OBJECTIVETo investigate the effects of formaldehyde inhalation on the morphological damage, and Glu, GABA and NOS contents in olfactory bulb and hippocampus of rats.

METHODSTwenty SD rats were equally divided into two groups: rats in the control group inhaled fresh air, while the animals in experimental group were exposed to the air containing formaldehyde (12.5 mg/m(3), 4 h/d) for 7 days. Then rats were sacrificed and frozen sections of olfactory bulb and hippocampus were prepared. The morphological changes were examined and the Glu, GABA and NOS contents were detected using Nissl-staining, immunohistochemistry and Western blot, respectively.

RESULTCompared with the control group, there was a significant confusion and shrink of neuron morphology in experimental group, the number and staining intensity of Glu and NOS positive cells and protein contents were reduced. The protein expression of GABA was also decreased in the formaldehyde group.

CONCLUSIONFormaldehyde inhalation can cause a severe morphological damage of olfactory bulb and hippocampus in SD rats,which may further impair memory and learning ability through the reduction of Glu, GABA and NOS expression.

Animals ; Formaldehyde ; toxicity ; Glutamic Acid ; metabolism ; Hippocampus ; drug effects ; metabolism ; pathology ; Inhalation Exposure ; Learning ; drug effects ; Neurons ; drug effects ; metabolism ; pathology ; Nitric Oxide Synthase ; metabolism ; Olfactory Bulb ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; metabolism

OBJECTIVETo study the effects of deltamethrin on intracellular free Ca2+ concentration and apoptosis in rat neural cells.

METHODSWister rats were randomly divided into 4 groups(3 treated groups and 1 control). Intracellular free Ca2+ concentration in rat neural cells was measured by using the fluorescent Ca2+ indicator Fura-2/AM. Apopotic rate of neural cells was measured by using FACS420 Flow Cytometer.

RESULTSIntracellular free Ca2+ concentration at 5 h after deltamethrin exposure [hippocampus: (389.94 +/- 43.64) nmol/L, cerebral cortex: (449.33 +/- 23.23) nmol/L], at 24 h[hippocampus: (340.47 +/- 32.36) nmol/L, cerebral cortex: (311.62 +/- 25.48) nmol/L] and at 48 h[hippocampus: (287.13 +/- 24.29) nmol/L, cerebral cortex: (346.55 +/- 36.87) nmol/L] were all higher than those of the control group[hippocampus: (203.24 +/- 18.53) nmol/L, cerebral cortex: (226.85 +/- 14.81) nmol/L, P < 0.01]; Apoptotic rate in neural cells 24 h and 48 h later [hippocampus: (8.45 +/- 1.02)%, (9.44 +/- 1.14)%, cerebral cortex: (7.90 +/- 0.49)%, (8.01 +/- 0.87)%] were also higher than those of the control group[hippocampus: (2.97 +/- 0.36)%, cerebral cortex: (3.50 +/- 0.48)%, P < 0.01)] and increased with time prolonged.

CONCLUSIONExposure to high dose of deltamethrin would interfere with intracellular free Ca2+ concentration and apoptotic rate in rat neural cells, suggesting that there may be certain relation between them.

Animals ; Apoptosis ; drug effects ; Calcium ; metabolism ; Cerebral Cortex ; drug effects ; metabolism ; pathology ; Flow Cytometry ; Hippocampus ; drug effects ; metabolism ; pathology ; Insecticides ; toxicity ; Neurons ; cytology ; drug effects ; metabolism ; Nitriles ; toxicity ; Pyrethrins ; toxicity ; Rats ; Rats, Wistar

To study the relationship between tau hyperphosphorylation and the function of glutamate transporter okadaic acid (OA), a protein phosphatase inhibitor, 20 ng in a 0.5 microl volume, was injected into the frontal cortex of rat brain and immunostaining was used to observe the phosphorylation of tau protein and the expression of excitatory amino acid transporter 1 (EAAT1) in the brain following the injection. The results showed that (1) the neurons in the center of the injection region displayed cytoplasmic shrinkage, swelling, nuclear pyknosis, and dislocation at the early stage, and necrosis appeared 3 d after the injection. However, most neurons in the peri-injected areas showed normal morphological characters with immuno positive reaction for AT8, a tau phosphorylated marker; (2) morphological analysis showed that tau hyperphosphorylation caused by OA treatment was mainly observed in the axons and dendrites of neuronal cells at 6 h in the cell body at 1 d, which brought about dystrophic neurites and neurofibrillary tangle (NFT)-like pathological changes; (3) the induction of glutamate transporter EAAT1 was observed in the involved areas corresponding to that with AT8 immunopositive staining, and the number of EAAT1-positive staining cells markedly increased at 12 h (P<0.01), peaked at 1 d (P<0.001), then decreased at 3 d following the injection. Combined with a confocal laser scanning microscopic analysis, double fluorescent immunostaining showed that EAAT1 positive staining appeared in neurons as well as astrocytes in the peri-injected areas of the frontal cortex. These results demonstrate that OA increases glutamate transporter EAAT1 expression in neurons while it induces tau hyperphosphorylation. However, the mechanism and significance of the induction of glutamate transporter EAAT1 expression remain to be further elucidated.
Animals ; Astrocytes ; drug effects ; metabolism ; Axons ; drug effects ; metabolism ; Brain ; cytology ; Dendrites ; drug effects ; metabolism ; Excitatory Amino Acid Transporter 1 ; metabolism ; Neurofibrillary Tangles ; pathology ; Neurons ; drug effects ; metabolism ; Okadaic Acid ; pharmacology ; Phosphorylation ; Rats ; tau Proteins ; metabolism

OBJECTIVETo investigate the effect of curcumin on the injury in hippocampal neurons and the expression of regulated upon activation nonnal T-cell expressed and secreted (RANTES) in hippocamp during cerebral ischemia/reperfusion (I/R) in rats with spontaneous hypertension (SH).

METHODSMale Wistar-Kyoto (WKY) rats and spontaneous hypertension rats (SHR) were randomly divided into five groups (n = 6): sham group (W-Sham and S-Sham group), ischemia/reperfusion group (W-/R and S/R group), curcumin group (S-Cur group) . Each group was splitted into 5 subgroups of 3 h,12 h, 1 d, 3 d and 7 d according to the time interval before reperfusion. Global brain ischemia/reperfusion model was established by 4-VO method. Hematoxylin-eosin staining (HE staining) was used to observe the vertebral cell morphology in hippocampal CA1 region. Nissl staining was applied to detect the average density of cone cells in hippocampal CA1 region. The expression of RANTES in hippocamp was determined by ELISA. The behavior of the rats was evaluated at 7 days after reperfusion. Results: Compared with the sham group rats, the ability of learning and memory was significantly decreased in ischemia/reperfusion group rats, the number of injured neurons were greatly elevated , the protein expression levels of RANTES was significantly increased (P < 0.05). Compared with W-I/R group rats, the ability of learning and memory in S-I/R group rats was greatly reduced, the number of injured neurons increased extremely, the protein expression level of RANTES was significantly enhanced( P <0.05). The number of injured neurons declined significantly in S-Cur group rats, the ability to learn and remember of these rats was improved and the RANTES protein content decreased significantly (P < 0.05).

CONCLUSIONSHR are more susceptible to ischemia/reperfusion induced hippocampal neuronal injury which may be improved by curcu min. Its underlying mechanism is possibly associated with the inhibition of RANTES protein expression level.

Animals ; Brain Ischemia ; metabolism ; pathology ; physiopathology ; Chemokine CCL5 ; metabolism ; Cognition ; drug effects ; Curcumin ; pharmacology ; Hippocampus ; cytology ; metabolism ; pathology ; Hypertension ; metabolism ; pathology ; physiopathology ; Male ; Neurons ; drug effects ; metabolism ; pathology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Reperfusion Injury ; metabolism

OBJECTIVETo investigate the mechanisms of taurine (Tau) preventive effect on neurotoxicity induced by manganese (Mn) in rat's prefrontal cortex.

METHODSSD rats were divided into four groups after one week of observation: normal control:the group animals received daily intraperitoneal (ip.) injections of sterile saline for 3 months; Mn treated group (Mn): rats received ip. injection of MnCl(2).4H(2)O once a day for 3 months; Tau preventive group (Mn + Tau): The Mn level of this group were the same as Mn's, the Tau level 200 mg/kg, three times per week, for 3 months; Tau treated group (Mn-->Tau): After received the daily injection of Mn as Mn group for 3 months, the rats received Tau three times per week for 3 months. The dose of Mn and Tau were the same as above. The experiment lasted 6 months.

RESULTS(1) Mn induced apoptosis of neurons in rat's prefrontal cortex. The ratio of apoptosis of neurons in the Mn treated group [(20.0 +/- 4.3)%] was higher than that of the control group [(1.8 +/- 2.1)%] (P < 0.05) and the ratio of apoptosis in Tau preventive group (Mn + Tau) was lower than that of the Mn treated group (P < 0.05). (2) The production of MDA in Mn treated group was higher than the control group (P < 0.05) and the activity of SOD was lower than that in the control group. In Tau preventive group (Mn + Tau), Tau increased the activity of SOD and decreased the production of the MDA, with the significant difference level compared to the Mn treated group (P < 0.05).

CONCLUSIONMn induces apoptosis in rat's prefrontal cortex neurons. The main mechanisms of Tau preventing cytotoxicity against Mn is the reduction of the oxidative stress in prefrontal cortex neurons.

Animals ; Apoptosis ; drug effects ; Drug Antagonism ; Male ; Manganese ; toxicity ; Neurons ; drug effects ; metabolism ; pathology ; Neurotoxicity Syndromes ; etiology ; metabolism ; pathology ; prevention & control ; Prefrontal Cortex ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Taurine ; pharmacology

AIMTo observe the impairment of homocysteine (Hcy) on neurons in vitro and the related mechanisms.

METHODSWe examined the consequences of treatment of cultured rat cortical and hippocampal neurons with Hcy and detected the neurons' apoptosis, calcium influx, DNA damage and oxidative injury.

RESULTSPrimary cortical and hippocampal neurons were treated with Hcy (250 micromol/L) for 4 h resulted in apoptosis time-dependently. S-adenosyl methionine (SAM) could significantly, but MK-801, an NMDA receptor inhibitor, couldn't repress the Hcy induced neuron apoptosis. Hcy could induce neuron calcium overload through activating the NMDA receptors. The DNA of neurons was damaged by Hcy because the methylation reactions were inhibited. Hcy treatment also induced MDA level significantly increased, but did not affect the neurons' T-AOC.

CONCLUSIONThese findings indicate that Hcy compromises neuronal homeostasis by multiple, divergent routes, including DNA damage, neuron exitotoxicity, and oxidative injury. Hcy mediated neuron apoptosis was mainly due to DNA damage.

Animals ; Apoptosis ; Calcium ; metabolism ; DNA Damage ; Hippocampus ; drug effects ; pathology ; Homocysteine ; metabolism ; pharmacology ; Neurons ; drug effects ; metabolism ; Oxidative Stress ; Rats ; Rats, Wistar

OBJECTIVETo observe the effect of Shengmaisan on the learning and memory abilities and the expression of nitric oxide synthase and neuron apoptosis in the hippocampus of rats with vascular dementia (VD), and explore the mechanism of Shengmaisan for treatment of VD.

METHODSWistar rats were divided randomly in to normal control group, sham-operated group, VD model group, high-dose Shengmaisan group, low-dose Shengmaisan group, and nimodipine group. In the latter 4 groups, bilateral common carotid artery occlusion (BCCAO) was performed to establish rat models of VD followed by intragastric administration of Shengmaisan at 10 or 30 g.kg(-1).day(-1) or nimodipine at 20 g.kg(-1).day(-1) accordingly. The rats in the control, sham-operated and model groups were given saline in the same manner. The improvement of learning and memory abilities of the rats was assessed using Morris water maze test, and NOS activity and neuronal apoptosis in the hippocampus were determined after the treatment.

RESULTSThe learning and memory ability and hippocampal NOS activity and neuronal apoptosis in low-dose Shengmaisan group and nimodipine group were significantly different from those in the VD model group (P<0.01), but no significant differences were found between high-dose Shengmaisan group and nimodipine group (P>0.05).

CONCLUSIONShengmaisan can significantly improve the learning and memory abilities of VD rats but may not be able to totally reverse the damage. The therapeutic effect of Shengmaisan might be related to its effect in decreasing NOS activity and inhibiting neuronal apoptosis in the hippocampus.

Animals ; Apoptosis ; drug effects ; Dementia, Vascular ; drug therapy ; pathology ; physiopathology ; Drug Combinations ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Hippocampus ; metabolism ; pathology ; Learning ; drug effects ; Male ; Memory ; drug effects ; Neurons ; pathology ; Nitric Oxide Synthase ; metabolism ; Phytotherapy ; Random Allocation ; Rats ; Rats, Wistar

OBJECTIVETo study the effects of intranigral injection of different doses of CuSO4.5H2O on dopaminergic neuron in the nigrostriatal system of rats.

METHODSWistar rats were divided into four groups, including control group, 10 nmol, 50 nmol and 200 nmol copper injected into left substantia nigra (SN) groups. Seven days after the intranigral injection of copper, dopamine (DA) contents in the striatum (Str) were measured by high performance lipid chromotophotography (HPLC); the density of tyrosine hydroxylase (TH) positive axons in the Str was measured by TH staining method; TH and Caspase-3 mRNA expression in the SN were measured by semi-quantitative RT-PCR. We detected the activity of superoxide dismutase (SOD) in the lesioned midbrain of rats using biochemical methods.

RESULTSDA and its metabolites contents had no significant difference between control group and low dose (10 nmol) copper group. But from 50 nmol copper group, DA contents in the lesioned sides were reduced with the increase in the copper doses injected, showing a significant linear correlation (F = 34.16, P < 0.01). In the 50 nmol copper group, TH positive axons in the Str decreased compared with those of the control and unlesioned sides (F = 121.9, P < 0.01). In the 50 nmol copper group, TH mRNA expression decreased (t = 3.12, P < 0.01) while Caspase-3 mRNA expression increased (t = 8.96, P < 0.01) in the SN compared with the control. SOD activity decreased in the midbrain of rats treated with 50 nmol copper compared with that of the control (t = 2.33, P < 0.01).

CONCLUSIONCopper could induce damage of dopaminergic neurons in the SN of rats through destroying antioxidant defenses and promoting apoptosis.

Animals ; Apoptosis ; drug effects ; physiology ; Axons ; drug effects ; metabolism ; pathology ; Caspase 3 ; drug effects ; genetics ; metabolism ; Copper ; toxicity ; Corpus Striatum ; drug effects ; metabolism ; pathology ; Dopamine ; metabolism ; Dose-Response Relationship, Drug ; Male ; Nerve Degeneration ; chemically induced ; metabolism ; pathology ; Neural Pathways ; drug effects ; metabolism ; pathology ; Neurons ; drug effects ; metabolism ; pathology ; Neurotoxins ; toxicity ; Oxidative Stress ; drug effects ; physiology ; Parkinsonian Disorders ; chemically induced ; metabolism ; physiopathology ; RNA, Messenger ; drug effects ; metabolism ; Rats ; Rats, Wistar ; Substantia Nigra ; drug effects ; metabolism ; pathology ; Superoxide Dismutase ; drug effects ; genetics ; metabolism ; Superoxide Dismutase-1 ; Tyrosine 3-Monooxygenase ; drug effects ; genetics ; metabolism ; Wallerian Degeneration ; chemically induced ; metabolism ; pathology

OBJECTIVETo investigate the effect of edaravone on expression of interleukin-1beta (IL-1beta), nuclear factor-kappaB (NF-kappaB) and neuron apoptosis in the juvenile rat hippocampus after status convulsion (SC).

METHODSOne hundred and ninety-five juvenile male Sprague-Dawley (SD) rats were randomly divided into normal saline (NS) control group, status convulsive group and edaravone treatment group. Each group was further divided into five subgroups for different time points. The rats in status convulsive group were kindled into epilepsy by lithium-pilocarpine chemical method. Expressions of IL-1beta and NF-kappaB proteins were detected with immunohistochemistry methods. Expression of NF-kappaB mRNA was detected with reverse transcription-polymerase chain reaction (RT-PCR). The neuron apoptosis was observed by TdT-mediated dUTP nick end labeling (TUNEL).

RESULTS(1) Measured by immunohistochemistry the value of IOD of IL-1beta (30.83 +/- 3.81, 41.00 +/- 5.61, 36.32 +/- 6.78 and 28.48 +/- 4.61, respectively, 12-72 h points) and NF-kappaB (67.60 +/- 5.81, 74.61 +/- 7.94, 82.43 +/- 10.67, 70.70 +/- 5.85 and 68.22 +/- 9.67, respectively, 4-72 h points) positive cells in the SC group increased,there was significant difference compared with NS group (IL-1beta: 11.74 +/- 2.32, 12.93 +/- 2.49, 13.02 +/- 2.83 and 12.98 +/- 5.29, respectively, 12-72 h points. NF-kappaB: 48.67 +/- 16.14, 44.62 +/- 7.82, 53.16 +/- 114.45, 54.27 +/- 5.25 and 55.56 +/- 7.56, respectively, 4-72 h points) (P < 0.01, or P < 0.05). By ED intervention in IL-1beta (22.01 +/- 4.45, 28.28 +/- 4.50 and 26.00 +/- 5.34, respectively, 12-48 h points) and NF-kappaB (58.56 +/- 6.37, 59. 86 +/- 6.73, 70.00 +/- 10.09, 64.78 +/- 7.56 and 64.45 +/- 6.51, respectively, 4-72 h points) positive cells value of the IOD decreased as compared with SC group (P < 0.01, or P < 0.05). (2) Measured by RT-PCR, the expression of NF-KB mRNA and protein trend was similar. (3)The TUNEL positive cells in hippocampus, CA1 of SC group (11.41 +/- 2.37) were more than that of NS group 12 h after the SC (P < 0.01), reached its highest level at48 h (28.78 +/- 5.11), after the intervention with edaravone (8.98 +/- 2.22, 13.09 +/- 2.54 and 20. 57 +/- 4.89, respectively, 12-48 h points) ,TUNEL positive cells showed a significant drop in SC group at 12-48 h time points (P < 0.01, or P < 0.05), but still significantly higher than that of the NS group (6.22 +/- 1.50, 6.57 +/- 1.61 and 6.72 +/- 1.14, respectively) (P < 0.01, or P < 0.05), at the 4 h time point(NS group 6.29 +/- 1.49, SC group 6.61 +/- 1.71, ED group 5.75 +/- 1.41) among the three groups, no significant difference in TUNEL positive cells was found (P = 0.759).

CONCLUSIONSEdaravone inhibited expression of IL-1beta and NF-kappaB in pilocarpine-induced seizures in rat hippocampus, reduced the number of neuronal apoptosis. These results suggest that edaravone may have protective effect against the damage caused by status convulsion.

Animals ; Antipyrine ; analogs & derivatives ; pharmacology ; Apoptosis ; drug effects ; Hippocampus ; drug effects ; metabolism ; pathology ; Interleukin-1beta ; metabolism ; Male ; NF-kappa B ; metabolism ; Neurons ; cytology ; drug effects ; Rats ; Rats, Sprague-Dawley ; Seizures ; metabolism ; pathology

OBJECTIVETo observe the effects of Benzo(a)pyrene (BaP) on apoptosis of neuronal cells and expression of Bcl-2 and Bax proteins and to explore the mechanism of neurotoxicity induced by BaP in rats.

METHODSA total of 32 SD rats were divided randomly into 4 groups, i.e. 3 BaP (126.2, 63.1 and 31.5 µg/kg) groups and a solvent control (50 µg/kg olive oil) group. All rats were exposed to BaP or olive oil by lateral cerebral ventricle micro-injection 1 time a week for 3 weeks. The apoptosis of neuronal cells was detected with TdT-mediated dUTP-biotin nicked labeling (TUNEL) assay and the expression levels of Bcl-2 and Bax were measured with SABC immunohistochemistry in the cerebral cortex and hippocampus tissues of rats.

RESULTSThe results of TUNEL assay showed that apoptosis bodies on the surface of the neurons in the cerebral cortex and hippocampus were clearly observed and the number of apoptosis bodies increased with BaP. Apoptosis indexes (AIs) of the rat cerebral cortex and hippocampus in high exposure group were significantly higher than those in control group (P < 0.05 or P < 0.01). The analysis of immunohistochemistry showed that the Bcl-2 expression levels significantly decreased, the Bax expression levels obviously increased and the ratio of Bcl-2 to Bax decreased in the rat cerebral cortex and hippocampus of medium and high exposure groups, as compared with control group (P < 0.05 or P < 0.01). In the rat cerebral cortex and hippocampus, there were the negative correlation (r = -0.927, P < 0.01; r = -0.934, P < 0.01) between AI and Bcl-2, the positive correlation (r = 0.858, P < 0.01; r = 0.847, P < 0.01) between AI and Bax and the negative correlation (r = -0.939, P < 0.01; r = -0.942, P < 0.01) between AI and Bcl-2/Bax.

CONCLUSIONBaP could induce the apoptosis of neuronal cells in the rat cerebral cortex and hippocampus. Bcl-2 and Bax protein expression may play an important role in the apoptosis of neuronal cells induced by BaP.

Animals ; Apoptosis ; drug effects ; Benzo(a)pyrene ; toxicity ; Brain ; drug effects ; metabolism ; pathology ; Male ; Neurons ; drug effects ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; metabolism