Dynamic expression of nerve growth factor and its receptor Trk A after subarachnoid hemorrhage in rat brain

Delayed ischemic neurologic deficit after subarachnoid hemorrhage results from loss of neural cells.Nerve growth factor and its receptor Trk A may promote regeneration of neural cells,but their expression after subarachnoid hemorrhage remains unclear.In the present study,a rat model of subarachnoid hemorrhage was established using two injections of autologous blood into the cistern magna.Immunohistochemical staining suggested that the expression of nerve growth factor and Trk A in the cerebral cortex and brainstem increased at 6 hours,peaked at 12 hours and decreased 1 day after induction of subarachnoid hemorrhage,whereas the expression in the hippocampus increased at 6 hours,peaked on day 1,and decreased 3 days later.Compared with those for the rats in the sham and saline groups,neurobehavioral scores decreased significantly 12 hours and 3 days after subarachnoid hemorrhage（P 〈 0.05）.These results suggest that the expression of nerve growth factor and its receptor Trk A is dynamically changed in the rat brain and may thus participate in neuronal survival and nerve regeneration after subarachnoid hemorrhage.

Dynamic Expression of Hyperpolarization-activated Cyclic Nucleotide-gated Cation Channel 4 Involved in Microwave Induced Pacemaker Cell Injuries

To investigate the mechanisms of microwave induced pacemaker cell injuries, Wistar rats and the primary pacemaker cells of newborn Wistar rats were exposed to microwave at average power density of 50 mW/cm2. Slower spontaneous beating rate, intercellular Ca2＋ aggregation and cell membrane perforation were detected immediately after the exposure. Moreover, hyperpolarizationactivated cyclic nucleotide-gated cation channel 4 （HCN4） was down-regulated immediately after the exposure and up-regulated at 12 h after the exposure. In the sinoatrial node （SAN） of the rats,

Functional near-infrared spectroscopy can detect low-frequency hemodynamic oscillations in the prefrontal cortex during steady-state visual evoked potentialinducing periodic facial expression stimuli presentation

Brain oscillations are vital to cognitive functions,while disrupted oscillatory activity is linked to various brain disorders.Although high-frequency neural oscillations(>1 Hz)have been extensively studied in cognition,the neural mechanisms underlying low-frequency hemodynamic oscillations(LFHO)<1 Hz have not yet been fully explored.One way to examine oscillatory neural dynamics is to use a facial expression(FE)paradigm to induce steady-state visual evoked potentials(SSVEPs),which has been used in electroencephalography studies of high-frequency brain oscillation activity.In this study,LFHO during SSVEP-inducing periodic flickering stimuli presentation were inspected using functional near-infrared spectroscopy(fNIRS),in which hemodynamic responses in the prefrontal cortex were recorded while participants were passively viewing dynamic FEs flickering at 0.2 Hz.The fast Fourier analysis results demonstrated that the power exhibited monochronic peaks at 0.2 Hz across all channels,indicating that the periodic events successfully elicited LFHO in the prefrontal cortex.More importantly,measurement of LFHO can effectively distinguish the brain activation difference between different cognitive conditions,with happy FE presentation showing greater LFHO power than neutral FE presentation.These results demonstrate that stimuli flashing at a given frequency can induce LFHO in the prefrontal cortex,which provides new insights into the cognitive mechanisms involved in slow oscillation.

Oncogenic Wnt3a is a promising sensitive biomarker for monitoring hepatocarcinogenesis

Background:The effective treatment for hepatocellular carcinoma(HCC)depends on early diagnosis.Previously,the abnormal expression of Wnt3a as the key signaling molecule in the Wnt/β-catenin pathway was found in HCC cells and could be released into the circulation.In this study,we used rat model of hepatocarcinogenesis to dynamically investigate the alteration of oncogenic Wnt3a and to explore its early monitor value for HCC.Methods:Sprague-Dawley rats(SD)were fed with diet 2-fluorenylacetamide(2-FAA,0.05%)for inducing hepatocarcinogenesis,and grouped based on liver morphological alteration by Hematoxylin&Eosin(H&E)staining;rats fed with normal chow were used as normal control(NC).Total RNA and protein were purified from rat livers.Differently expressed genes(DEGs)or Wnt3a m RNA,cellular distribution,and Wnt3a protein levels were analyzed by whole genome microarray with signal logarithm ratio(SLR log 2 cy5/cy3),immunohistochemistry,and enzyme-linked immunosorbent assay,respectively.Results:Models of rat hepatocarcinogenesis were successfully established based on liver histopathological H&E staining.Rats were divided into the cell degeneration(r Deg),precancerosis(r Pre-C)and HCC(r HCC)groups.Total numbers of the up-and down-regulated DEGs with SLR≥8 were 55 and 48 in the r Deg group,268 and 57 in the r Pre-C group,and 312 and 201 in the r HCC group,respectively.Significantly altered genes were involved in cell proliferation,signal transduction,tumor metastasis,and apoptosis.Compared with the NC group,Wnt3a m RNA was increased by 4.6 folds(P<0.001)in the r Deg group,7.4 folds(P<0.001)in the r Pre-C group,and 10.4 folds(P<0.001)in the r HCC group;the positive rates of liver Wnt3a were 66.7%(P=0.001)in the r Deg group,100%(P<0.001)in the r Pre-C group,and 100%(P<0.001)in the r HCC group,respectively.Also,there were significant differences of liver Wnt3a(P<0.001)or serum Wnt3a(P<0.001)among different groups.Conclusions:Overexpression of Wnt3a was associated with rat hepatocarcinogenesis and it should be expected to be a promising monitoring biomarker for HCC occurrence at early stage.

iHypoxia:An Integrative Database of Protein Expression Dynamics in Response to Hypoxia in Animals

Mammals have evolved mechanisms to sense hypoxia and induce hypoxic responses.Recently,high-throughput techniques have greatly promoted global studies of protein expression changes during hypoxia and the identification of candidate genes associated with hypoxiaadaptive evolution,which have contributed to the understanding of the complex regulatory networks of hypoxia.In this study,we developed an integrated resource for the expression dynamics of proteins in response to hypoxia(iHypoxia),and this database contains 2589 expression events of 1944 proteins identified by low-throughput experiments(LTEs)and 422,553 quantitative expression events of 33,559 proteins identified by high-throughput experiments from five mammals that exhibit a response to hypoxia.Various experimental details,such as the hypoxic experimental conditions,expression patterns,and sample types,were carefully collected and integrated.Furthermore,8788 candidate genes from diverse species inhabiting low-oxygen environments were also integrated.In addition,we conducted an orthologous search and computationally identified 394,141 proteins that may respond to hypoxia among 48 animals.An enrichment analysis of human proteins identified from LTEs shows that these proteins are enriched in certain drug targets and cancer genes.Annotation of known posttranslational modification(PTM)sites in the proteins identified by LTEs reveals that these proteins undergo extensive PTMs,particularly phosphorylation,ubiquitination,and acetylation.iHypoxia provides a convenient and user-friendly method for users to obtain hypoxia-related information of interest.

Delayed hepatocarcinogenesis through antiangiogenic intervention in the nuclear factor-kappa B activation pathway in rats

BACKGROUND: The active form of nuclear factor-kappa B (NF-kappa B) is involved in the initiation, generation, and development of hepatocellular carcinoma (HCC), and is up-regulated in inflammation-associated malignancies. We investigated the dynamic expression of NF-kappa B and its influences on the occurrence of HCC through antiangiogenic (thalidomide) intervention in NF-kappa B activation. METHODS : Hepatoma models were induced with 2-fluorenylacetamide (2-FAA, 0.05%) in male Sprague-Dawley rats, and thalidomide (100 mg/kg body weight) was administered intragastrically to intervene in NF-kappa B activation. The pathological changes in the liver of sacrificed rats were assessed after hematoxylin and eosin staining. NF-kappa B mRNA was amplified by RT-nested PCR. The alterations of NF-kappa B and vascular endothelial growth factor (VEGF) expression were analyzed by enzyme-linked immunosorbent assay, immunohistochemistry, and Western blotting. RESULTS: Rat hepatocytes showed denatured, precancerous, and cancerous stages in hepatocarcinogenesis, with an increasing tendency of hepatic NF-kappa B, NF-kappa B mRNA, and VEGF expression, and their values in the HCC group were higher than those in controls (P<0.001). In the thalidomide-treated group, the morphologic changes generated only punctiform denaturation and necrosis at the early or middle stages, and nodular hyperplasia or a little atypical hyperplasia at the final stages, with the expression of NF-kappa B (chi(2)=9.93, P<0.001) and VEGF (chi(2)=8.024, P<0.001) lower than that in the 2-FAA group. CONCLUSION: NF-kappa B is overexpressed in hepatocarcinogenesis and antiangiogenic treatment down-regulates the expression of NF-kappa B and VEGF, and delays the occurrence of HCC. (Hepatobiliary Pancreat Dis Int 2010; 9: 169-174)

Mitochondrial carnitine palmitoyl transferase-Ⅱ inactivity aggravates lipid accumulation in rat hepatocarcinogenesis

AIM To investigate the dynamic alteration of mitochondrial carnitine palmitoyl transferase Ⅱ(CPT-Ⅱ) expression during malignant transformation of rat hepatocytes.METHODS Sprague-Dawley male rats were fed with normal, high fat(HF), and HF containing 2-fluorenylacetamide(2-FAA) diet, respectively. According to the Hematoxylin and Eosin staining of livers, rats were divided into control, fatty liver, degeneration, pre-cancerous, and cancerous groups. Liver lipids were dyed with Oil Red O, CPT-Ⅱ alterations were analyzed by immunohistochemistry, and compared with CPT-Ⅱ specific concentration(μg/mg protein). Levels of total cholesterol(Tch), triglyceride(TG), and aminotransferases [alanine aminotransferase(ALT), aspartate aminotransferase(AST)] were determined by the routine methods.RESULTS After intake of HF and/or HF+2-FAA diets, the rat livers showed mass lipid accumulation. The lipid level in the control group was significantly lower than that in other groups. The changes of serum TG and Tch levels were abnormally increasing, 2-3 times more than those in the controls(P < 0.05). During the rat liver morphological changes from normal to cancer development process with hepatocyte injury, serum AST and ALT levels were significantly higher(4-8 times, P < 0.05) than those in the control group. The specific concentration of CPT-Ⅱ in liver tissues progressively decreased during hepatocyte malignant transformation, with the lowest CPT-Ⅱ levels in the cancer group than in any of the other groups(P < 0.05).CONCLUSION Low CPT-Ⅱ expression might lead to abnormal hepatic lipid accumulation, which should promote the malignant transformation of hepatocytes.

Abnormal CD44 activation of hepatocytes with nonalcoholic fatty accumulation in rat hepatocarcinogenesis

BACKGROUND Prevalence of nonalcoholic fatty liver disease(NAFLD)is rapidly increasing,and NAFLD has become one of the most common chronic liver diseases worldwide.With abnormal CD44 activation,the severe form of NAFLD can progress to liver cirrhosis and hepatocellular carcinoma(HCC).Thus,the molecular mechanism of CD44 in NAFLD needs to be identified.AIM To investigate the relationship between CD44 activation and malignant transformation of rat hepatocytes under nonalcoholic lipid accumulation.METHODS Sprague-Dawley rats were fed a high-fat(HF)for 12 wk to entice NAFLD and then with HF plus 2-fluorenylacetamide(0.05%)to induce HCC.Rats were sacrificed every 2 wk,and subsequently divided into the groups based on liver pathological examination(hematoxylin and eosin staining):NAFLD,denaturation,precancerosis,HCC,and control.Liver CD44 mRNA was detected by OneArray.Liver fat as assessed by Oil red O staining or CD44 by immunohistochemical assay was compared with their integral optic density.Serum CD44,alanine aminotransferase,aspartate aminotransferase,triglyceride,total cholesterol,and AFP levels were quantitatively tested.RESULTS Elevated CD44 was first reported in hepatocarcinogenesis,with increasing expression from NAFLD to HCC at the protein or mRNA level.The CD44 integral optic density values were significantly different between the control group and the NAFLD(t=25.433,P<0.001),denaturation(t=48.822,P<0.001),precancerosis(t=27.751,P<0.001),and HCC(t=16.239,P<0.001)groups,respectively.Hepatic CD44 can be secreted into the blood,and serum CD44 levels in HCC or precancerous rats were significantly higher(P<0.001)than those in any of the other rats.Positive correlations were found between liver CD44 and CD44 mRNA(rs=0.373,P=0.043)and serum CD44(rs=0.541,P=0.002)and between liver CD44 mRNA and serum CD44(rs=0.507,P=0.004).Moreover,significant correlations were found between liver CD44 and liver AFP(rs=0.572,P=0.001),between serum CD44 and serum AFP(rs=0.608,P<0.001),and between CD44 mRNA and AFP mRNA(rs=0.370,P=0.044).CONCLUSION The data suggested that increasing CD44 expression is associated with the malignant transformation of hepatocytes in NAFLD.

The Expressibility of First Order Dynamic Logic

This paper resolved an open problem proposed by A .P. Stolboushkin and M .A. Taitslin. We studied the expressibility of first order dynamic logic, and constructed infinite recursive program classes K_1 , K_2, …, RG K_1 K_2 … RF, such that L (RG)<L (K_1)<L (K_2) < … < L (RF), where RG, RF are regular program class and finitely generated recursively enumerable program class respectively, and L (K) is the first order dynamic logic of program class K.