Mouse Lactate Dehydrogenase Research Articles

A Comprehensive Pathophysiologic, Histologic, and Biochemical Analysis of Buthus paris (C. L. Koch, 1839) Venom.

Buthus species, including B paris, are classified as one of the most dangerous scorpion genera in Morocco, implicated in several cases of human death. Our objective is to characterize, for the first time, the toxicity and histopathologic and biochemical impacts of B paris venom. We investigated the experimental pathophysiology of B paris venom by examining histologic changes in vital organs (heart, kidneys, liver, and lungs) and assessing biochemical enzymatic markers (alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, creatine phosphokinase, urea, and creatinine) in mice injected subcutaneously with 2 doses of 400 and 450 mg·kg-1. Our results showed that the subcutaneous median lethal dose of B paris venom was around 0.52 mg·kg-1. Histologic findings revealed significant tissue damage in the previously mentioned vital organs, confirmed through biochemical analysis indicating impaired heart and liver functions. Additionally, an increase in urea, creatinine, and glucose levels occurred following B paris venom injection. Our findings show that B paris venom exhibits a high level of experimental toxicity. These results highlight the potentially lethal nature of this venom and emphasize the potential medical importance of this species.

GSK2795039 prevents RIP1-RIP3-MLKL-mediated cardiomyocyte necroptosis in doxorubicin-induced heart failure through inhibition of NADPH oxidase-derived oxidative stress

Doxorubicin (DOX), which is widely used for the treatment of cancer, induces cardiomyopathy associated with NADPH oxidase-derived reactive oxygen species. GSK2795039 is a novel small molecular NADPH oxidase 2 (Nox2) inhibitor. In this study, we investigated whether GSK2795039 prevents receptor-interacting protein kinase 1 (RIP1)-RIP3-mixed lineage kinase domain-like protein (MLKL)-mediated cardiomyocyte necroptosis in DOX-induced heart failure through NADPH oxidase inhibition. Eight-week old mice were randomly divided into 4 groups: control, GSK2795039, DOX and DOX plus GSK2795039. H9C2 cardiomyocytes were treated with DOX and GSK2795039. In DOX-treated mice, the survival rate was reduced, left ventricular (LV) end-systolic dimension was increased and LV fractional shortening was decreased, and these alterations were attenuated by the GSK2795039 treatment. GSK2795039 inhibited not only myocardial NADPH oxidase subunit gp91phox (Nox2) protein, but also p22phox, p47phox and p67phox proteins and prevented oxidative stress 8-hydroxy-2′-deoxyguanosine levels in DOX-treated mice. RIP3 protein and phosphorylated RIP1 (p-RIP1), p-RIP3 and p-MLKL proteins, reflective of their respective kinase activities, markers of necroptosis, were markedly increased in DOX-treated mice, and the increases were prevented by GSK2795039. GSK2795039 prevented the increases in serum lactate dehydrogenase and myocardial fibrosis in DOX-treated mice. Similarly, in DOX-treated cardiomyocytes, GSK2795039 improved cell viability, attenuated apoptosis and necrosis and prevented the increases in p-RIP1, p-RIP3 and p-MLKL expression. In conclusion, GSK2795039 prevents RIP1-RIP3-MLKL-mediated cardiomyocyte necroptosis through inhibition of NADPH oxidase-derived oxidative stress, leading to the improvement of myocardial remodeling and function in DOX-induced heart failure. These findings suggest that GSK2795039 may have implications for the treatment of DOX-induced cardiomyopathy.

Shenlian extract attenuates myocardial ischaemia-reperfusion injury via inhibiting M1 macrophage polarization by silencing miR-155

Context Shenlian extract (SL) is a combination of Salvia miltiorrhiza Bge. (Labiatae) and Andrographis paniculata (Burm. F.) Wall. Ex Nees (Acanthaceae) extracts, which promote blood circulation and clear endogenous heat toxins. Myocardial ischaemia-reperfusion injury (MI/RI) is aggravated myocardial tissue damage induced by reperfusion therapy after myocardial infarction. Objectives This study explores the effect of SL on MI/RI and the underlying mechanism. Materials and methods Primary peritoneal macrophages (pMACs) were treated with LPS and SL (5, 10 or 20 μg/mL) for 24 h. The myocardial ischaemia-reperfusion (MI/R) model was established after administration of different doses of SL (90, 180 or 360 mg/kg). Myocardial tissue injury was assessed by methylthiazolyl tetrazolium (TTC) staining and levels of creatine kinase (CK), lactate dehydrogenase (LDH) and superoxide dismutase (SOD) in mice. The double immunofluorescence staining of iNOS/F4/80 and CD86/F4/80 was used to detect macrophage M1 polarization. The levels of miR-155, inflammatory factors and chemokines were detected by qRT-PCR or ELISA. CD86, iNOS, SOCS3, JAK2, p-JAK2, STAT3 and p-STAT3 proteins expressions in macrophages were analyzed by western blotting. Conditioned medium transfer systems were designed to unite M1 macrophages with H/R cardiomyocytes, and cell apoptosis was detected by TUNEL staining, western blotting or immunohistochemistry. Results SL reduced apoptosis, diminished CK and LDH levels, raised SOD concentration and decreased infarct size in the MI/R model. Meanwhile, SL decreased miR-155 level, inhibited M1 macrophage polarization and inflammation. Furthermore, SL promoted SOCS3 expression and blocked JAK2/STAT3 pathway in vitro. Conclusions SL may be a promising TCM candidate for MI/RI. The underlying mechanisms could be associated with inhibition of M1 macrophage polarization via down-regulating miR-155.

Protective effects of sinomenine hydrochloride on lead-induced oxidative stress, inflammation, and apoptosis in mouse liver.

Lead, one of the most common heavy metal toxins, seriously affects the health of humans and animals. Sinomenine hydrochloride (SH) shows antioxidative, anti-inflammatory, antiviral, and anticancer properties. Hence, this study investigated the protective effects of SH against Pb-induced liver injury and explored the underlying mechanisms. First, a mouse model of lead acetate (0.5 g/L lead acetate in water, 8 weeks) was established, and SH (100 mg/kg bw in water, 8 weeks) intervention was administered by gavage. Then, the protective effect of SH against lead-induced liver injury was evaluated through serum biochemical analysis, histopathological analysis, and determination of malondialdehyde (MDA) and total antioxidant capacity (T-AOC) levels. The messenger RNA (mRNA) expression levels of the cytokines IL-1β and TNF-α and the apoptosis factors Bax, Bcl-2, and Caspase3 in the liver were detected by quantitative real-time PCR. Then, the expression levels of IL-1β and TNF-α in the liver were detected by ELISA. Immunohistochemical determination of the expression of the apoptosis factors Bax, Bcl-2, and Caspase3 was performed. SH treatment reduced the levels of liver alanine aminotransferase, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and MDA in Pb-treated mice, indicating that SH protected the liver from injury and oxidative stress in Pb-treated mice. SH also increased the liver T-AOC of Pb-treated mice. Quantitative real-time PCR, ELISA, and immunohistochemical analysis showed that SH inhibited apoptosis, as indicated by the regulation of the mRNA expression of Bax and Bcl-2 and the reduced expression of Caspase3 and pro-inflammatory factors (IL-1β and TNF-α) in the livers of Pb-treated mice. These results suggest that SH protects the mouse liver from Pb-induced injury. The underlying mechanism involves antioxidative, anti-inflammatory, and anti-apoptotic processes.

Creatinine accelerates APAP-induced liver damage by increasing oxidative stress through ROS/JNK signaling pathway.

Serum creatinine is an endogenous biomarker to estimate glomerular filtration rate (GFR) and is commonly used to assess renal function in clinical practice. Acetaminophen (APAP), the most available analgesic and antipyretic medication, is recommended as the drug of choice for pain control in patients with renal diseases. However, an overdose of APAP can lead to severe acute liver injury, which is also the most common cause of acute liver failure in western countries. The role of creatinine in APAP-induced liver injury is unclear and should be further explored. Herein, clinical data on patients with drug-induced liver injury revealed that the creatinine concentration between 82-442 μmol/L for female and 98–442 μmol/L for male is positively correlated with alanine aminotransferase (ALT), aspartate aminotransferase (AST). While there was no correlation between creatinine and ALT and AST when creatinine concentration is over 442 μmol/L. In addition, mice were administrated with creatinine intraperitoneally for 1 week before APAP injection to investigated the pathophysiological role of creatinine in APAP-induced acute liver injury. The results showed that creatinine administration aggravated hepatic necrosis and elevated serum lactate dehydrogenase (LDH) and ALT levels in mice upon APAP injection. The mechanism study demonstrated that creatinine could increase the production of reactive oxygen activation (ROS) and the activation of c-Jun N-terminal kinase (JNK). Furthermore, the liver injury was alleviated and the difference between APAP-treated mice and APAP combined with creatinine-treated mice was blunted after using specific ROS and JNK inhibitors. Significantly, creatinine stimulation aggravates APAP-induced cell death in HepaRG cells with the same mechanism. In summary, this study proposed that creatinine is closely related with liver function of drug-induced liver injury and exacerbates APAP-induced hepatocyte death by promoting ROS production and JNK activation, thus providing new insight into the usage of APAP in patients with kidney problems.

Indole-3-Carbinol (I3C) Protects the Heart From Ischemia/Reperfusion Injury by Inhibiting Oxidative Stress, Inflammation, and Cellular Apoptosis in Mice.

Strategies for treating myocardial ischemia in the clinic usually include re-canalization of the coronary arteries to restore blood supply to the myocardium. However, myocardial reperfusion insult often leads to oxidative stress and inflammation, which in turn leads to apoptosis and necrosis of myocardial cells, for which there are no standard treatment methods. The aim of this study was to determine the pharmacological effect of indole-3-carbinol (I3C), a phytochemical found in most cruciferous vegetables, in a mouse model of myocardial ischemia/reperfusion injury (MIRI). Our results showed that I3C pretreatment (100 mg/kg, once daily, i. p.) prevented the MIRI-induced increase in infarct size and serum creatine kinase (CK) and lactate dehydrogenase (LDH) in mice. I3C pretreatment also suppressed cardiac apoptosis in MIRI mice by increasing the expression levels of the anti-apoptotic protein Bcl-2 and decreasing the expression levels of several apoptotic proteins, including Bax, caspase-3, and caspase-9. In addition, I3C pretreatment was found to reduce the levels of parameters reflecting oxidative stress, such as dihydroethidium (DHE), malondialdehyde (MDA), reactive oxygen species (ROS), and nitric oxide (NO), while increasing the levels of parameters reflecting anti-oxidation, such as total antioxidant capacity (T-AOC) and glutathione (GSH), in MIRI-induced ischemic heart tissue. I3C pretreatment was also able to remarkably decrease the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) mRNA in ischemic heart tissue. These results demonstrate that administration of I3C protects the heart from MIRI through its anti-apoptotic, antioxidant, and anti-inflammatory effects.

Anti-fatigue activity of the polysaccharides isolated from Ribes stenocarpum Maxim

In the present study, the crude polysaccharides from Ribes stenocarpum Maxim. (RPs) were isolated by ultrasonic-assisted extraction. The physicochemical analysis revealed that RPs is a pyranose configuration connected by β-glycosidic bonds without three-stranded helical conformation, and is composed of mannose, ribose, glucuronic acid, galactose, glucose, arabinose, galacturonic acid, and xylose with a molecular weight of 44,200 Da. Furthermore, the animal experimental results demonstrated that RPs could significantly prolong the forced swimming time of mice, increase the liver glycogen and muscle glycogen levels, up-regulate the activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in mice, and reduce the blood urea nitrogen (BUN), lactic acid (LD), and malondialdehyde (MDA) contents. The above results suggested that RPs could effectively reduce the oxidative stress response of mice during strenuous exercise and exert significant anti-fatigue activity.

Arginine promotes skeletal muscle fiber type transformation from fast-twitch to slow-twitch via Sirt1/AMPK pathway

This study investigated the effect of arginine on skeletal muscle fiber type transformation in mice and in C2C12 myotubes. Our data showed that dietary supplementation of arginine in mice significantly up-regulated the slow myosin heavy chain (MyHC), troponin I-SS, sirtuin1 (Sirt1) and peroxisome proliferator activated receptor-γ coactivator-1α (PGC-1α) protein expressions, as well as significantly down-regulated the fast MyHC protein expression. In C2C12 myotubes, arginine significantly increased the protein level of slow MyHC and the number of slow MyHC-positive cells, as well as significantly decreased the protein level of fast MyHC and the number of fast MyHC-positive cells. We also showed that arginine increased the activities of succinic dehydrogenase and malate dehydrogenase and decreased the activity of lactate dehydrogenase in mice and in C2C12 myotubes. Here we found that AMP-activated protein kinase (AMPK) was activated by arginine in mice and in C2C12 myotubes. However, inhibition of AMPK activity by compound C significantly attenuated the effects of arginine on slow MyHC and fast MyHC expressions in C2C12 myotubes. Finally, we showed that inhibition of Sirt1 expression by EX527 attenuated arginine-induced increase in the protein levels of phospho-AMPK and slow MyHC, the mRNA level of nitric oxide synthase (NOS) and the contents of NOS and NO, as well as decrease in fast MyHC protein level. Together, our findings indicated that arginine promotes skeletal muscle fiber type switching from fast-twitch to slow-twitch via Sirt1/AMPK pathway.

Phthaloyl modification of a polysaccharide from Lachnum YM262 and immunomodulatory activity

The phthaloyl polysaccharide (PHEP-2a) was prepared from a Lachnum exopolysaccharide (LEP-2a) by chemical modification, with a degree of substitution of 0.251. The results of UV, FT-IR, 1H NMR and 13C NMR analysis indicated that phthaloyl modification of polysaccharide was successful. Moreover, both elemental contents and thermal properties of the polysaccharide were changed after phthaloyl modification. Immunomodulatory activity evaluation revealed that compared with negative control group, LEP-2a and its derivative at high dose could remarkably increase the body weight, organ indexes, phagocytic index and half hemolysis value, promote splenocytes proliferation activity, improve the production of serum cytokines, such as interleukin-2 and tumor necrosis factor-alpha (TNF-α), and enhance the activities of acid phosphatase and lactate dehydrogenase in cyclophosphamide-treated mice. They could also enhance the contents of T-SOD and GSH-Px while decrease MDA levels in cyclophosphamide-treated mice. Furthermore, PHEP-2a showed more significant effects than LEP-2a at the same dosage, indicating that phthaloyl modification was an effective way to enhance the immunomodulatory activity of the polysaccharide.

Protective effects of ghrelin against oxidative stress, inducible nitric oxide synthase and inflammation in a mouse model of myocardial ischemia/reperfusion injury via the HMGB1 and TLR4/NF-κB pathway.

The present study aimed to investigate the protective effects of ghrelin against oxidative stress, inducible nitric oxide synthase (iNOS) and inflammation in a mouse model of myocardial ischemia/reperfusion injury (MIRI). In addition, the study aimed to determine its underlying mechanisms. A mouse model of MIRI was used invivo, in order to ascertain the protective effects of ghrelin on MIRI. Commercial kits were used to measure the serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) in MIRI mice. Furthermore, Evan's Blue-triphenyltetrazolium chloride solution was used to analyze the protective effects of ghrelin against infarct size in MIRI mice. The underlying mechanisms were determined by measuring MIRI-induced tumor necrosis factor (TNF)‑α, interleukin (IL)‑6, superoxide dismutase (SOD), glutathione (GSH), GSH-peroxidase (GSH‑PX), malondialdehyde (MDA) and caspase‑3/caspase‑9 activities, and iNOS, high mobility group box1 (HMGB1), Toll‑like receptor4 (TLR4) and nuclear factor (NF)‑κB protein expression in MIRI mice. The results demonstrated that MIRI led to an increase in infarct size; CK, LDH, TNF‑α, IL‑6, MDA, caspase‑3 and caspase-9 serum levels; and iNOS protein expression. MIRI resulted in inhibition of SOD, FSH and GSH‑PX levels. Conversely, these alterations were significantly inhibited following treatment with ghrelin. In addition, the protective effects of ghrelin against MIRI suppressed HMGB1, TLR4 and NF‑κB protein expression in MIRI mice. The present study revealed that ghrelin exerted protective effects against oxidative stress, iNOS and inflammation in MIRI mice via the HMGB1/TLR4/NF-κB pathway.

Ado-Trastuzumab Emtansine Targets Hepatocytes Via Human Epidermal Growth Factor Receptor 2 to Induce Hepatotoxicity.

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate (ADC) approved for the treatment of HER2-positive metastatic breast cancer. It consists of trastuzumab, a humanized mAb directed against HER2, and a microtubule inhibitor, DM1, conjugated to trastuzumab via a thioether linker. Hepatotoxicity is one of the serious adverse events associated with T-DM1 therapy. Mechanisms underlying T-DM1-induced hepatotoxicity remain elusive. Here, we use hepatocytes and mouse models to investigate the mechanisms of T-DM1-induced hepatotoxicity. We show that T-DM1 is internalized upon binding to cell surface HER2 and is colocalized with LAMP1, resulting in DM1-associated cytotoxicity, including disorganized microtubules, nuclear fragmentation/multiple nuclei, and cell growth inhibition. We further demonstrate that T-DM1 treatment significantly increases the serum levels of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase in mice and induces inflammation and necrosis in liver tissues, and that T-DM1-induced hepatotoxicity is dose dependent. Moreover, the gene expression of TNFα in liver tissues is significantly increased in mice treated with T-DM1 as compared with those treated with trastuzumab or vehicle. We propose that T-DM1-induced upregulation of TNFα enhances the liver injury that may be initially caused by DM1-mediated intracellular damage. Our proposal is underscored by the fact that T-DM1 induces the outer mitochondrial membrane rupture, a typical morphologic change in the mitochondrial-dependent apoptosis, and mitochondrial membrane potential dysfunction. Our work provides mechanistic insights into T-DM1-induced hepatotoxicity, which may yield novel strategies to manage liver injury induced by T-DM1 or other ADCs.

Ferulic Acid against Cyclophosphamide-Induced Heart Toxicity in Mice by Inhibiting NF-κB Pathway.

The purpose of the present study was to elucidate the protective effects of ferulic acid (FA) against cyclophosphamide- (CTX-) induced changes in mice. Forty-eight male ICR mice were divided into four groups. Control group was intraperitoneally (i.p.) injected with 200 μL of phosphate buffer saline (PBS). Model group was intraperitoneally injected with a single dose of CTX (200 mg/kg). FA (50 mg/kg) and FA (100 mg/kg) groups were intraperitoneally injected with a single dose of CTX (200 mg/kg) followed by the intragastric treatment with FA (50, 100 mg/kg) for 7 consecutive days. After 12 d, the mice were sacrificed to analyze the hematological, biochemical, histological parameters and mechanism research. The results indicated that FA significantly decreased the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), lactate dehydrogenase (LDH), interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α) in CTX-injected mice. In addition, FA effectively reduced the total numbers of white blood cells (WBCs), red blood cells, platelets, and hemoglobin content. FA also obviously attenuated the histological changes of the heart tissues caused by CTX. Moreover, Western blot demonstrated that FA inhibited the phosphorylations of NF-κB signaling pathway in CTX-stimulated cardiac tissues. In conclusion, FA might be considered as an effective agent in the amelioration of the heart toxicity resulting from CTX treatment.

Expression of Lactate Dehydrogenase in Aspergillus niger for L-Lactic Acid Production.

Different engineered organisms have been used to produce L-lactate. Poor yields of lactate at low pH and expensive downstream processing remain as bottlenecks. Aspergillus niger is a prolific citrate producer and a remarkably acid tolerant fungus. Neither a functional lactate dehydrogenase (LDH) from nor lactate production by A. niger is reported. Its genome was also investigated for the presence of a functional ldh. The endogenous A. niger citrate synthase promoter relevant to A. niger acidogenic metabolism was employed to drive constitutive expression of mouse lactate dehydrogenase (mldhA). An appraisal of different branches of the A. niger pyruvate node guided the choice of mldhA for heterologous expression. A high copy number transformant C12 strain, displaying highest LDH specific activity, was analyzed under different growth conditions. The C12 strain produced 7.7 g/l of extracellular L-lactate from 60 g/l of glucose, in non-neutralizing minimal media. Significantly, lactate and citrate accumulated under two different growth conditions. Already an established acidogenic platform, A. niger now promises to be a valuable host for lactate production.

Combination of glycosphingosomes and liposomal doxorubicin shows increased activity against dimethyl-α-benzanthracene-induced fibrosarcoma in mice.

The present study aimed to assess the antitumor effect of glycosphingolipid-incorporated liposomes (glycosphingosomes) in combination with liposomal doxorubicin (Lip-Dox) in a mouse model of fibrosarcoma. Glycosphingosomes were prepared by incorporating glycosphingolipids isolated from Sphingomonas paucimobilis into the liposomes of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, cholesterol, and cardiolipin. Tumors were induced by administering dimethyl-α-benzanthracene, and tumor-bearing mice were treated with various formulations of Dox, including free Dox, Lip-Dox, or glycosphingosomes + Lip-Dox. Mice were observed for 90 days to monitor their survival and tumor size. Free Dox, but not Lip-Dox or a combination of glycosphingosomes and Lip-Dox, caused the substantial depletion of leukocytes and significantly increased the levels of lactate dehydrogenase and creatinine kinase in mice. Tumor-bearing mice treated with a combination of glycosphingosomes and Lip-Dox showed restricted tumor growth and increased survival when compared to those treated with free Dox or Lip-Dox. The results of the present study suggest that a combination of glycosphingosomes and Lip-Dox may prove to be very effective in the treatment of tumors.

Anti-Fatigue Effects of Fermented Rhodiola rosea Extract in Mice.

Rhodiola rosea is a perennial plant which grows in the alpine regions of Europe and Asia. Although the protective effects of R. rosea extract from fatigue due to exercise stress have been reported, studies on fermented R. rosea extract remain insufficient to date. Therefore, this study was conducted to examine the protective effects of fermented R. rosea extract against fatigue and exercise stress. As a result, fermented R. rosea extract was found to significantly increase swimming time, hepatic superoxide dismutase content, and serum lactate dehydrogenase in mice, while decreasing serum blood urea nitrogen content compared to R. rosea extract. Given the above results, it is considered that fermented R. rosea extract effectively protects against fatigue caused by strenuous exercise.

Low doses of ethanolic extract of Boldo (Peumus boldus) can ameliorate toxicity generated by cisplatin in normal liver cells of mice in vivo and in WRL-68 cells in vitro, but not in cancer cells in vivo or in vitro

Use of cisplatin, a conventional anticancer drug, is restricted because it generates strong hepatotoxicity by accumulating in liver. Therefore its anticancer potential can only be fully exploited if its own toxicity is considerably reduced. Towards this goal, ethanolic extract of the plant, Boldo (Peumus boldus), known for its antihepatotoxic effects, was used simultaneously with cisplatin, to test its ability to reduce cisplatin's cytotoxicity without affecting its anticancer potential. The cytotoxicity of Boldo extract (BE) and cisplatin, administered alone and in combination, was determined in three cancer cell lines (A549, HeLa, and HepG2) and in normal liver cells (WRL-68). Drug-DNA interaction, DNA damage, cell cycle, apoptosis, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP, ΔΨ) were also studied. Hepatotoxicity and antioxidant activity levels were determined by alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and glutathione assays in mice. The cytotoxicity of related proteins was tested by Western blotting. Co-administration of BE and cisplatin increased viability of normal cells, but had no effect on the viability of cancer cells. Boldo protected liver from damage and normalized different antioxidant enzyme levels in vivo and also reduced ROS and re-polarized MMP in vitro. Bax and cytochrome c translocation was reduced with caspase 3 down-regulation. Further, a drug-DNA interaction study revealed that BE reduced cisplatin's DNA-binding capacity, resulting in a reduction in DNA damage. Results indicated that a low dose of BE could be used beneficially in combination with cisplatin to reduce its toxicity without hampering cisplatin's anticancer effect. These findings signify a potential future use of BE in cancer therapy.

Mouse lactate dehydrogenase X: A promising magnetic resonance reporter protein using hyperpolarized pyruvic acid derivative Y

We developed a promising candidate for a hypersensitive magnetic resonance (MR) reporter protein. The reporter protein is comprised of mouse lactate dehydrogenase-X (mLDH-X) and a hyperpolarized pyruvic acid derivative, substrate Y that gives no false-positive signals by endogenous human lactate dehydrogenases (hLDHs). The X–Y pair shows high MR sensitivity and sufficient reaction kinetics, thus enabling direct detection of reporter protein X in crude biological mixtures by monitoring the 13C NMR signal of hyperpolarized product Yr.

Effect of Terminalia arjuna on antioxidant defense system in cancer

Constant production of reactive oxygen species (ROS) during aerobic metabolism is balanced by antioxidant defense system of an organism. Although low level of ROS is important for various physiological functions, its accumulation has been implicated in the pathogenesis of age-related diseases such as cancer and coronary heart disease and neurodegenerative disorders such as Alzheimer's disease. It is generally assumed that frequent consumption of phytochemicals derived from vegetables, fruits, tea and herbs may contribute to shift the balance towards an adequate antioxidant status. The present study is aimed to investigate the effect of aqueous extract of medicinal plant Terminalia arjuna on antioxidant defense system in lymphoma bearing AKR mice. Antioxidant action of T. arjuna is monitored by the activities of catalase, superoxide dismutase and glutathione S transferase which constitute major antioxidant defense system by scavenging ROS. These enzyme activities are low in lymphoma bearing mice indicating impaired antioxidant defense system. Oral administration of different doses of aqueous extract of T. arjuna causes significant elevation in the activities of catalase, superoxide dismutase and glutathione S transferase. T. arjuna is found to down regulate anaerobic metabolism by inhibiting the activity of lactate dehydrogenase in lymphoma bearing mice, which was elevated in untreated cancerous mice. The results indicate the antioxidant action of aqueous extract of T. arjuna, which may play a role in the anti carcinogenic activity by reducing the oxidative stress along with inhibition of anaerobic metabolism.

Expression of the Gene for Mouse Lactate Dehydrogenase C (Ldhc) Is Required for Male Fertility1

The lactate dehydrogenase (LDH) protein family members characteristically are distributed in tissue- and cell type-specific patterns and serve as the terminal enzyme of glycolysis, catalyzing reversible oxidation reduction between pyruvate and lactate. They are present as tetramers, and one family member, LDHC, is abundant in spermatocytes, spermatids, and sperm, but also is found in modest amounts in oocytes. We disrupted the Ldhc gene to determine whether LDHC is required for spermatogenesis, oogenesis, and/or sperm and egg function. The targeted disruption of Ldhc severely impaired fertility in male Ldhc(-/-) mice but not in female Ldhc(-/-) mice. Testis and sperm morphology and sperm production appeared to be normal. However, total LDH enzymatic activity was considerably lower in Ldhc(-/-) sperm than in wild type sperm, indicating that the LDHC homotetramer (LDH-C(4)) is responsible for most of the LDH activity in sperm. Although initially motile when isolated, there was a more rapid reduction in the level of ATP and in motility in Ldhc(-)(/-) sperm than in wild-type sperm. Moreover, Ldhc(-/-) sperm did not acquire hyperactivated motility, were unable to penetrate the zona pellucida in vitro, and failed to undergo the phosphorylation events characteristic of capacitation. These studies showed that LDHC plays an essential role in maintenance of the processes of glycolysis and ATP production in the flagellum that are required for male fertility and sperm function.

Role of CYP2E1 in thioacetamide-induced mouse hepatotoxicity

Previous experiments showed that treatment of mice and rats with thioacetamide (TAA) induced liver cell damage, fibrosis and/or cirrhosis, associated with increased oxidative stress and activation of hepatic stellate cells. Some experiments suggest that CYP2E1 may be involved in the metabolic activation of TAA. However, there is no direct evidence on the role of CYP2E1 in TAA-mediated hepatotoxicity. To clarify this, TAA-induced hepatotoxicity was investigated using Cyp2e1-null mice. Male wild-type and Cyp2e1-null mice were treated with TAA (200 mg/kg of body weight, single, i.p.) at 6 weeks of age, and hepatotoxicity examined 24 and 48 h after TAA treatment. Relative liver weights of Cyp2e1-null mice were significantly different at 24 h compared to wild-type mice ( p < 0.01). Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in Cyp2e1-null mice were significantly different at both time points compared to wild-type mice ( p < 0.01). Histopathological examination showed Cyp2e1-null mice represented no hepatototoxic lesions, in clear contrast to severe centriobular necrosis, inflammation and hemorrhage at both time points in wild-type mice. Marked lipid peroxidation was also only limited to wild-type mice ( p < 0.01). Similarly, TNF-α, IL-6 and glutathione peroxidase mRNA expression in Cyp2e1-null mice did not significantly differ from the control levels, contrasting with the marked alteration in wild-type mice ( p < 0.01). Western blot analysis further revealed no increase in iNOS expression in Cyp2e1-null mice. These results reveal that CYP2E1 mediates TAA-induced hepatotoxicity in wild-type mice as a result of increased oxidative stress.