Grape seed protects cholestatic rats liver from ischemia/reperfusion injury.

PURPOSE: To determine the effect of grape-seed extract against ischemia/reperfusion injury in cholestatic liver. METHODS: Eighteen Wistar albino rats were divided into three groups. In control and study groups, cholestasis was provided by bile duct ligation. Seven days later, the rats were subjected to 30 min hepatic ischemia, followed by 60 min of reperfusion. Oral administration of 50 mg/kg/day grape-seed extract was started 15 days before bile duct ligation and continued to the second operation in the study group. Serum, plasma and liver samples were taken. Laboratory analysis, tissue gluthation, malondialdehyde, myeloperoxidase levels and histopathological examination were performed. RESULTS: Significant decrease in liver gluthation level and significant increase in malondialdehyde level and myeloperoxidase activity were observed after ischemia/reperfusion in cholestatic rats. Serum and plasma levels for laboratory analysis were also significantly higher in cholestatic I/R group. Hepatic necrosis and fibrosis were detected in histopathological examination. Oral grape-seed extract administiration reversed all these parameters and histopathological findings except serum bilirubin levels. CONCLUSION: Oral grape-seed extract treatment can improve liver functions and attenuate the inflammation and oxidative stress in cholestatic ischemia/reperfusion injury.

Grape seed protects cholestatic rats liver from ischemia/reperfusion injury

ABSTRACT PURPOSE: To determine the effect of grape-seed extract against ischemia/reperfusion injury in cholestatic liver. METHODS: Eighteen Wistar albino rats were divided into three groups. In control and study groups, cholestasis was provided by bile duct ligation. Seven days later, the rats were subjected to 30 min hepatic ischemia, followed by 60 min of reperfusion. Oral administration of 50 mg/kg/day grape-seed extract was started 15 days before bile duct ligation and continued to the second operation in the study group. Serum, plasma and liver samples were taken. Laboratory analysis, tissue gluthation, malondialdehyde, myeloperoxidase levels and histopathological examination were performed. RESULTS: Significant decrease in liver gluthation level and significant increase in malondialdehyde level and myeloperoxidase activity were observed after ischemia/reperfusion in cholestatic rats. Serum and plasma levels for laboratory analysis were also significantly higher in cholestatic I/R group. Hepatic necrosis and fibrosis were detected in histopathological examination. Oral grape-seed extract administiration reversed all these parameters and histopathological findings except serum bilirubin levels. CONCLUSION: Oral grape-seed extract treatment can improve liver functions and attenuate the inflammation and oxidative stress in cholestatic ischemia/reperfusion injury.

Pharmacologic cholinesterase inhibition improves survival in acetaminophen-induced acute liver failure in the mouse.

BACKGROUND: Acetaminophen (APAP) is one of the most widely used analgesic and antipyretic pharmaceutical substances in the world and accounts for most cases of drug induced liver injury resulting in acute liver failure. Acute liver failure initiates a sterile inflammatory response with release of cytokines and innate immune cell infiltration in the liver. This study investigates, whether pharmacologic acetylcholinesterase inhibition with neostigmine diminishes liver damage in acute liver failure via the cholinergic anti-inflammatory pathway. METHODS: Acute liver failure was induced in BALB/c mice by a toxic dose of acetaminophen (APAP). Neostigmine and/or N-acetyl-cysteine (NAC) were applied therapeutically at set time points and the survival was investigated. Liver damage was assessed by serum parameters, histopathology and serum cytokine assays 12 h after initiation of acute liver failure. RESULTS: Serum parameters, histopathology and serum cytokine assays showed pronounced features of acute liver failure 12 h after application of acetaminophen (APAP). Neostigmine treatment led to significant reduction of serum liver enzymes (LDH (47,147 ± 12,726 IU/l vs. 15,822 ± 10,629 IU/l, p = 0.0014) and ALT (18,048 ± 4,287 IU/l vs. 7,585 ± 5,336 IU/l, p = 0.0013), APAP-alone-treated mice vs. APAP + neostigmine-treated mice), inflammatory cytokine levels (IL-1ß (147 ± 19 vs. 110 ± 25, p = 0.0138) and TNF-α (184 ± 23 vs. 130 ± 33, p = 0.0086), APAP-alone-treated mice vs. APAP + neostigmine-treated mice) and histopathological signs of damage.Animals treated with NAC in combination with the peripheral cholinesterase inhibitor neostigmine showed prolonged survival and improved outcome. CONCLUSIONS: Neostigmine is an acetylcholinesterase inhibitor that ameliorates the effects of APAP-induced acute liver failure in the mouse and therefore may provide new treatment options for affected patients.

'The effect of micronutrients on superoxide dismutase in senescent fibroblasts'.

The specific activities of zinc/copper (Zn/Cu)-superoxide dismutase (SOD-1) and manganese (Mn)-superoxide dismutase (SOD-2) were assayed in young passage 5 fibroblasts and in serially subcultured cells that were characterized as senescent at passages 15-35. SOD-1 and SOD-2 activities did not significantly change in senescent and young cells cultured in either routine medium [minimum essential medium 1 (MEM1)], or in Zn, Cu and Mn supplemented medium (MEM2) containing normal human plasma levels of the cations. SOD-1 and SOD-2 activities, however, underwent parallel progressive significant activity increases in senescent passage 20 and 25 cells, which peaked in value in passage 30 and 35 cells subcultured in supplemented medium (MEM3) containing triple human plasma levels of the cations. Concurrently, superoxide radical generation rates underwent progressive significant increases in senescent passage 15-25 cells, which peaked in value in passage 30 and 35 cells subcultured in MEM1 or MEM2. These rates, however, were significantly lowered in senescent cells subcultured in MEM3. We infer that it was only possible to significantly stimulate SOD-1 and SOD-2 activities in senescent MEM3 cultured cells enabling them to combat oxidative stress.

Membrane cholesterol modulates the cytolytic mechanism of myotoxin II, a Lys49 phospholipase A2 homologue from the venom of Bothrops asper.

Lys49 phospholipase A2 (PLA2) homologues present in crotalid snake venoms lack enzymatic activity, yet they induce skeletal muscle necrosis by a membrane permeabilizing mechanism whose details are only partially understood. The present study evaluated the effect of altering the membrane cholesterol content on the cytolytic activity of myotoxin II, a Lys49 PLA2 isolated from the venom of Bothrops asper, using the myogenic cell line C2C12 as a model target. Cell membrane cholesterol depletion by methyl-ß-cyclodextrin (MßCD) treatment enhanced the cytolytic action of myotoxin II, as well as of its bioactive C-terminal synthetic peptide p(115-129) . Conversely, cell membrane cholesterol enrichment by preformed cholesterol-MßCD complexes reduced the cytolytic effect of myotoxin II. The toxic actions of myotoxin I, a catalytically active PLA2 from the same venom, as well as of the cytolytic peptide melittin from bee venom, also increased in cholesterol-depleted cells. Although physical and functional changes resulting from variations in membrane cholesterol are complex, these findings suggest that membrane fluidity could be a relevant parameter to explain the observed modulation of the cytolytic mechanism of myotoxin II, possibly influencing bilayer penetration. In concordance, the cytolytic effect of myotoxin II decreased in direct proportion to lower temperature, a physical factor that affects membrane fluidity. In conclusion, physicochemical properties that depend on membrane cholesterol content significantly influence the cytolytic mechanism of myotoxin II, reinforcing the concept that the primary site of action of Lys49 PLA2 myotoxins is the plasma membrane.

Antioxidant activity of various solvent extracts from Allomyrina dichotoma (Arthropoda: Insecta) larvae.

This study was under taken to evaluate the antioxidant properties of larvae extracts of Allomyrina dichotoma. The antioxidant activities of various larvae extracts of water, methanol, ethyl-acetate, chloroform, and hexane were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion radical and singlet oxygen ((1)O(2)). The methanolic larvae extracts displayed the greatest effect in DPPH radical scavenging assay, but the reducing activity of larvae extracts was weaker in the superoxide anion radical assay. However, methanol (ME) and chloroform extracts (CE) could be compared to ascorbic acid in (1)O(2) quenching ability. ME (the concentration of 50% (1)O(2) quenching, QC(50)=0.080mg/ml) and CE (QC(50)=0.051mg/ml) extracts had 1.7, 2.7 times better efficiency than ascorbic acid (QC(50)=0.138mg/ml), respectively. Also the extracts were found to protect biological systems in Escherichia coli and lactate dehydrogenase against detrimental effects of (1)O(2) of type II photosensitization in vitro. The ability of larvae extracts to scavenge free radicals could significantly change contents of GA equivalent, an important factor for the potency of antioxidant capacity. The results suggest that our study may contribute to the development of new bioactive products with potential applications to reduce oxidative stress in living organisms involving reactive oxygen species as well as play a vital role in insect organisms against oxidative damage of undesirable conditions.