Synergistic effects of Rapamycin and Fluorouracil to treat a gastric tumor in a PTEN conditional deletion mouse model.

The tumor suppressor gene phosphatase and tensin homolog (PTEN) in PI3K/Akt/mTOR pathway is essential in inhibiting tumor growth and metastasis. However, whether the mutation of PTEN gene could induce tumorigenesis and impact the treatment of gastric cancer is still unclear. The purpose of the study was to investigate the combined treatment of gastric tumorigenesis using Rapamycin and Fluorouracil (5-Fu) through interfering with the Akt/mTOR pathway in a mouse model with PTEN conditional deletion.

Atorvastatin induces mitochondrial dysfunction and cell apoptosis in HepG2 cells via inhibition of the Nrf2 pathway.

Atorvastatin (ATO) is a 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor widely used to treat hypercholesterolemia. However, clinical application is limited by potential hepatotoxicity. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a master regulator of cellular antioxidants, and oxidative stress is implicated in statin-induced liver injury.

Subchronic Oral Toxicity Evaluation of Lanthanum: A 90-day, Repeated Dose Study in Rats.

Objective: The present study was undertaken to evaluate the subchronic toxicity of lanthanum and to determine the no observed adverse effect level (NOAEL), which is a critical factor in the establishment of an acceptable dietary intake (ADI).

Methods: In accordance with the Organization for Economic Co-operation and Development (OECD) testing guidelines, lanthanum nitrate was administered once daily by gavage to Sprague-Dawley (SD) rats at dose levels of 0, 1.5, 6.

PM obtained from urban areas in Beijing induces apoptosis by activating nuclear factor-kappa B.

Background: Particulate matter (PM), which has adverse effects on citizen health, is a major air pollutant in Beijing city. PM is an indicator of PM in urban areas and can cause serious damage to human health. Many epidemiological studies have shown that nuclear factor-kappa B (NF-κB) is involved in PM-induced cell injury, but the exact mechanisms are not well understood.

Subchronic toxicity study of yttrium nitrate by 90-day repeated oral exposure in rats.

Concerns regarding the adverse effects of long-term exposure to low levels of rare earth elements (REEs) from foods on human health have arisen in recent years. Nevertheless, no official acceptable daily intake (ADI) has yet been proposed for either total REEs or individual REE. In accordance with the Organization for Economic Co-operation and Development (OECD) testing guideline, the present study was undertaken to evaluate the subchronic toxicity of yttrium, a representative heavy REE with higher contaminated level in foods in China, to achieve a no observed adverse effect level (NOAEL) which is a critical basis for the establishment of an ADI.

AMPK activator acadesine fails to alleviate isoniazid-caused mitochondrial instability in HepG2 cells.

Isoniazid (INH) is a first-line antituberculosis drug that is adversely associated with hepatotoxicity. Recently, impairment of mitochondrial homeostasis involved in this side effect has been noticed. Mitochondrial homeostasis is achieved by the balance between the generation of functional mitochondria by biogenesis and elimination of dysfunctional mitochondria by autophagy.

Silica nanoparticles and lead acetate co-exposure triggered synergistic cytotoxicity in A549 cells through potentiation of mitochondria-dependent apoptosis induction.

The adverse effects of PM2.5 are the results of combined toxicities of finer particles and their adsorbed toxic pollutants. Nevertheless, the combined toxicity of finer particles and air pollutants still remains unclear.

Metallothionein protects against isoniazid-induced liver injury through the inhibition of CYP2E1-dependent oxidative and nitrosative impairment in mice.

Oxidative stress mediated by hepatic CYP2E1 during isoniazid (INH) metabolism is considered responsible for INH hepatotoxicity. This study attempts to determine whether metallothionein (MT), a cysteine-rich antioxidant can protect against INH-induced liver injury by using a MT-I/II deficient mouse model (MT-/- mice). MT-/- mice and the corresponding wild-type mice received intragastric administrations of 0, 75, 150 and 300 mg/kg of INH for 15 days.

Prepubertal exposure to an oestrogenic mycotoxin zearalenone induces central precocious puberty in immature female rats through the mechanism of premature activation of hypothalamic kisspeptin-GPR54 signaling.

Sporadic epidemics and several researches in rodents indicated that zearalenone (ZEA) and its metabolites, the prevailing oestrogenic mycotoxins in foodstuffs, were a triggering factor for true precocious puberty development in girls. Nevertheless, the neuroendocrine mechanism through which ZEA mycoestrogens advance puberty onset is not fully understood. To elucidate this issue, hypothalamic kisspeptin-G-protein coupled receptor-54 (GPR54) signaling pathway that regulates the onset of puberty was focused on in the present study.

Induction of protective autophagy against apoptosis in HepG2 cells by isoniazid independent of the p38 signaling pathway.

Isoniazid (INH), one of the first-line anti-tuberculosis drugs, is adversely associated with hepatotoxicity in the clinic. However, the detailed mechanism of this side effect is still unclear. The traditional theory that cytochrome P450 2E1 is involved in INH-induced hepatotoxicity remains controversial, therefore other mechanisms by which INH exerts hepatotoxicity need to be investigated.

Delay of the onset of puberty in female rats by prepubertal exposure to T-2 toxin.

Growing evidence has revealed the deleterious influence of environmental and food contaminants on puberty onset and development in both animals and children, provoking an increasing health concern. T-2 toxin, a naturally-produced Type A trichothecene mycotoxin which is frequently found in cereal grains and products intended for human and animal consumption, has been shown to impair the reproduction and development in animals. Nevertheless, whether this trichothecene mycotoxin can disturb the onset of puberty in females remains unclear.

Lessons from Toxicology: Developing a 21st-Century Paradigm for Medical Research.

Biomedical developments in the 21st century provide an unprecedented opportunity to gain a dynamic systems-level and human-specific understanding of the causes and pathophysiologies of disease. This understanding is a vital need, in view of continuing failures in health research, drug discovery, and clinical translation. The full potential of advanced approaches may not be achieved within a 20th-century conceptual framework dominated by animal models.

Combined exposure to nano-silica and lead induced potentiation of oxidative stress and DNA damage in human lung epithelial cells.

Growing evidence has confirmed that exposure to ambient particulate matters (PM) is associated with increased morbidity and mortality of cardiovascular and pulmonary diseases. Ambient PM is a complex mixture of particles and air pollutants. Harmful effects of PM are specifically associated with ultrafine particles (UFPs) that can adsorb high concentrations of toxic air pollutants and are easily inhaled into the lungs.

Metallothioneins attenuate paraquat-induced acute lung injury in mice through the mechanisms of anti-oxidation and anti-apoptosis.

Paraquat (PQ) is a widely used herbicide, and lung is the primary target of PQ poisoning. Metallothionein (MT) is a potent antioxidant and free radical scavenger, and has been shown to play a protective role in lung injury induced by different stressors. This study was undertaken to evaluate the protective potential of MT against PQ-induced acute lung injury using MT-I/II null (MT(-/-)) mice.

[Development of human embryonic stem cell model for toxicity evaluation].

The current international standard for toxicity screening of biomedical devices and materials recommend the use of immortalized cell lines because of their homogeneous morphologies and infinite proliferation which provide good reproducibility for in vitro cytotoxicity screening. However, most of the widely used immortalized cell lines are derived from animals and may not be representative of normal human cell behavior in vivo, in particular in terms of the cytotoxic and genotoxic response. Therefore, It is vital to develop a model for toxicity evaluation.

T-2 toxin induces apoptosis in ovarian granulosa cells of rats through reactive oxygen species-mediated mitochondrial pathway.

Objective: To investigate the reproductive toxicity and cytotoxicity of T-2 toxin, which is a mycotoxin, and to explore its potential apoptotic induction mechanism.

Methods: Ovarian granulosa cells of rats were treated with T-2 toxin (1-100nM) for 24h. The cytotoxicity was assessed with MTT bioassay; apoptotic cells were identified microscopically by chromatin condensation and nuclear fragmentation with Hoechst 33258; mitochondrial membrane potential with hodamine 123 and reactive reactive oxygen species (ROS) with 2',7'-dichlorofluoresceinacetate (DCFH-DA) was analyzed by fluorometry; p53 and other apoptosis-related proteins such as Bax, Bcl-2, caspase-3, caspase-9 were determined by Western blot analysis, and related mRNA expressions were determined by reverse transcriptase-polymerase chain reaction (RT-PCR).

[Effects of metallothionein on rifampicin (RFP)-induced hepatotoxicity in mice].

Objective: To investigate the effect of metallothionein (MT) on rifampicin (RFP)-induced hepatotoxicity and the possible mechanisms.

Methods: Male MT- I / II null (MT-/-) and wild type (MT+/+) mice were randomly divided into 4 groups, respectively, and were orally administered RFP (50, 100 or 200 mg/kg) or equal volumes of solvent daily for 15 consecutive days. Levels of plasma alanine aminotransferase (ALT), alkaline phosphatase (ALP) and direct bilirubin (DB) were determined.

Metallothionein-I/II null cardiomyocytes are sensitive to Fusarium mycotoxin butenolide-induced cytotoxicity and oxidative DNA damage.

Previous studies revealed butenolide (BUT), a Fusarium mycotoxin distributes extensively, induced myocardial oxidative damage, which could be abated by antioxidants such as glutathione. Metallothionein (MT) has proved to attenuate several oxidative cardiomyopathies via its potent antioxidant property. The present study is therefore undertaken to investigate the protective potential of the endogenous expression of MT against BUT-induced myocardial toxicity.

Chlorpyrifos induces delayed cytotoxicity after withdrawal in primary hippocampal neurons through extracellular signal-regulated kinase inhibition.

In this study, the delayed effect and related mechanism after chlorpyrifos (CPF) withdrawal was studied in primary rat hippocampal neurons. The results showed that 10 muM CPF induced no detectable cytotoxicity during 96 h continuous exposure while its withdrawal after 48 h exposure induced evident cytotoxicity, as indexed by decreased methyl thiazolyl tetrazolium (MTT) metabolism, increased loss of neurons immunostained by neuron-specific enolase (NSE) antibody, and the increased terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) positive cell rate in the following 24 h and 48 h incubation in the absence of CPF. Extracellular signal-related kinase (ERK)1/2 activation by phosphorylation was observed and persisted during CPF exposure.

Effects of Fusarium mycotoxin butenolide on myocardial mitochondria in vitro.

Fusarium mycotoxin toxicosis has been implicated in the etiology of Keshan disease, an endemic mitochondrial cardiomyopathy prevailing in certain areas of China. Butenolide (4-acetamido-4-hydroxy-2-butenoic acid gamma-lactone) is one of the Fusarium mycotoxins which are frequently detected from cereal grains in endemic areas. A recent study indicates that this mycotoxin induces rat cardiotoxicity, but its effect on the myocardial mitochondria remains unclear.

[Nephrotoxicity study of Aristolochia fangchi in rats by metabonomics].

Objective: To study the changes of metabolites in rat urine after treatment of Aristolochia fangchi decoction by metabonomic method.

Methods: Sixty-four male SD rats were divided into Aristolochia fangchi group and normal control group. Rats in the Aristolochia fangchi group were orally administered with 8.

[Gene expression profile of isoniazid liver-injured rat using cDNA microarray].

Objective: To investigate the changes of gene expression profile of rat liver tissue by cDNA microarrays.

Methods: Twenty Wistar rats in control group (n = 10) and isoniazid (INH) group (n = 10) were orally administrated with normal saline and 400 mg/kg INH for 14 days, respectively. The differentially expressed genes significantly correlated with liver injury were screened and analyzed.