While inflammatory bowel disease (IBD) might be a risk factor in the development of brain dysfunctions, the underlying mechanisms are largely unknown. Here, mice were treated with 5% dextran sodium sulfate (DSS) in drinking water and sacrificed on day 7. The serum level of IL-6 increased, accompanied by elevation of the IL-6 and TNF-α levels in cortical tissue. However, the endotoxin concentration in plasma and brain of mice with DSS-induced colitis showed a rising trend, but with no significant difference. We also found significant activation of microglial cells and reduction in occludin and claudin-5 expression in the brain tissue after DSS-induced colitis. These results suggested that DSS-induced colitis increases systemic inflammation which then results in cortical inflammation via up-regulation of serum cytokines. Here, we provide new information on the impact of colitis on the outcomes of cortical inflammation.
Animals ; Calcium-Binding Proteins ; metabolism ; Caspase 3 ; metabolism ; Cerebral Cortex ; pathology ; Claudin-5 ; metabolism ; Colitis ; chemically induced ; complications ; pathology ; Cytokines ; genetics ; metabolism ; Dextran Sulfate ; toxicity ; Disease Models, Animal ; Encephalitis ; etiology ; Gene Expression Regulation ; drug effects ; Mice ; Microfilament Proteins ; metabolism ; Occludin ; metabolism ; Polysaccharides ; blood ; toxicity ; Time Factors

OBJECTIVETo investigate acrylamide (ACR)-induced subacute neurotoxic effects on the central nervous system (CNS) at the synapse level in rats.

METHODSThirty-six Sprague Dawley (SD) rats were randomized into three groups, (1) a 30 mg/kg ACR-treated group, (2) a 50 mg/kg ACR-treated group, and (3) a normal saline (NS)-treated control group. Body weight and neurological changes were recorded each day. At the end of the test, cerebral cortex and cerebellum tissues were harvested and viewed using light and electron microscopy. Additionally, the expression of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were investigated.

RESULTSThe 50 mg/kg ACR-treated rats showed a significant reduction in body weight compared with untreated individuals (P < 0.05). Rats exposed to ACR showed a significant increase in gait scores compared with the NS control group (P < 0.05). Histological examination indicated neuronal structural damage in the 50 mg/kg ACR treatment group. The active zone distance (AZD) and the nearest neighbor distance (NND) of synaptic vesicles in the cerebral cortex and cerebellum were increased in both the 30 mg/kg and 50 mg/kg ACR treatment groups. The ratio of the distribution of synaptic vesicles in the readily releasable pool (RRP) was decreased. Furthermore, the expression levels of Synapsin I and P-Synapsin I in the cerebral cortex and cerebellum were decreased in both the 30 mg/kg and 50 mg/kg ACR treatment groups.

CONCLUSIONSubacute ACR exposure contributes to neuropathy in the rat CNS. Functional damage of synaptic proteins and vesicles may be a mechanism of ACR neurotoxicity.

Acrylamide ; toxicity ; Animals ; Cerebellum ; cytology ; drug effects ; Cerebral Cortex ; cytology ; drug effects ; Drug Administration Schedule ; Gait ; Gene Expression Regulation ; drug effects ; Male ; Neurons ; drug effects ; Neurotoxicity Syndromes ; pathology ; Rats ; Rats, Sprague-Dawley ; Synapses ; drug effects ; Synapsins ; genetics ; metabolism ; Synaptic Vesicles ; drug effects ; physiology ; Weight Loss ; drug effects

OBJECTIVETo investigate the effect of corticosterone on the expression of the neuronal migration protein lissencephaly 1 (LIS1) in developing cerebral cortical neurons of fetal rats.

METHODSThe primary cultured cerebral cortical neurons of fetal Wistar rats were divided into control group, low-dose group, and high-dose group. The neurons were exposed to the medium containing different concentrations of corticosterone (0 μmol/L for the control group, 0.1 μmol/L for the low-dose group, and 1.0 μmol/L for the high-dose group). The neurons were collected at 1, 4, and 7 days after intervention. Western blot and immunocytochemical staining were used to observe the change in LIS1 expression in neurons.

RESULTSWestern blot showed that at 7 days after intervention, the low- and high-dose groups had significantly higher expression of LIS1 in the cytoplasm and nucleus of cerebral cortical neurons than the control group (P<0.05), and the high-dose group had significantly lower expression of LIS1 in the cytoplasm of cerebral cortical neurons than the low-dose group (P<0.05). Immunocytochemical staining showed that at 1, 4, and 7 days after corticosterone intervention, the high-dose group had a significantly lower mean optical density of LIS1 than the control group and the low-dose group (P<0.05). At 7 days after intervention, the low-dose group had a significantly lower mean optical density of LIS1 than the control group (P<0.05).

CONCLUSIONSCorticosterone downregulates the expression of the neuronal migration protein LIS1 in developing cerebral cortical neurons of fetal rats cultured in vitro, and such effect depends on the concentration of corticosterone and duration of corticosterone intervention.

1-Alkyl-2-acetylglycerophosphocholine Esterase ; analysis ; genetics ; Animals ; Cells, Cultured ; Cerebral Cortex ; drug effects ; metabolism ; Corticosterone ; pharmacology ; Dose-Response Relationship, Drug ; Female ; Fetus ; drug effects ; Microtubule-Associated Proteins ; analysis ; genetics ; Pregnancy ; Rats ; Rats, Wistar

OBJECTIVETo investigate the protective effect of histone acetylation against hypoxic-ischemic cortical injury in neonatal rats.

METHODSA total of 90 neonatal rats aged 3 days were divided into three groups: sham-operation, cortical injury model, and sodium butyrate (a histone deacetylase inhibitor) treatment. The rats in the model and the sodium butyrate treatment groups were intraperitoneally injected with lipopolysaccharide (0.05 mg/kg), and then right common carotid artery ligation was performed 2 hours later and the rats were put in a hypoxic chamber (oxygen concentration 6.5%) for 90 minutes. The rats in the sham-operation group were intraperitoneally injected with normal saline and the right common carotid artery was only separated and exposed without ligation or hypoxic treatment. The rats in the sodium butyrate treatment group were intraperitoneally injected with sodium butyrate (300 mg/kg) immediately after establishment of the cortical injury model once a day for 7 days. Those in the sham-operation and the model groups were injected with the same volume of normal saline. At 7 days after establishment of the model, Western blot was used to measure the protein expression of histone H3 (HH3), acetylated histone H3 (AH3), B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (BAX), cleaved caspase-3 (CC3), and brain-derived neurotrophic factor (BDNF). Immunofluorescence assay was used to measure the expression of 5-bromo-2'-deoxyuridine (BrdU) as the cortex cell proliferation index.

RESULTSThe sodium butyrate treatment group had a significantly lower HH3/AH3 ratio than the model group (P<0.05), which suggested that the sodium butyrate treatment group had increased acetylation of HH3. Compared with the model group, the sodium butyrate treatment group had a significant increase in Bcl-2/Bax ratio, a significant reduction in CC3 expression, and a significant increase in BDNF expression (P<0.05). The sodium butyrate treatment group had a significant increase in the number of BrdU-positive cells in the cortex compared with the model group (P<0.05), and BrdU was mainly expressed in the neurons.

CONCLUSIONSIncreased histone acetylation may protect neonatal rats against cortical injury by reducing apoptosis and promoting regeneration of neurons. The mechanism may be associated with increased expression of BDNF.

Acetylation ; Animals ; Animals, Newborn ; Apoptosis ; drug effects ; Brain-Derived Neurotrophic Factor ; analysis ; Butyric Acid ; therapeutic use ; Cerebral Cortex ; pathology ; Female ; Histones ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the changes of telemetry electrical activity in the infralimbic cortex (IL) of morphine-dependent rats with extinguished drug-seeking behavior.

METHODSSD rats were randomly divided into model group and control group and received operations of brain stereotaxic electrode embedding in the IL. The rats in the model group were induced to acquire morphine dependence and then received subsequent extinction training, and the changes of electrical activity in the IL were recorded with a physical wireless telemetry system.

RESULTSIn rats with morphine dependence, the time staying in the white box was significantly longer on days 1 and 2 after withdrawal than that before morphine injection and that of the control rats, but was obviously reduced on days 1 and 2 after extinction training to the control level. Compared with the control group, the morphine-dependent rats on day 2 following withdrawal showed significantly increased β wave and decreased δ wave when they stayed in the white box but significantly increased δ wave and decreased α wave and β wave when they shuttled from the black to the white box. On day 2 of extinction, the model rats, when staying in the white box, showed significantly decreased θ wave compared with that of the control rats group but decreased β wave and θ wave and increased δ wave compared with those in the withdrawal period. When they shuttled from black to white box, the model rats showed decreased δ wave and increased α wave and β wave compared with those in the withdrawal period.

CONCLUSIONMorphine-dependent rats have abnormal changes of electrical activity in the IL in drug-seeking extinction to affect their drug-seeking motive and inhibit the expression and maintenance of drug-seeking behaviors.

Animals ; Cerebral Cortex ; drug effects ; physiology ; Drug-Seeking Behavior ; physiology ; Electrophysiological Phenomena ; Extinction, Psychological ; Morphine ; pharmacology ; Morphine Dependence ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Telemetry

OBJECTIVETo explore the role of P53 phosphorylation in neuron apoptosis of rats by chronic aluminum exposure.

METHODSA total of male 40 SD rats were divided randomly into 4 groups (n = 10/dose), the exposed groups were fed with normal diet with different concentration of AlCl3 · 6H2O for 6 months respectively. The dosage of low, middle and high groups were 10.73, 107.33, 1073.33 mg/kg in sequence. The control group received normal diet. The neuron apoptosis was measured by method of Tunel. The expressions of P53 and pP53-ser15 protein in the cortex were detected by Western-blot.

RESULTSTunel staining showed that the low, middle and high group rats had increased apoptosis rate than control group (P < 0.01). Western-blot test demonstrated that the expression of P53 protein in the cortex of high group rats were significantly higher than the control and low groups (P < 0.05). The expression of pP53-ser15 protein in the cortex of middle and high group rats were also higher than the control and low groups (P < 0.05).

CONCLUSIONChronic aluminum exposure can lead to over expression of P53 and pP53-ser15 protein in cerebral cortex, which maybe one of the most important mechanisms of neuron apoptosis induced by AlCl3.

Aluminum ; toxicity ; Aluminum Compounds ; toxicity ; Animals ; Apoptosis ; Cerebral Cortex ; metabolism ; Chlorides ; toxicity ; Male ; Neurons ; cytology ; drug effects ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo study the toxicity of methomyl to acetylcholinesterase (AChE) in different regions.

METHODSThe optimal temperature and time for measurement of AChE activity were determined in vitro. The dose- and time-response relationships of methomyl with AChE activity in human erythrocyte membrane, rat erythrocyte membrane, cortical synapses, cerebellar synapses, hippocampal synapses, and striatal synapses were evaluated. The half maximal inhibitory concentration (IC50) and bimolecular rate constant (K) of methomyl for AChE activity in different regions were calculated, and the type of inhibition of AChE activity by methomyl was determined.

RESULTSAChE achieved the maximum activity at 370 °C, and the optimal time to determine initial reaction velocity was 0-17 min. There were dose- and time-response relationships between methomyl and AChE activity in the erythrocyte membrane and various brain areas. The IC50 value of methomyl for AChE activity in human erythrocyte membrane was higher than that in rat erythrocyte membrane, while the Ki value of methomyl for AChE activity in rat erythrocyte membrane was higher than that in human erythrocyte membrane. Among synapses in various brain areas, the striatum had the highest IC50 value, followed by the cerebellum, cerebral cortex, and hippocampus, while the cerebral cortex had the highest Ki value, followed by the hippocampus, striatum, and cerebellum. Lineweaver-Burk diagram demonstrated that with increasing concentration of methomyl, the maximum reaction velocity (Vmax) of AChE decreased, and the Michaelis constant (Km) remained the same.

CONCLUSIONMethomyl is a reversible non-competitive inhibitor of AChE. AChE of rat erythrocyte membrane is more sensitive to methomyl than that of human erythrocyte membrane; the cerebral cortical synapses have the most sensitive AChE to methomyl among synapses in various brain areas.

Acetylcholinesterase ; metabolism ; Animals ; Cerebellum ; drug effects ; Cerebral Cortex ; drug effects ; Erythrocyte Membrane ; drug effects ; enzymology ; Hippocampus ; drug effects ; Humans ; Inhibitory Concentration 50 ; Methomyl ; toxicity ; Rats ; Synapses ; drug effects ; Toxicity Tests

OBJECTIVETo investigate the effects of nano-lead exposure on learning and memory and iron homeostasis in the brain of the offspring rats on postnatal day 21 (PND21) and postnatal day 42 (PND42).

METHODSTwenty adult pregnant female Sprague-Dawley rats were randomly divided into control group and nano-lead group. Rats in the nano-lead group were orally administrated 10 mg/kg nano-lead, while rats in the control group were administrated an equal volume of normal saline until PND21. On PND21, the offspring rats were weaned and given the same treatment as the pregnant rats until 42 days after birth. The learning and memory ability of offspring rats on PND21 and PND42 was evaluated by Morris water maze test. The hippocampus and cortex s amples of offspring rats on PND21 and PND42 were collected to determine iron and lead levels in the hippocampus and cortex by inductively coupled plasma-mass spectrometry. The distributions of iron in the hippocampus and cortex were observed by Perl's iron staining. The expression levels of ferritin, ferroportin 1 (FPN1), hephaestin (HP), and ceruloplasmin (CP) were measured by enzyme-linked immunosorbent assay.

RESULTSAfter nano-lead exposure, the iron content in the cortex of offspring rats on PND21 and PND42 in the nano-lead group was significantly higher than those in the control group (32.63 ± 6.03 µg/g vs 27.04 ± 5.82 µg/g, P<0.05; 46.20 ±10.60 µg/g vs 36.61 ± 10.2µg/g, P<0.05). The iron content in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly higher than that in the control group (56.9 ± 4.37µg/g vs 37.71 ± 6.92µg/g, P<0.05). The Perl's staining showed massive iron deposition in the cortex and hippocampus in the nano-lead group. FPNl level in the cotfex of offspring rats on PND21 in the nano-lead group was significantly lower than that in the control group (3.64 ± 0.23 ng/g vs 4.99 ± 0.95 ng/g, P<0.05). FPN1 level in the hippocampus of offspring rats on PND42 in the nano-lead group was significantly lower than that in the control group (2.28 ± 0.51 ng/g vs 3.69 ± 0.69 ng/g, P<0.05). The escape latencies of offspring rats on PND21 and PND42 in the nano-lead group were longer than those in the control group (15.54 ± 2.89 s vs 9.01 ± 4.66 s; 6.16 ± 1.42 s vs 4.26 ± 1.51 s). The numbers of platform crossings of offspring rats on PND21 and PND42 in the nano- lead group were significantly lower than those in the control group (7.77 ± 2.16 times vs 11.2 ± 1.61 times, P<0.05; 8.12 ± 1.51 times vs 13.0 ± 2.21 times, P<0.05).

ONCLUSIONn Nano-lead exposure can result in iron homeostasis disorders in the hippocampus and cortex of offspring rats and affect their learning and memory ability.

Animals ; Cerebral Cortex ; drug effects ; metabolism ; Female ; Hippocampus ; drug effects ; metabolism ; Homeostasis ; Iron ; metabolism ; Lead ; toxicity ; Learning ; drug effects ; Maternal Exposure ; adverse effects ; Memory ; drug effects ; Pregnancy ; Rats ; Rats, Sprague-Dawley

To assess the neurotoxic effects and redox responses of Aroclor 1254 (A1254) on perinatally exposed rat offspring, A1254 was administered by gavage from gestational day (GD) 6 to postnatal day (PND) 21. Neurobehavioral development, antioxidant enzyme activities, lipid peroxidation (LPO), nitric oxide (NO), and NO synthase (NOS) levels were analyzed in the offspring. Neurobehavioral development analysis revealed delayed appearance of the righting reflex, negative geotaxis, and cliff drop test responses in A1254 exposed group. Developmental A1254 exposure also caused oxidative stress in the brain of PND 22 offspring via reductions in the activity of SOD and GSH-Px, and by promoting a rise in the levels of NO and NOS.
Aging ; metabolism ; Animals ; Cerebral Cortex ; drug effects ; enzymology ; metabolism ; Chlorodiphenyl (54% Chlorine) ; toxicity ; Female ; Glutathione Peroxidase ; metabolism ; Kidney ; drug effects ; enzymology ; metabolism ; Lipid Peroxidation ; drug effects ; Liver ; drug effects ; enzymology ; metabolism ; Mice ; Nervous System ; drug effects ; growth & development ; metabolism ; physiopathology ; Nervous System Diseases ; chemically induced ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Oxidative Stress ; drug effects ; Pregnancy ; Prenatal Exposure Delayed Effects ; chemically induced ; Random Allocation ; Rats ; Superoxide Dismutase ; metabolism

OBJECTIVETo investigate the potential involvement of DMT1 (IRE) protein in the brain vascular system in vivo during Pb exposure.

METHODSThree groups of male Sprague-Dawley rats were exposed to Pb in drinking water, among which two groups were concurrently administered by oral gavage once every other day as the low and high Fe treatment group, respectively, for 6 weeks. At the same time, the group only supplied with high Fe was also set as a reference. The animals were decapitated, then brain capillary-rich fraction was isolate from cerebral cortex. Western blot method was used to identify protein expression, and RT-PCR to detect the change of the mRNA.

RESULTSPb exposure significantly increased Pb concentrations in cerebral cortex. Low Fe dose significantly reduced the cortex Pb levels, However, high Fe dose increased the cortex Pb levels. Interestingly, changes of DMT1 (IRE) protein in brain capillary-rich fraction were highly related to the Pb level, but those of DMT1 (IRE) mRNA were not significantly different. Moreover, the consistent changes in the levels of p-ERK1/2 or IRP1 with the changes in the levels of DMT1 (IRE).

CONCLUSIONThese results suggest that Pb is transported into the brain through DMT1 (IRE), and the ERK MAPK pathway is involved in DMT1 (IRE)-mediated transport regulation in brain vascular system in vivo.

Animals ; Blood-Brain Barrier ; drug effects ; metabolism ; Cation Transport Proteins ; drug effects ; genetics ; physiology ; Cerebral Cortex ; drug effects ; metabolism ; Dietary Supplements ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Gene Expression Regulation ; drug effects ; Iron ; administration & dosage ; metabolism ; Lead ; administration & dosage ; pharmacokinetics ; MAP Kinase Signaling System ; physiology ; Male ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley