative changes were observed in the kidney tissue of untreated neonatal streptozotocin (n0STZ)-induced type-II diabetic rats. These degenerative changes were diminished in the kidney tissue of diabetic animals given glibenclamide and Aloe leaf gel and pulp extracts. Kidney lipid peroxidation levels were increased in diabetic rats compared to healthy rats; these levels were higher in rats treated with glibenclamide than in those which received Aloe extracts. Serum urea and creatinine levels were higher in diabetic rats in comparison to healthy rats. The administration of Aloe gel extract and glibenclamide decreased serum urea and creatinine levels in comparison to diabetic controls. Only A. vera leaf gel extract showed improvement both in histological and biochemical parameters suggesting a protective effect of A. vera on mild damage caused by type-II diabetes on kidney tissue.