Liver Mitochondrial Fractions Research Articles

Genista cephalantha Spach. protects against acetaminophen-induced liver failure via preserving the glutathione redox system, reducing inflammatory response, and inhibiting hepatocyte death in rats.

The current study was conducted to assess the protective mechanisms of n-BuOH fraction from the aerial part of Genista cephontala (BEGC) on APAP-induced liver injury compared to necrostatine-1 (Nec-1). A model of APAP-induced hepatotoxicity was created in male rats by injecting a single dose; 1000 mg/kg APAP, the protective effect was performed with (200 mg/kg; 10 days) BEGC compared to Nec-1, (1.8 mg/kg). BEGC or NeC-1 pretreatment significantly abolished impaired effects in APAP-rats, by decreasing the generation of TBARS and ROS in mitochondrial and cytosolic fractions and maintaining liver function activities. A marked response was observed in the levels of both GSH and GSH-system enzymes in liver homogenates and mitochondrial fractions to BEGC. BEGC/ Nec-1 successfully regulated the inflammatory mediators (IL-β, TNF-α, HMGB1, and acHMGB1) and MPO levels. During APAP treatment, no caspase-3 or -8 activity was detected, and the level of fk18; M30 was higher than the levels of cck18; M65. Moreover, RIPK3 and MLKL levels were increased in the APAP group. These results suggested that necroptosis predominates during the APAP liver injury model. Interestingly, these necroptotic factors were significantly down-regulated by BEGC treatment. Both biochemical and histopathological findings were consistent with each other. From all these findings, the hepatoprotective effect of BEGC could be due to the abundance of polyphenols identified by LC-MS/MS analysis, as well as the synergistic interactions of all contents.

The Final Pathway of Carbohydrate Oxidation: Revisiting the mLOC

The confirmation of the Intracellular Lactate Shuttle proposed by Brooks and colleagues in 1998 revolutionized the way lactate metabolism was studied in the field of exercise physiology, nutrition, metabolism, and medicine. Previous investigations identified the structure of the mitochondrial Lactate Oxidation Complex (mLOC) which includes MCT1, LDH, COX4, and CD147. While the predominant view in research and textbooks was that pyruvate was imported into the mitochondria to be oxidized it wasn’t until 2009 that Jiang and Colleagues elucidated the mitochondrial pyruvate carrier (mPC). Knowing this, many researchers developed their questions around either pyruvate or lactate metabolism, which may have led to confusion in the field since both substrates play an important role in carbohydrate oxidation. This dilemma led us to the hypothesis that the mPC is in fact an extended member of the mLOC. Mixed skeletal muscle and liver were excised and whole blood was collected post-mortem from (n=5) 4-month-old C57B/l6 mice. Tissues were homogenized in an isotonic solution supplemented with a protease and phosphatase inhibitor. Blood was resuspended in H2O to rupture the cell membranes and the lysates (RBC) were used as negative controls. Mitochondria were isolated by differential centrifugation and resuspended in RIPA buffer. Protein concentrations of tissues were determined using a BCA standard. Western blotting was performed by loading 20 ug of each lysate, separated on an SDS-PAGE gel, and transferred to a PVDF membrane. Membranes were blocked and probed for MCT1(1:1000), mPC1 (1:500), COX4(1:1000), LDHA (1:1000). An SDS-PAGE was repeated and the mPC was excised from the gel. A trypsin digest was performed to isolate the peptides and then analyzed by one-dimensional LCMS/MS at the UC Berkeley QB3 proteomics/mass spectrometry lab. For cDNA preparation, RNA was extracted from 15 mg of skeletal muscle using the Qiagen RNeasy Fibrous tissue kit, reverse transcribed, and concentrated using Quibit ssDNA kit. Quantitative PCR was run on a QuantStudio3 using Power SYBR Green chemistry to confirm the presence of mPC1 in skeletal muscle. Our results revealed that mPC1 was expressed in skeletal muscle along with other genes associated with the mLOC. Immunoblots of mitochondrial lysates contained MCT1, mPC1, LDH, and COX4 in both the skeletal muscle and liver mitochondrial fractions. As expected, MCT1 was also present in RBC lysates as the MCTs are present in both the sarcolemma and mitochondrial membrane. Moreover, LCMS/MS analysis confirmed the presence of mPC1 corroborating our immunoblots. Colocalization using immunocytochemistry confirms the revised mLOC structure. Accordingly, both the pyruvate and lactate transporters assist in maintaining the redox balance and varying rates of carbohydrate oxidation during changing physiological conditions. This promising data has implications for a variety of fields ranging from cancer biology to exercise physiology. NIH Grant #1 R01 AG059715-01 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Investigation into MAO B-Mediated Formation of CC112273, a Major Circulating Metabolite of Ozanimod, in Humans and Preclinical Species: Stereospecific Oxidative Deamination of (S)-Enantiomer of Indaneamine (RP101075) by MAO B.

Ozanimod, recently approved for treating relapsing multiple sclerosis, produced a disproportionate, active, MAO B-catalyzed metabolite (CC112273) that showed remarkable interspecies differences and led to challenges in safety testing. This study explored the kinetics of CC112273 formation from its precursor RP101075. Incubations with human liver mitochondrial fractions revealed K Mapp, V max, and intrinsic clearance (Clint) for CC112273 formation to be 4.8 μM, 50.3 pmol/min/mg protein, and 12 μl/min/mg, respectively, whereas Michaelis-Menten constant (K M) with human recombinant MAO B was 1.1 μM. Studies with liver mitochondrial fractions from preclinical species led to K Mapp, V max, and Clint estimates of 3.0, 35, and 33 μM, 80.6, 114, 37.3 pmol/min/mg, and 27.2, 3.25, and 1.14 μl/min/mg in monkey, rat, and mouse, respectively, and revealed marked differences between rodents and primates, primarily attributable to differences in the K M Comparison of Clint estimates revealed monkey to be ∼2-fold more efficient and the mouse and rat to be 11- and 4-fold less efficient than humans in CC112273 formation. The influence of stereochemistry on MAO B-mediated oxidation was also investigated using the R-isomer of RP101075 (RP101074). This showed marked selectivity toward catalysis of the S-isomer (RP101075) only. Docking into MAO B crystal structure suggested that although both the isomers occupied its active site, only the orientation of RP101075 presented the C-H on the α-carbon that was ideal for the C-H bond cleavage, which is a requisite for oxidative deamination. These studies explain the basis for the observed interspecies differences in the metabolism of ozanimod as well as the substrate stereospecificity for formation of CC112273. SIGNIFICANCE STATEMENT: This study evaluates the enzymology and the species differences of the major circulating metabolite of ozanimod, CC112273. Additionally, the study also explores the influence of stereochemistry on MAO B-catalyzed reactions. The study is of significance to the DMD readers given that this oxidation is catalyzed by a non-cytochrome P450 enzyme, and that marked species difference and notable stereospecificity was observed in MAO B-catalyzed biotransformation when the indaneamine enantiomers were used as substrates.

Cerium oxide nanoparticles and metformin increase the reliability of the prooxidant/antioxidant balance and the survival of ageing rats

In comparison with the action of metformin — mimetic of the calorie restricted diet, which prolong the animals lifespan, it has been studied the effect of nanoparticles of cerium dioxide (CeO2 NPs (1-2 nm)) on survival, physiological indices (the concentration of thyroxine, rectal temperature), as well as biochemical indices (content of lipid hydroperoxides, aconitase, glutathione peroxidase, glutaredoxin, glutathione reductase, NADP+ -dehydrogenase activities (glucose-6-phosphate-, malate- and isocitrate dehydrogenase)) in serum, liver mitochondrial and postmitochondrial fraction of ageing rats. It has been found that the prolonged use of CeO2 NPs with drinking water (0.25-0.30 mg/kg of body weight per day) and metformin (100-110 mg/kg of body weight per day) from 670 days after the birth lead to a significant increase in survival (the median survival of control rats was 900, in animals treated with CeO2 NPs — 960, and metformin — 990 days), a decrease in rectal temperature, a slowdown in the decrease in the level of thyroxine in blood, and normalization of the prooxidant/antioxidant balance in liver and blood tissues. Calculated integral index of reliability of prooxidant-antioxidant balance (reliability coefficient) in the studied tissues of rats in response to the application of the CeO2 NPs increased 4.99 times, and metformin — 4.94 times compared to intact animals. The data obtained allow us concluding about the prospects of the CeO2 NPs, as well as metformin for the development of geroprotector drugs, increasing the healthspan and survival of an ageing organism.

Age-Related Effects of Orthovanadate Nanoparticles Involve Activation of GSH-Dependent Antioxidant System in Liver Mitochondria.

Vanadium is an important ultra-trace element nowadays attracting attention with particular emphasis on medical application. But the therapeutic application of vanadium-based drugs is still questionable and restricted due to some toxic side effects. It was found that unique redox properties of vanadium in nanoform provided antioxidant activity and prevented oxidative disturbance in cells in vitro. Though, on the organism level, ambiguous effects of vanadium-based nanoparticles were observed. In this study, the age-related features of prooxidant/antioxidant balance in blood serum and liver mitochondrial and postmitochondrial fractions of 3 and 18-month-old Wistar male rats treated with orthovanadate nanoparticles (GdVO4/Eu3+, 8 × 25nm) within 2months have been investigated. Prooxidant potential-related indexes were the content of lipid hydroperoxides as well as aconitase activity. Activity of glutathione peroxidase, glutathione-S-transferase, glutaredoxin, glutathione reductase, glucose-6-phosphate dehydrogenase, and NADPH-dependent isocitrate dehydrogenase designated the tissue antioxidant potential. Based on the obtained values, the integral index of the prooxidant/antioxidant balance-the reliability coefficient (Kr) has been calculated. The data show that due to activation some chain links of GSH-dependent antioxidant system, GdVO4/Eu3+ nanoparticles increase the reliability of the prooxidant-antioxidant balance in tissues and especially in the liver mitochondria of old animals (Kr in mitochondria of young rats was 2.94, and in mitochondria of old ones-9.83 conventional units). Detected in vitro glutathione peroxidase-like activity of the GdVO4/Eu3+ nanoparticles is supposed to be among factors increasing the reliability of the system. So, for the first time, the beneficial effect of the long-term orthovanadate nanoparticle consumption in old males has been discovered.

Effect of essential lipophilic nutrients on free radical processes in liver mitochondrial fraction of the tumor-bearing rats

Oxidative stress is a universal mechanism of cellular damage of hepatocytes, leading to a decrease in the detoxification function of the liver, which is especially important during oncogenesis. An early correction of these mechanisms by lipophilic essential nutrients could increase the effectiveness of antitumor treatment and prevent the development and progress of cancer. Aim to study the effect of separate and combined use of ω-3 PUFA and vitamin D3 on the intensity of free radical processes, mitochondrial swelling and cytochrome c content in the liver mitochondrial fraction of the tumor-bearing rats during the intensive growth of the tumor has been studied. Material and methods. Studies were carried out on white outbred female rats weighing 130-150 g, which were divided into 5 groups (each n=12). Guerin's carcinoma was used as a model of malignant neoplasm. Carcinoma transplantation was carried out by subcutaneous injection of 0.5 ml of a 30% suspension of cancer cells into saline in the upper thigh region of the right limb. ω-3 PUFAs (120 mg/kg of body weight, per os) and vitamin D3 (600 IU/kg of body weight, per os) were pre-administered for 28 days before the transplantation of Guerin's carcinoma and after transplantation for the entire period of tumor growth in the body (14 days). Liver mitochondrial fraction was isolated by differential centrifugation. The intensity of lipid peroxidation was judged by using spectrophotometry by the content of primary, secondary, and tertiary products in isopropanol extracts. The rate of formation of the superoxide radical was recorded in a test with nitro-blue tetrazolium, the swelling of mitochondria was assessed by a decrease in the optical density of isolated mitochondria, the content of cytochrome c in the mitochondrial and cytosolic fractions was determined by multi-wavelength visible light spectroscopy. Results and discussion. An increase in the content of primary (diene and triene conjugates), secondary (ketodienes; conjugated trienes; TBA-active products) and terminal (Schiff bases) lipid peroxidation products with a simultaneous increase in the generation of superoxide anion-radical was found in the liver mitochondrial fraction of the tumorbearing rats. With the administration of ω-3 PUFA and vitamin D3, both separately and especially when used together, a decrease in the intensity of free radical processes in liver mitochondrial fraction of tumor-bearing rats has been observed. At the same time, mitochondrial swelling decreased, this prevented the release of cytochrome c from mitochondria into cytosol. Conclusion. The administration of the complex ω-3 PUFA and vitamin D3 reduces the processes of lipid peroxidation in the mitochondrial fraction of the liver of tumor-bearing rats while simultaneously restoring the functional ability of mitochondria.

Generation of 1,25-dihydroxyvitamin D3 in Cyp27b1 knockout mice by treatment with 25-hydroxyvitamin D3 rescued their rachitic phenotypes

We have reported that 25-hydroxyvitamin D3 [25(OH)D3] binds to vitamin D receptor and exhibits several biological functions directly in vitro. To evaluate the direct effect of 25(OH)D3 in vivo, we used Cyp27b1 knockout (KO) mice, which had no detectable plasma 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] when fed a diet containing normal Ca and vitamin D. Daily treatment with 25(OH)D3 at 250 μg kg-1 day-1 rescued rachitic phenotypes in the Cyp27b1 KO mice. Bone mineral density, female sexual cycles, and plasma levels of Ca, P, and PTH were all normalized following 25(OH)D3 administration. An elevated Cyp24a1 mRNA expression was observed in the kidneys, and plasma concentrations of Cyp24a1-dependent metabolites of 25(OH)D3 were increased. To our surprise, 1,25(OH)2D3 was detected at a normal level in the plasma of Cyp27b1 KO mice. The F1 to F4 generations of Cyp27b1 KO mice fed 25(OH)D3 showed normal growth, normal plasma levels of Ca, P, and parathyroid hormone, and normal bone mineral density. The curative effect of 25(OH)D3 was considered to depend on the de novo synthesis of 1,25(OH)2D3 in the Cyp27b1 KO mice. This suggests that another enzyme than Cyp27b1 is present for the 1,25(OH)2D3 synthesis. Interestingly, the liver mitochondrial fraction prepared from Cyp27b1 KO mice converted 25(OH)D3 to 1,25(OH)2D3. The most probable candidate is Cyp27a1. Our findings suggest that 25(OH)D3 may be useful for the treatment and prevention of osteoporosis for patients with chronic kidney disease.

The intensity of free radical processes in the liver mitochondrial fraction under the conditions of toxic injury and correction by the 3,4-dihydropyrimidine-2-one ammonium derivative

The intensity of free radical processes in the liver mitochondrial fraction under the conditions of toxic injury and correction by the 3,4-dihydropyrimidine-2-one ammonium derivative

Evaluating a Second Generation Phytochemical Nrf2 Activator on Proteostasis and Cytoprotective Gene Expression in Vivo

Aging is associated with increases in oxidative stress. Redox imbalance occurs when production of reactive oxygen species (ROS) exceeds the capacity of antioxidant enzymes to eliminate ROS. Increased levels of intracellular ROS can compromise proteostasis by causing irreversible damage to proteins. The transcription factor nuclear factor erythroid-derived 2-like 2 (Nrf2) mediates the cellular endogenous antioxidant defense system by regulating antioxidant enzymes that are cytoprotective against ROS. Nrf2 can be activated phytochemically through the supplement Protandim. Previous work from our lab has demonstrated that a phytochemical based Nrf2 activator improves proteostasis in skeletal muscle in vivo. Recently, we have begun to characterize a second generation Nrf2 activator (PB125) that has increased anti-inflammatory action in addition to anti-oxidant properties. Since inflammation can blunt protein synthetic responses, we speculated that PB125 might provide additional benefits on proteostatic processes. PURPOSE: The purpose of the present study was to examine in vivo the effects of three different doses (10, 100, and 300 ppm) of PB125 supplementation on Nrf2 activation and proteostasis. METHODS: 60 male CB6F1 mice aged 10–11 months were assigned to diets containing low, medium, or high doses of product PB125 in a 5 week feeding study. Mice were isotopically labeled with 8% deuterium oxide (D2O) to simultaneously measure protein and DNA fractional synthesis rates (FSR) in liver, heart, and skeletal muscle. Nrf2 activation was assessed through analysis of gene expression profiles via Affymetrix GeneChip microarray. RESULTS: Proteostatic mechanisms were increased in the liver mitochondrial fraction in the 10 ppm treatment group (18.9 vs 16.3 FSR%/day, p<0.05). However, there were no differences in proteostatic mechanisms in heart or skeletal muscle. At 100 ppm, there was up-regulation of Nrf2-dependent cytoprotective genes (Akr1d1, Gpx2, Gclm, Fthl17b, 3.82, 1.84, 1.42, 1.64-fold increase). CONCLUSION: From our data we were able to conclude that all three doses were safe, and that 100 ppm was effective at activating Nrf2. In addition, there was an indication of increased proteostatic processes in the liver, but not heart or skeletal muscle, perhaps due to the healthy status of the mice.

In-vitro mercaptopyruvate sulfurtransferase species comparison in humans and common laboratory animals

Cyanide is a metabolic poison that inhibits cytochrome c oxidase. Its broad applications in manufacturing and history as an agent of warfare/terror highlight the limitations in approved cyanide antidotes for mass casualties. Sulfanegen, a pre-clinical antidote for cyanide poisoning, exploits an endogenous detoxification pathway and should be amenable to mass-casualty scenarios. Because human studies are unethical, determination of appropriate animal species as models in translational studies for FDA approval under the “Animal Rule” are critical. Here, we compared the specific activities of mercaptopyruvate sulfurtransferase (MST, required for sulfanegen’s activity), across common laboratory models of cyanide intoxication, and humans. Human MST activities in erythrocytes (measured as micromole pyruvate/min/106 rbc) were closest to those of Swiss-Webster mice and NZW rabbits. Similar species were selected for a more detailed tissue-specific comparison of MST activities. NZW Rabbits were closest to humans in the liver and kidney mitochondrial fractions, the Swiss-Webster mouse was closest to humans in the liver cytosolic fraction, while C57BL/6 mouse was closest in the kidney cytosolic fraction. These data comparing MST activities in animal models will help justify the use of those specific animals per the animal rule. Interestingly, statistically significant differences were found in MST activities of liver mitochondria between human smokers and non-smokers (p=0.0030).

The effect of hibernation on lipids of the liver mitochondrial fraction in the Yakut ground squirrel Spermophilus undulatus

We demonstrated that the level of phospholipids in the liver mitochondrial fraction is increased by 60% during the winter hibernation season in the Yakut ground squirrel S. undulatus; the phospholipid composition in sleeping animals is characterized by an increase in phosphatidylethanolamine compared with summer animals. A sharp increase in the level of cholesterol, as well as fatty acid, monoglycerides, and diglycerides was found in the mitochondrial fraction of hibernating ground squirrels in relation to summer ground squirrels. Functional changes during hibernation concern the level of phosphatidylserine (the growth in sleeping animals compared with active animals). Seasonal modification of the lipid composition of the liver mitochondria (particularly, an increase in the level of cholesterol) can play a role in the resistance of mitochondria to the seasonal increase in the level of fatty acids in the liver. Lipids of the liver mitochondrial fraction are involved in the ground squirrel adaptation to the hibernation season.

Bioactive compounds in Costus afer Ker Gawl leaves and stem fractions protect against calcium ion-induced mitochondrial membrane permeability transition

Objective: Costus afer Ker Gawl is an African ethno-medicinal plant used as a therapeutic for the treatment of oxidative stress-related diseases. This study was designed to identify the most active fractions of C.afer leaves and stem against calcium(II) (Ca2+)-induced mitochondrial membrane permeability transition (MPT). Methods: C.afer leaves and stem were extracted using 70% methanol and subsequently subjected to successive solvent partitioning method to separate it into hexane, ethyl acetate, n-butanol and aqueous fraction of C.afer leaves and stem. Rat liver mitochondrial fractions were isolated using differential centrifugation technique, and mitochondrial MPT was assessed using a spectrophotometric method. Results: Data showed that n-butanol fractions of C.afer leaves and stem exhibited a significantly high inhibition of Ca2+-induced mitochondrial MPT than other test fractions and standard spermine. Conclusion: n-butanol fractions of Costus afer leaves and stem possess bioactive compounds with chemoprotective activity against Ca2+-induced mitochondrial MPT. Furthermore, it is suggested that n-butanol fractions of C.afer leaves and stem could be harnessed for bioactive compounds that can be used in the treatment of mitochondria-associated neurodegenerative diseases.

Bioactive compounds in Costus afer Ker Gawl leaves and stem fractions protect against calcium ion-induced mitochondrial membrane permeability transition

Objective: Costus afer Ker Gawl is an African ethno-medicinal plant used as a therapeutic for the treatment of oxidative stress-related diseases. This study was designed to identify the most active fractions of C.afer leaves and stem against calcium(II) (Ca2+)-induced mitochondrial membrane permeability transition (MPT). Methods: C.afer leaves and stem were extracted using 70% methanol and subsequently subjected to successive solvent partitioning method to separate it into hexane, ethyl acetate, n-butanol and aqueous fraction of C.afer leaves and stem. Rat liver mitochondrial fractions were isolated using differential centrifugation technique, and mitochondrial MPT was assessed using a spectrophotometric method. Results: Data showed that n-butanol fractions of C.afer leaves and stem exhibited a significantly high inhibition of Ca2+-induced mitochondrial MPT than other test fractions and standard spermine. Conclusion: n-butanol fractions of Costus afer leaves and stem possess bioactive compounds with chemoprotective activity against Ca2+-induced mitochondrial MPT. Furthermore, it is suggested that n-butanol fractions of C.afer leaves and stem could be harnessed for bioactive compounds that can be used in the treatment of mitochondria-associated neurodegenerative diseases.

A diet-induced Sprague–Dawley rat model of nonalcoholic steatohepatitis-related cirrhosis

Certain modified diets containing saturated fatty acids, cholesterol or fructose lead to the development of nonalcoholic steatohepatitis (NASH)-related fibrosis in rodents; however, progression to cirrhosis is rare. Experimental liver cirrhosis models have relied on genetic manipulation or administration of hepatotoxins. This study aimed to establish a reliable dietary model of NASH-related cirrhosis in a relatively short period. Male Sprague–Dawley rats (9 weeks of age) were randomly assigned to normal, high-fat (HF), or two types (1.25% or 2.5% cholesterol) of high-fat and high-cholesterol (HFC) diets for 18 weeks. All HFC diets contained 2% cholic acid by weight. Histopathological analysis revealed that the HFC diets induced obvious hepatic steatosis, inflammation with hepatocyte ballooning and advanced fibrosis (stage 3–4) in all 12 rats at 27 weeks of age. In contrast, all five rats given the HF diet developed mild steatosis and inflammation without fibrosis. The amount of cholesterol in the liver and hepatocellular mitochondrial and microsomal fractions was significantly higher in rats fed the HFC diets than the normal or HF diets. The HFC diets significantly suppressed mRNA levels of microsomal triglyceride transfer protein, adenosine triphosphate binding cassette transporter G5, bile acid CoA: amino acid N-acyltransferase and bile salt export pump, as well as the enzymatic activity of carnitine palmitoyltransferase in the liver. In conclusion, the HFC diets induced liver cirrhosis in conjunction with hepatic features of NASH in Sprague–Dawley rats within 18 weeks, and altered gene expression and enzyme activity to accumulate lipid and bile acid in the liver.

Activity of liver mitochondrial Krebs cycle NAD+-dependent dehydrogenases in rats with hepatitis induced by acetaminophen under conditions of alimentary protein deficiency

Activity of isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, malate dehydrogenase, and the NAD+/NADН ratio were studied in the liver mitochondrial fraction of rats with toxic hepatitis induced by acetaminophen under conditions of alimentary protein deficiency. Acetaminophen-induced hepatitis was characterized by a decrease of isocitrate dehydrogenase, α-ketoglutarate dehydrogenase and malate dehydrogenase activities, while the mitochondrial NAD+/NADН ratio remained at the control level. Modeling of acetaminophen-induced hepatitis in rats with alimentary protein deficiency caused a more pronounced decrease in the activity of studied Krebs cycle NAD+-dependent dehydrogenases and a 2.2-fold increase of the mitochondrial NAD+/NADН ratio.

Oral pharmacokinetics and in-vitro metabolism of metyrapone in male rats.

The purpose of this study was to investigate the pharmacokinetics of a single oral administration of metyrapone (MP) and metabolites produced from it in male Wistar rats, and the major tissues and enzymes involved in the production of the MP metabolites. Furthermore, the MP metabolism in human liver subcellular fractions was compared with that in rats. High-performance liquid chromatography with ultraviolet detection (HPLC-UV) was used to determine the concentrations of MP and its metabolites in plasma and urine after administration, and the production activity of MP metabolites in subcellular fractions of various tissues. Plasma concentration of MP was rapidly increased and decreased, and the primary metabolite, metyrapol (MPOL), was immediately produced. The production activity of MPOL was substantially inhibited by an 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor in the rat and human liver microsomal and mitochondrial fractions. In the liver cytosolic fraction, the activity was inhibited by a carbonyl reductase inhibitor in the humans but not rats. In this study, we elucidated the plasma pharmacokinetics of MP and its metabolites in male rats after an oral administration. MPOL is most likely to be produced by 11β-HSD1 in the male rats and humans.

Activity of liver mitochondrial NAD+-dependent dehydrogenases of the krebs cycle in rats with acetaminophen-induced hepatitis developed under conditions of alimentary protein deficiency

Activity of isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, malate dehydrogenase, and the NAD(+)/NADН ratio were studied in the liver mitochondrial fraction of rats with toxic hepatitis induced by acetaminophen under conditions of alimentary protein deprivation. Acetaminophen-induced hepatitis was characterized by a decrease of isocitrate dehydrogenase, α-ketoglutarate dehydrogenase and malate dehydrogenase activities, while the mitochondrial NAD(+)/NADН ratio remained at the control level. Modeling of acetaminophen-induced hepatitis in rats with alimentary protein caused a more pronounced decrease in the activity of NAD(+)-dependent dehydrogenases studied and a 2.2-fold increase of the mitochondrial NAD(+)/NADН ratio. This suggests that alimentary protein deprivation potentiated drug-induced liver damage.

Eugenia caryophyllus Extract Exerts Hypocholesterolemic and Antioxidant Effects in High-Cholesterol-Fed Rats

Background: Eugenia caryophyllus (clove) is an important aromatic household spice. The plant is believed to possess medicinal properties and is commonly used in herbal preparations by traditional healers in the treatment of different ailments and diseases. Objectives: We investigated the lipid-lowering and antioxidant effects of aqueous extract of Eugenia caryophyllus on high-cholesterol-fed rats. Materials and Methods: Cholesterol (40 mg/0.3 mL) was administered to induce hypercholesterolemia in rats by oral gavage, and Eugenia caryophyllus (100 or 200 mg/kg) and Questran (0.26 g/kg) were administered five times a week for eight consecutive weeks. Serum lipid-profiles, lipid peroxidation (LPO), and antioxidant parameters were examined in liver and heart post mitochondrial fraction (PMF). Aspartate and alanine aminotransferase (ALT and AST) activities and liver tissue histology were used to evaluate tissue toxicity. Results: Hypercholesterolemia produced a noticeable decrease in serum HDL-c, whereas a concurrent elevation in serum LDL-c, total cholesterol, and triglycerides as well as serum ALT and AST was observed. Furthermore, hypercholesterolemia remarkably decreased antioxidant status, but LPO content was increased. These indices were significantly attenuated in hypercholesterolemic rats treated with E. caryophyllus extract (100 or 200 mg/kg of body weight). Specifically, reduced glutathione (GSH) concentration was increased in a dose dependent manner in liver and heart PMF. Conclusions: These results demonstrate that the hypolipidemic and antioxidative effects of aqueous extract of E. caryophyllus might be due to its ability to ameliorate lipid profiles, enhance antioxidant activities, and delay the lipid peroxidation process. This confirms the previously identified protective roles of E. caryophyllus in human health.

Antioxidant Potential and Toxicity Study of the Cerium Oxide Nanoparticles Synthesized by Microwave-Mediated Synthesis.

Monodispersed cerium oxide nanoparticle has been synthesized by microwave-mediated hydrothermal as well as microwave-mediated solvothermal synthesis. X-ray diffraction (XRD) data shows that the synthesized particles are single phase. SEM and TEM analysis suggest that particle synthesized by microwave-mediated solvothermal method are less agglomerated. In vitro toxicology study of the synthesized nanoceria particles has shown good free radical scavenging activity for NO and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assayed except superoxide radical within a concentration range of 25 to 75 ng ml(-1). Nanoceria particle also showed inhibition of Fe-ascorbate-induced lipid peroxidation (LPx) in chick liver mitochondrial fractions. Solvothermally synthesized nanoceria showed better protection against Fe-ascorbate-induced LPx than the hydrothermal one while the hydrothermally synthesized nanoceria showed better DPPH and NO scavenging activity. The ceria nanoparticles also prevented Fe-ascorbate-H2O2-induced carbonylation of bovine serum albumin in a dose-dependent manner. At higher concentration, i.e., 100 ng ml(-1), the synthesized nanoparticles showed a reverse trend in all the parameters measured indicating its toxicity at higher doses.

Tamarind seed extract mitigates the liver oxidative stress in arthritic rats

Although arthritis is primarily a joint disorder that mainly targets the articular cartilage and subchondral bone, several recent investigations have reported oxidative burst and vital organ damage that are being considered as secondary complications of arthritis. The continuous generation of free radicals like reactive oxygen and nitrogen species is considered as a key culprit in the initiation and propagation of oxidative damage. In addition, activation of T and B cells, macrophages, inflammatory mediators such as TNF-α, IL-1β and IL-6 aggravates the oxidative damage of the vital organs, particularly the liver. The current piece of work demonstrates oxidative stress in the liver of arthritic rats and its amelioration by the procyanidin-rich tamarind seed extract (TSE). The arthritic liver homogenate, mitochondrial and cytosolic fractions were found with increased levels of oxidative stress markers including free radicals. As a consequence, depletion in the levels of glutathione, total thiols, glutathione peroxidase and reductase was evident. Furthermore, the activities of endogenous antioxidant enzymes like superoxide dismutase, catalase and glutathione-S-transferase were found to be significantly altered. The increased and decreased activity of transaminases respectively in serum and liver, along with histological observations, further confirms the liver damage. Unfortunately, the commonly used drugs like NSAIDs and DMARDs have failed to prevent oxidative damage, rather they were found to be the inducers themselves. Interestingly, TSE supplementation was found to significantly inhibit oxidative burst in the liver and maintain homeostasis. Thus, the study clearly demonstrates the protective efficacy of TSE against arthritis-associated oxidative liver damage, including mitochondrial oxidative burst and its associated secondary complications.