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OBJECTIVE: To study the effect of sub-chronic aluminum exposure on synaptic plasticity in the hippocampus of rats and to explore the mechanism of phosphatidylinositol 3 kinase(PI3 K)/protein kinase B(AKT)/rapamycin target protein(mTOR) signaling pathway. METHODS: Specific pathogen free adult healthy male SD rats were randomly divided into control group and low-, medium-and high-dose groups based on body weight, with 10 rats in each group. Rats were treated with maltol aluminum solution at the concentrations of 0, 10, 20 and 40 μmol/kg body weight by intraperitoneal injection, 5 days per week for 3 months. After the exposure, rats were weighed. Morris water maze was used to test the learning and memory ability, and the two-electrode binding technique was used to record the long-term potentiation(LTP) amplitude in the hippocampus CA1 area of rats. The protein expression of PI3 K, AKT and mTOR in rat hippocampus tissues was detected by Western blot. RESULTS: After the exposure, the body weights of rats in the medium-and high-dose groups were lower than that of the control group(P<0.05). The results of the positioning navigation experiment showed that the escape latencies of the rats in the medium-and high-dose groups were shorter than that in the control group during the 2 nd to 4 th days of the experiment(P<0.05). The results of space exploration experiments showed that there was no statistical difference on the target quadrant retention time and the number of crossing the platform among the 4 groups(P>0.05). At 1, 30, and 60 min after high-frequency stimulation, the LTP amplitudes in the hippocampus CA1 area of the aluminum-treated groups were lower than that of the control group at the same time point(P<0.05), and the LTP amplitudes of hippocampus CA1 area of rats decreased with the increase of maltol aluminum exposure dose(P<0.01). The relative expression of PI3 K, AKT and mTOR protein in the hippocampus tissues of the aluminum-treated groups was lower than that of the control group(P<0.05), and the relative expression of the above three proteins decreased with the increase of the maltol aluminum exposure dose(P <0.01). CONCLUSION: Sub-chronic aluminum exposure could lead to dose-dependent inhibition of hippocampus synaptic plasticity in rats, thereby impairing the spatial learning ability of rats. This process may be related to inhibition of PI3 K/AKT/mTOR signaling pathway by aluminum.
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OBJECTIVE: To observe the effect of maltolate aluminum on synaptic plasticity in the hippocampus of rats and to explore the regulatory effect and mechanism of metabotropic glutamate receptor 1(mGluR1). METHODS: Specific pathogen free healthy adult male SD rats were randomly divided into control group, aluminum group, aluminum agonist group and aluminum antagonist group, 8 rats in each group. The rats in the control group received no treatment; the rats in aluminum group were injected with 5 μL 10 mmol/L maltolate aluminum solution into the lateral ventricle; the rats in aluminum agonists and aluminum antagonist group were injected with 3 μL 10 mmol/L maltolate aluminum solution plus 2 μL 0.1 μmol/L mGluR1 agonist or 2 μL 0.2 μmol/L mGluR1 antagonists into the lateral ventricle, respectively.Maltolate aluminum solution was injected every 2 days and continued for 10 days. After maltolate aluminum exposure, the amplitudes of long-term potentiation(LTP) in hippocampal CA1 region of rats were measured, and the relative expression levels of mRNA and protein of mGluR1, N-methyl-D-aspartate receptor(NMDAR1) and protein kinase C(PKC) in hippocampus tissue of rats were detected by real-time fluorescence quantitative polymerase chain reaction and Western blotting. RESULTS: The amplitude of LTP in hippocampal CA1 region in aluminum group and aluminum agonist group was lower than that in the control group and the aluminum antagonist group(P<0.05). Compared with the control group, the relative expression of mGluR1 mRNA and protein in the aluminum group increased, the relative expression of PKC and NMDAR1 mRNA and protein in the aluminum group decreased(P<0.05). Compared with the aluminum group, the relative expression of mGluR1 mRNA and protein in the aluminum agonist group increased, while the NMDAR1 mRNA decreased(P<0.05); the relative expression of mGluR1 mRNA and protein in the aluminum antagonist group decreased, while the NMDAR1 mRNA and protein increased(P<0.05). Compared with the aluminum agonist group, the relative expression of mGluR1 mRNA and protein decreased, while the NMDAR1 mRNA and protein increased in the aluminum antagonist group(P<0.05). The relative expression level of PKC mRNA and protein in aluminum agonist group and aluminum antagonist group was not statistically significant(P>0.05), and there was no statistical significance in these two groups compared with control group and aluminum group(P>0.05). CONCLUSION: Maltolate aluminum exposure can inhibit synaptic plasticity by inhibiting LTP in hippocampus of rats, and the mechanism may be related to the regulation of NMDAR1 expression by mGluR1.
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Objective@#To explore the association between polycyclic aromatic hydrocarbons (PAHs) exposure and cytochrome P450 CYP1A1 expression at gene and enzyme activity levels in the peripheral blood monocyte cells in coke oven workers, and to provide a certain basis for the biological monitoring of health damage in coke oven workers.@*Methods@#We surveyed 118 coke oven workers and 63 controls (energy power workers in the same company) using self-designed questionnaire, determined their post-shift urinary 1-hydroxypyrene (1-OH-Py) concentration using high performance liquid chromatography (HPLC)-fluorescence detector method. We also isolated the peripheral blood mononuclear cell (PBMC) from fasting venous blood, and detected DNA damage using comet assay, CYP1A1 mRNA level using the real-time fluorescent quantitative PCR (FQ-PCR), and EROD activity using spectrophotometry. Statistical analyses including one-way analysis of variance and multiple linear regressions were used to analyze the association of urinary 1-OH-Py and CYP1A1 mRNA level and EROD activity.@*Results@#Compared to the control group, the urinary 1-OH-Py concentration and PBMC DNA tail moment were significantly increased in coke oven workers (P<0.05), and CYP1A1 gene level and EROD activity in PBMC were significantly decreased (P<0.05). Multiple linear regression showed that a ten-fold increase of urinary 1-OH-Pycon centration was associated with a decrease of 0.77 (95%CI: -1.33--0.21) in CYP1A1 gene level, and a decline of 0.15 (95%CI: -0.76--0.16) in EROD activity of PBMC in coke oven workers (P<0.05).@*Conclusion@#Occupational PAHs exposure induced DNA damage, which was associated with the decreased level in CYP1A1 gene cavel and EROD activity in PBMC of coke oven workers.
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OBJECTIVE: To investigate the relationship of polycyclic aromatic hydrocarbons( PAH) metabolites,DNA oxidative damage and ring finger protein 2( RING2) expression in coke oven workers. METHODS: A judgment sampling method was used to select 497 coke oven workers in a steel plant as exposure group and 175 water treatment workers in the same plant as control group. The levels of urinary 1-hydroxypyrene, 2-hydroxynathalene, 2-hydroxyfluorene,9-hydroxyphenanthrene and 8-hydroxy deoxyguanosine(8-OHd G) were detected by high performance liquid chromatography.The RING2 expression in whole blood was measured by reverse transcription-polymerase chain reaction. RESULTS: The relative expression of urinary 1-hydroxypyrene,2-hydroxynathalene,2-hydroxyfluorene,9-hydroxyphenanthrene and RING2 in exposure group were higher than that in control group( P < 0. 01). The logistic regression analysis indicated that the higher the level of 1-hydroxypyrene,the higher the risk of high-RING2 expression( P < 0. 05) after adjusting for factors such as sex,age,smoking status,alcohol drinking,2-hydroxynathalene,2-hydroxyfluorene and 9-hydroxyphenanthrene.In 1-hydroxypyrene middle and high level groups,the 8-OHd G concentration of high-RING2 expression workers was significantly higher than those of low-RING2 expression workers( P < 0. 05). CONCLUSION: With the increase of urinary1-hydroxypyrene,the risk of high-RING2 expression was elevated,the degree of DNA oxidative damage was gradually increased.
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Objective:To investigate the relationship between visfatin and insulin resistance (IR)of type 2 diabetes mellitus(T2DM) through the classic insulin signaling pathway phosphatidy inositol-3 kinase (PI3K).Methods:The human T2DM preadipocyte cells were recoveried, extended and differentiated.The visfatin overexpression vectors were built, transformated, cultivated and extracted.The fat cells were transfected with different overexpression levels (0.0, 1.0, 2.5 and 5.0 μg);0.0 μg group was used as control group,and the remaining three groups as observation groups.The mRNA expression levels of visfatin, insulin receptor substrate-1(IRS-1), insulin receptor substrate-2(IRS-2) and PI3K (P85α) were detected by Q-PCR.The protein expression levels of visfatin, IRS-1, IRS-2, PI3K (P85α), IRS-1 and IRS-2 phosphorylation levels were measured by Western blotting method.The glucose uptake rates of fat cells were determined by [3H]-2-deoxidation-D-glucose uptake assay.Results:The expression levels of visfatin mRNA and protein in various groups were increased with the increase of transfection concentration gradient (P0.05).The glucose uptake rates of fat cells were elevated with the increasing of visfatin expression (P<0.05).Conclusion:The visfatin overexpression of fat cells in vitro can increase the expression levels of IRS-1 and PI3K.
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Objective To observe the change of serum Omentin-1 in gestational diabetes mellitus(GDM)and to investigate its clinical significance.Methods Serum Omentin-1 level was detected in 85 cases of GDM and 85 matched cases of normal glucose tol-erance(NGT)by ELISA,the glycolipids biochemical indexes,inflammation indexes and fasting insulin (FINS)level were simultane-ous detected,then the insulin resistance index (HOMA-IR)was calculated in both groups.Results The levels of prenatal prepreg-nant BMI,FPG,hs-CRP,blood lipids,blood glucose,FINS and HOMA-IR in the GDM group were significantly higher than those in the NGT group,while serum Omentin-1 level was obviously lower than that in the NGT group,difference was statistically signifi-cant (P<0.05);when prenatal obesity and/or HOMA-IR≥2,the serum Omentin-1 levels was significantly decreased.Serum Omentin-1 level had significant positive correlation with HDL,and negative correlation with prepregnant BMI,prenatal BMI,FPG, FINS and HOMA-IR.The multiple stepwise regression analysis showed that prepregnant BMI,TG,FPG and FINS were independ-ent influencing factors of serum Omentin-1 in GDM.Conclusion Serum Omentin-1 is associated with GDM closely,which can re-flect the degrees of sugar,lipid metabolic disorder and insulin resistance in pregnant women,and may be involved in the occurrence and development of GDM.
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Objective To establish a gestational diabetes rat model by feeding the rats with high-fat diet.Methods A total of 55 female SD rats were divided into four groups:NV group,NP group,FV group and FP group.Three months after normal feeding,the female rats in NP and FP group were put into the same cage with the male rats at the ratio of 2∶1 and were given high-fat diet or normal diet as usual.Before pregnancy and day 1,7,14,20 in pregnancy,fasting plasma glucose and body weight of rats were detected.The fasting serum insulin and serum c-peptide levels were monitored by enzyme immunoassay and insulin resistance index was calculated.At late pregnancy,glucose tolerance and the indicator of fat were tested.Liver and pancreas were dyed to be observed under microscope.FResultS Body weights of the rats raised with high-fat diet were significantly higher than those of control group and body weight during pregnancy significantly increased (P＜0.05).Fasting glucose,fasting insulin and serum C-peptide in FP group were signifieantly higher than those in NP group and insulin resistance was evident (P＜0.05).The area under curve of GTT in FP group was significantly larger (P＜0.05).The levels of serum lipids in FP group were higher than those in normal group.CorncluSiornS The gestational diabetes rat model induced by high-fat diet can be successfully established.The model presents major pathophysiological manifestations of GDM and can be used as a good model of GDM in relevant research.
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Objective To investigate the relationship between Vaspin and GDM insulin resistance. Methods The GDM preadipocyte cells were recoveried, extended and differentiated.Vaspin overexpression carriers were made to transformate, cultivate and extract the plasmid. The fat cells were transfected and extended using 4 overexpression levels (0.0 μg, 1.0 μg, 2.5 μg, 5.0 μg). Q-PCR was used to detect mRNA expression of Vaspin, insulin receptor substrate-1/2 (IRS-1/2), phosphatidy inositol 3 kinase (PI3K (P85a) Western Blot was used to detect protein expression of Vaspin, IRS-1/2, PI3K (P85a) and IRS-1/2 phosphorylation levels, and [3H]-2-deoxidation-D-glucose uptake assay was used to detecte glucose uptake rates. Results (1) According to the Q-PCR and WB results, the constructed Vaspin overexpression carrier was effective; (2) With the Vaspin expression increased, the mRNA and protein expression of IRS-1/2, PI3K (P85a) and IRS-1/2 tyrosine phosphorylation levels had no significant changes;(3) Glucose uptake rate of fat cells had no obvious correlation with Vaspin. Conclusion High expression of Vaspin in GDM serum and omental adipose tissue has no obvious link with the insulin resistance of GDM.
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<p><b>OBJECTIVE</b>To explore the role of P53 phosphorylation in neuron apoptosis of rats by chronic aluminum exposure.</p><p><b>METHODS</b>A 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.</p><p><b>RESULTS</b>Tunel 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).</p><p><b>CONCLUSION</b>Chronic 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.</p>