In recent years there have been more widely and deeply studies in investigating melamine toxicity. Generally, it is believed that the main target of melamine is the urinary system. However, previous studies revealed that it also had additional biological actions. Obviously, the toxicity mechanisms of melamine have not been fully clarified. It is well known that fetus and infant periods play the most fundamental role in the brain development. And melamine can pass through the placental and blood-brain barrier, and then exerts toxic effects on the central nervous system. This article reviewed the reports about the topic in recent years, for better understanding the dangers of melamine to infants and providing experimental data for further study.
Animals ; Blood-Brain Barrier ; drug effects ; Brain ; growth & development ; Central Nervous System ; drug effects ; Cognition ; drug effects ; Female ; Humans ; Maternal-Fetal Exchange ; drug effects ; Pregnancy ; Triazines ; pharmacokinetics ; toxicity

S100A8, an important member of the S100 protein family, is a low-molecular-weight (10.8 kDa) calcium-binding protein containing conserved EF-hand structural motifs. Previous studies have shown that the biological function of S100A8 protein is associated with a variety of inflammatory diseases, for example asthma. S100A8 protein plays important roles in the regulation of inflammation. It can activate inflammatory cells and cytokines via chemotactic activity for neutrophils, and bind to the receptor for advanced glycation end products (RAGE) and Toll-like receptor 4 (TLR4), thus mediating intracellular inflammatory signaling transduction. Additionally, recent studies have reported the anti-inflammation activity of S100A8 protein, which indicates that S100A8 may have a more complex function of biological regulation in the different pathophysiological conditions. In this review, we summarized the studies on the functions and molecular mechanisms of S100A8 protein in inflammation, which would propose a novel strategy for the prophylaxis and treatment of asthma and other inflammatory diseases.
Animals ; Asthma ; physiopathology ; Calgranulin A ; physiology ; Humans ; Inflammation ; physiopathology

The axon guidance molecule Slit is a secreted glucoprotein which is conserved during evolution. Slit has been implicated in regulating a variety of life activities, such as axon guidance, neuronal migration, neuronal morphological differentiation, tumor metastasis, angiogenesis and heart morphogenesis. Slit function mainly depends on the binding of its LRR-2 domain to the Ig1 domain of Roundabout (Robo) receptor, meanwhile Slit function is also mediated by a range of signaling molecules, including the heparan sulfate proteoglycans (HSPGs), GTPase-activating proteins (GAPs), tyrosine kinase Abelson, calcium ions, MicroRNA-218 and other axon guidance molecules. Several transcription factors, including Single-minded, Irx and Midline, were shown to regulate slit expression. In addition, multiple Slit isoforms exist as a consequence of alternative spliced transcripts. The research on guidance mechanism of Slit will facilitate the understanding of molecular mechanism underlying neural networks formation in the process of neural development and regeneration. Meanwhile, the studying of Slit guidance mechanism could promote the prevention and treatment of human neurological diseases and cancer metastasis.
Animals ; Axons ; metabolism ; physiology ; Cell Movement ; physiology ; Drosophila Proteins ; physiology ; Gene Expression Regulation ; Humans ; Intercellular Signaling Peptides and Proteins ; genetics ; physiology ; Nerve Tissue Proteins ; genetics ; metabolism ; physiology ; Neurons ; cytology ; Receptors, Immunologic ; metabolism

The aim of the present study was to investigate whether protein kinase C (PKC) was involved in the effect of mesenteric lymph duct ligation or mesenteric lymph drainage on vascular calcium sensitivity in hemorrhagic shock rats. Male Wistar rats were randomly divided into Sham, Shock (hemorrhagic shock), Shock+Ligation (mesenteric lymph duct ligation plus shock) and Shock+Drainage (mesenteric lymph drainage plus shock) groups. After being in shock (hypotension 40 mmHg) for 3 h, the tissue of superior mesenteric artery (SMA) was taken out for detecting the PKC expression and phospho-PKC (p-PKC) activity, and the vascular rings of SMA were prepared and used to measure the response to gradient calcium concentration for assaying the calcium sensitivity, the parameters of which including tension, maximum tension (E(max)) and negative logarithm of EC(50), called the pD(2). Other vascular rings from Shock+Ligation and Shock+Drainage groups were incubated with PKC regulator PMA or Staurosporine before the measurement of calcium sensitivity. The results showed that, PKC expression, p-PKC activity and calcium sensitivity of SMA in Shock group was significantly lower than that of Sham group, whereas the above-mentioned indexes were significantly elevated in Shock+Ligation and Shock+Drainage groups compared with those in Shock group. PKC agonist PMA enhanced the contractile activity of vascular rings to gradient calcium ions, and increased E(max) of SMA in Shock+Ligation and Shock+Drainage groups. On the contrary, PKC inhibitor Staurosporine significantly decreased the response to gradient calcium ions and E(max) of SMA in Shock+Ligation and Shock+Drainage groups. These results suggest that PKC plays a role in the improvement of vascular calcium sensitivity by blockade of mesenteric lymph return in hemorrhagic shock rats.
Animals ; Calcium ; pharmacology ; Drainage ; Ligation ; Lymph ; physiology ; Lymphatic Vessels ; physiology ; Male ; Mesenteric Artery, Superior ; drug effects ; physiology ; Mesentery ; Muscle, Smooth, Vascular ; drug effects ; metabolism ; Protein Kinase C ; metabolism ; physiology ; Rats ; Rats, Wistar ; Shock, Hemorrhagic ; physiopathology ; Vasoconstriction ; drug effects ; physiology

The aim of the present study was to investigate the involvements of insulin-like growth factor-1 (IGF-1) and estrogen receptor α (ERα) in the inhibitory effect of wogonin on the breast adenocarcinoma growth. Moreover, the effect of wogonin on the angiogenesis of chick chorioallantoic membrane (CAM) was also investigated. MCF-7 cells (human breast adenocarcinoma cell line) were subjected to several drugs, including IGF-1, wogonin and ER inhibitor ICI182780, alone or in combination. MTT assay was used to detect breast cancer proliferation. Western blot was used to analyze ERα and p-Akt expression levels. CAM models prepared from 6-day chicken eggs were employed to evaluate angiogenesis inhibition. The results showed wogonin and ICI182780 both exhibited a potent ability to blunt IGF-1-stimulated MCF-7 cell growth. Either of wogonin and ICI182780 significantly inhibited ERα and p-Akt expressions in IGF-1-treated cells. The inhibitory effect of wogonin showed no difference from that of ICI182780 on IGF-1-stimulated expressions of ERα and p-Akt. Meanwhile, wogonin at different concentrations showed significant inhibitory effect on CAM angiogenesis. These results suggest the inhibitory effect of wogonin on breast adenocarcinoma growth via inhibiting IGF-1-mediated PI3K-Akt pathway and regulating ERα expression. Furthermore, wogonin has a strong anti-angiogenic effect on CAM model.
Adenocarcinoma ; metabolism ; pathology ; Angiogenesis Inhibitors ; pharmacology ; Animals ; Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Chick Embryo ; Chorioallantoic Membrane ; blood supply ; Estrogen Receptor alpha ; genetics ; metabolism ; Female ; Flavanones ; pharmacology ; Humans ; Insulin-Like Growth Factor I ; antagonists & inhibitors ; pharmacology ; Scutellaria ; chemistry

The purpose of this study was to investigate the protective effect of puerarin on retina pigment epithelial (RPE) cells of diabetic rats against apoptosis. One hundred and eight Sprague-Dawley (SD) rats were randomly divided into 3 groups: control group, streptozotocin (STZ) group and puerarin group. STZ and puerarin groups received 3 d of STZ injection (45 mg/kg per day, i.p.). Additionally, puerarin groups were treated with puerarin (140 mg/kg, i.p.) from the 4th day to the end of experiment. The rats from different groups were sacrificed on 20, 40 and 60 d after STZ injection for harvesting RPE cells. Western blot analysis, DNA laddering, RT-PCR and immunohistochemistry were used for determining the expression of nitrotyrosine (NT, the foot print of peroxynitrite), cell apoptosis, iNOS mRNA and Fas/Fas ligand (FasL) signal transduction in RPE cells, respectively. The results showed that control group maintained low apoptosis level and little NT, iNOS mRNA, Fas/FasL protein expressions, as well as normal blood glucose and body weight during 60 d of the experiment. Compared with control group, STZ group showed obvious apoptosis and higher NT, iNOS mRNA, Fas/FasL protein expressions from 20 d after STZ injection. Puerarin relieved apoptosis of RPE cells and decreased NT, iNOS mRNA, Fas/FasL protein expressions in puerarin group 20 or 40 d after STZ injection, compared with STZ group. These results suggest puerarin can decrease RPE cells apoptosis in diabetic rats by reducing peroxynitrite level and iNOS expression, thus being a potential therapeutic agent in controlling of diabetic retinopathy.
Animals ; Apoptosis ; drug effects ; Diabetes Mellitus, Experimental ; metabolism ; pathology ; Diabetic Retinopathy ; prevention & control ; Fas Ligand Protein ; metabolism ; Isoflavones ; pharmacology ; Male ; Nitric Oxide Synthase Type II ; genetics ; metabolism ; Peroxynitrous Acid ; metabolism ; Protective Agents ; pharmacology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Retinal Pigment Epithelium ; pathology ; fas Receptor ; metabolism

The present study was aimed to explore the changes of phosphorylated AMP-activated protein kinase (pAMPK) level in skeletal muscle after exposure to acute hypobaric hypoxia and exhaustive exercise. Thirty-two male Sprague-Dawley (SD) rats were randomly divided into sea level and high altitude groups. The rats in high altitude group were submitted to simulated 5 000 m of high altitude in a hypobaric chamber for 24 h, and sea level group was maintained at normal conditions. All the rats were subjected to exhaustive swimming exercise. The exhaustion time was recorded. Before and after the exercise, blood lactate and glycogen content in skeletal muscle were determined; AMPK and pAMPK levels in skeletal muscle were detected by Western blot. The results showed that the exhaustion time was significantly decreased after exposure to high altitude. At the moment of exhaustion, high altitude group had lower blood lactate concentration and higher surplus glycogen content in gastrocnemius compared with sea level group. Exhaustive exercise significantly increased the pAMPK/AMPK ratio in rat skeletal muscles from both sea level and high altitude groups. However, high altitude group showed lower pAMPK/AMPK ratio after exhaustion compared to sea level group. These results suggest that, after exposure to acute hypobaric hypoxia, the decrement in exercise capacity may not be due to running out of glycogen, accumulation of lactate or disturbance in energy status in skeletal muscle.
AMP-Activated Protein Kinases ; metabolism ; Altitude ; Animals ; Computer Simulation ; Glycogen ; metabolism ; Hypoxia ; physiopathology ; Lactic Acid ; blood ; Male ; Motor Activity ; physiology ; Muscle, Skeletal ; enzymology ; metabolism ; Phosphorylation ; Physical Exertion ; physiology ; Rats ; Rats, Sprague-Dawley

The present study was to investigate the effects of diltiazem, a ghrelin receptor agonist, on food intake and gastrointestinal functions in rats. Rats were intragastrically administered with diltiazem solution (daily 16 mg/kg, 30 mg/kg or 80 mg/kg, 30 d), and the rats with saline as control. To detect the effects of diltiazem on food intake and body weight, the average daily food intake and body weight were recorded, and the serum metabolic hormones of plasma growth hormone (GH) and neuropeptide Y (NPY) were tested by radioimmunoassay. By means of the spectrophotometer and the modified Mett's method, the effects of diltiazem on rat's gastrointestinal function and pepsin activity were tested, respectively. In addition, the gastric juice's acidity of rats was detected by titration and the secretion amount was calculated. The results showed that the food intake and body weight were maximally promoted by diltiazem at the dose of 30 mg/kg daily (30 d). The average daily food intake and body weight were significantly increased, and the serum concentrations of GH and NPY were also remarkably increased in diltiazem-treated groups compared with those in control group. The results also showed that the gastric emptying rate, gastric acid secretion and the activity of pepsin were significantly increased in diltiazem-treated group compared with those in control group. These results suggest that diltiazem induces enhancement of eating, in the same time, it can also stimulate the gastrointestinal function and regulate growth of rat.
Animals ; Body Weight ; drug effects ; Diltiazem ; pharmacology ; Eating ; drug effects ; Female ; Gastric Emptying ; drug effects ; Gastrointestinal Motility ; drug effects ; Gastrointestinal Tract ; physiology ; Growth Hormone ; blood ; Neuropeptide Y ; blood ; Rats ; Rats, Sprague-Dawley ; Receptors, Ghrelin ; agonists

To explore the adaptive mechanisms of plateau zokor (Myospalax baileyi) to the enduring digging activity in the hypoxic environment and of plateau pika (Ochotona curzoniae) to the sprint running activity, the functional differences of malate-aspartate shuttle system (MA) in liver of plateau zokor and plateau pika were studied. The ratio of liver weight to body weight, the parameters of mitochondria in hepatocyte and the contents of lactic acid in serum were measured; the open reading frame of cytoplasmic malate dehydrogenase (MDH1), mitochondrial malate dehydrogenase (MDH2), and the partial sequence of aspartate glutamate carrier (AGC) and oxoglutarate malate carrier (OMC) genes were cloned and sequenced; MDH1, MDH2, AGC and OMC mRNA levels were determined by real-time PCR; the specific activities of MDH1 and MDH2 in liver of plateau zokor and plateau pika were measured using enzymatic methods. The results showed that, (1) the ratio of liver weight to body weight, the number and the specific surface of mitochondria in hepatocyte of plateau zokor were markedly higher than those of plateau pika (P < 0.01 or P < 0.05), but the content of lactic acid in serum of plateau pika was significantly higher than that of plateau zokor (P < 0.01); (2) MDH1 and MDH2 mRNA levels as well as their enzymatic activities in liver of plateau zokor were significantly higher than those of plateau pika (P < 0.01 or 0.05), AGC mRNA level of the zokor was significantly higher than that of the pika (P < 0.01), while no difference was found at OMC mRNA level between them (P > 0.05); (3) mRNA level and enzymatic activity of MDH1 was significantly lower than those of MDH2 in the pika liver (P < 0.01), MDH1 mRNA level of plateau zokor was markedly higher than that of MDH2 (P < 0.01), but the activities had no difference between MDH1 and MDH2 in liver of the zokor (P > 0.05). These results indicate that the plateau zokor obtains ATP in the enduring digging activity by enhancing the function of MA, while plateau pika gets glycogen for their sprint running activity by increasing the process of gluconeogenesis. As a result, plateau pika converts the lactic acid quickly produced in their skeletal muscle by anaerobic glycolysis and reduces dependence on the oxygen.
Adaptation, Physiological ; physiology ; Adenosine Triphosphate ; metabolism ; Altitude ; Animals ; Aspartic Acid ; metabolism ; Cloning, Molecular ; L-Lactate Dehydrogenase ; analysis ; metabolism ; Lactic Acid ; blood ; Lagomorpha ; classification ; physiology ; Liver ; anatomy & histology ; physiology ; Malate Dehydrogenase ; genetics ; metabolism ; Malates ; metabolism ; Membrane Transport Proteins ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism

Repeated exposure to morphine leads to the addiction, which influences its clinical application seriously. The glutamatergic projection from prefrontal cortex (PFC) to the nucleus accumbens (NAc) plays an important role in rewarding effects. It is still unknown whether morphine exposure changes PFC-NAc synaptic transmission. To address this question, in vivo field excitatory postsynaptic potentials (fEPSPs) induced by electric stimulating PFC-NAc projection fibers were recorded to evaluate the effect of acute morphine exposure (10 mg/kg, s.c.) on glutamatergic synaptic transmission in NAc shell of repeated saline/morphine pretreated rats. It was showed that acute morphine exposure enhanced fEPSP amplitude and reduced paired-pulse ratio (PPR) in saline pretreated rats, which could be reversed by following naloxone injection (1 mg/kg, i.p.), an opiate receptor antagonist. However, repeated morphine pretreatment significantly inhibited both the enhancement of fEPSP amplitude and reduction of PPR induced by acute morphine exposure. Those results indicate that the initial morphine exposure enhances PFC-NAc synaptic transmission by pre-synaptic mechanisms, whereas morphine pretreatment occludes this effect.
Animals ; Excitatory Postsynaptic Potentials ; drug effects ; physiology ; Female ; Glutamate Plasma Membrane Transport Proteins ; metabolism ; Glutamates ; metabolism ; Morphine ; administration & dosage ; Morphine Dependence ; physiopathology ; Nucleus Accumbens ; physiopathology ; Prefrontal Cortex ; physiopathology ; Rats ; Rats, Sprague-Dawley