Protective effects of resveratrol on hepatic ischemia reperfusion injury in streptozotocin-induced diabetic rats

Molecular and Cellular Biochemistry - Resveratrol (RSV) is a natural polyphenolic compound having antioxidant effects. This study was designed to investigate the protective effects of resveratrol...     

Effects of NMDA Receptor Blockade During the Early Development Period on the Retest Performance of Adult Wistar Rats in the Elevated Plus Maze

The elevated plus maze (EPM) is an animal model of anxiety used to test the effects of anxioselective drugs. The loss of the anxiolytic effect of drugs during the second exposure to the EPM is called the “one trial tolerance” (OTT) phenomenon. The present study was designed to investigate the relationship between the OTT phenomenon and N-methyl-d-aspartate (NMDA) receptor blockade in the early developmental period of rats. NMDA receptor blockade was accomplished using MK-801 treatment given between postnatal days 20–30. Beginning on postnatal day 20, the rats were subcutaneously injected with MK-801 twice a day at the nape of the neck for a period of 10 days (0.25 mg/kg). Increased open arm exploration was observed in MK-801-treated rats during trial 1 (p = 0.001) and trial 2 (p = 0.003). The rats spent less time in the closed arms as compared to the saline animals in trial 1 (p = 0.006), and this time decreased further in trial 2 (p = 0.02). The fecal boli of the MK-801 group was decreased in trial 1 as compared to the saline group (p = 0.01), but was not significantly different in trial 2 (p = 0.08). In conclusion, NMDA receptor blockade using MK-801 produced an anxiolytic-like effect in trials 1 and 2. Furthermore, OTT was not affected by NMDA receptor blockade.     

Recharacterization of the mammalian cytosolic type 2 (R)-β-hydroxybutyrate dehydrogenase as 4-oxo-l-proline reductase (EC 1.1.1.104)

Early studies revealed that chicken embryos incubated with a rare analog of l-proline, 4-oxo-l-proline, showed increased levels of the metabolite 4-hydroxy-l-proline. In 1962, 4-oxo-l-proline reductase, an enzyme responsible for the reduction of 4-oxo-l-proline, was partially purified from rabbit kidneys and characterized biochemically. However, only recently was the molecular identity of this enzyme solved. Here, we report the purification from rat kidneys, identification, and biochemical characterization of 4-oxo-l-proline reductase. Following mass spectrometry analysis of the purified protein preparation, the previously annotated mammalian cytosolic type 2 (R)-β-hydroxybutyrate dehydrogenase (BDH2) emerged as the only candidate for the reductase. We subsequently expressed rat and human BDH2 in Escherichia coli, then purified it, and showed that it catalyzed the reversible reduction of 4-oxo-l-proline to cis-4-hydroxy-l-proline via chromatographic and tandem mass spectrometry analysis. Specificity studies with an array of compounds carried out on both enzymes showed that 4-oxo-l-proline was the best substrate, and the human enzyme acted with 12,500-fold higher catalytic efficiency on 4-oxo-l-proline than on (R)-β-hydroxybutyrate. In addition, human embryonic kidney 293T (HEK293T) cells efficiently metabolized 4-oxo-l-proline to cis-4-hydroxy-l-proline, whereas HEK293T BDH2 KO cells were incapable of producing cis-4-hydroxy-l-proline. Both WT and KO HEK293T cells also produced trans-4-hydroxy-l-proline in the presence of 4-oxo-l-proline, suggesting that the latter compound might interfere with the trans-4-hydroxy-l-proline breakdown in human cells. We conclude that BDH2 is a mammalian 4-oxo-l-proline reductase that converts 4-oxo-l-proline to cis-4-hydroxy-l-proline and not to trans-4-hydroxy-l-proline, as originally thought. We also hypothesize that this enzyme may be a potential source of cis-4-hydroxy-l-proline in mammalian tissues.     

Ameliorative effect of supplementation with l-glutamine on oxidative stress,DNA damage,cell viability and hepatotoxicity induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in rat hepatocyte cultures

The most potent of the dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is a persistent and ubiquitous environmental contaminant. And the health impact of exposure to TCDD is of great concern to the general public. Recent data indicate that l-glutamine (Gln) has antioxidant properties and may influence hepatotoxicity. The objective of the present study was undertaken to explore the effectiveness of Gln in alleviating the hepatotoxicity of TCDD on primary cultured rat hepatocytes. Gln (0.5, 1 and 2 mM) was added to cultures alone or simultaneously with TCDD (0.005 and 0.01 mM). The hepatocytes were treated with TCDD and Gln for 48 h. Then cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC), total glutathione (TGSH) and total oxidative stress (TOS) levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by liver micronucleus assay (MN) and 8-oxo-2-deoxyguanosine (8-OH-dG). The results of MTT and LDH assays showed that TCDD decreased cell viability but not l-glutamine. TCDD also increased TOS level in rat hepatocytes and significantly decreased TAC and TGSH levels. On the basis of increasing doses, the dioxin in a dose-dependent manner caused significant increases of micronucleated hepatocytes (MNHEPs) and 8-OH-dG as compared to control culture. Whereas, in cultures exposured with Gln alone, TOS levels were not changed and TAC and TGSH together were significantly increased in dose-dependent fashion. The presence of Gln with TCDD modulated the hepatotoxic effects of TCDD on primary hepatocytes cultures. Noteworthy, Gln has a protective effect against TCDD-mediated DNA damages. As conclusion, we reported here an increased potential therapeutic significance of l-glutamine in TCDD-mediated hepatic injury for the first time.     

The cytotoxic and apoptotic effects of beta-blockers with different selectivity on cancerous and healthy lung cell lines

Molecular Biology Reports - β-blockers having specific affinities to β-adrenergic receptors are routinely used to treat cardiovascular problems. Additionally, it has been demonstrated...     

Examination of antimicrobial effect of fluoxetine in experimental sepsis model: An in vivo study

Since most infectious diseases can develop into sepsis, it is still a major medical problem. Some in-vivo studies showed promising properties of fluoxetine in the treatment of infections. This study aims the antimicrobial effect of fluoxetine on the inflammatory process used in the treatment of sepsis-modeled rats. Besides, to investigate the efficacy of fluoxetine on modifying the antibiotic effect of imipenem in the inflammatory response. An experimental sepsis model was divided into negative control, positive control, fluoxetine 5 mg/kg, imipenem 60 mg/kg, and combined (fluoxetine; imipenem). Procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP), lactate, myeloperoxidase activity (MPO), the inflammation markers interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alfa (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) levels were measured by enzyme-linked immunosorbent assay method. Oxidative stress markers, total oxidant status (TOS), total antioxidant status (TAS), total thiol (TT), and native thiol (NT) were measured using photometric methods. Oxidative stress index (OSI) was calculated according to TAS and TOS levels. The statistical analysis was performed by Statistical Package for Social Sciences version 22.0. After treatment with fluoxetine, imipenem, and combined groups, IL-1β, IL-6, TNF-α, MPO activity, MCP-1, hs-CRP, PCT, lactate, and the oxidative stress markers OSI, and disulfide levels were decreased (p < 0.05). The TT, NT, and TAS levels significantly statistically increased (p < 0.05). This research demonstrates that fluoxetine has effects as anti-inflammatory and antioxidant, and the combined treatment with antibioticum imipenem indicates positive synergistic effects in the experimental sepsis model.