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Objective:To observe the expression levels of glial fibrillary acidic protein (GFAP), β-tubulin Ⅲ and synaptophsin, and explore the role of tripartite synapse in the mechanism of central nervous system (CNS) injury and the neuroprotective effect of chondroitin sulfate (CS).Methods:One month old clean grade, 48 female Sparague-Dawley rats and 48 male Sparague-Dawley rats, were randomly divided into 8 groups according to body weight (90 - 120 g) by random number table method, with 12 rats in each group, half male and half female. These rats were fed with water containing different concentrations of sodium fluoride (NaF) [ < 0.5 mg/L (control, CN), 10.0 mg/L (low dose fluoride, LF) and 50.0 mg/L (high dose fluoride, HF)]. Some rats were fed directly for 185 days (CN, LF and HF groups). In addition, rats of CN + normal saline (NS), LF + NS, HF + NS groups and LF + CS, HF + CS groups, were intraperitoneally injected with NS or 0.66 mg/kg CS for 5 consecutive days after 180 days of feeding. After the experiment, the pathological changes of hippocampal CA4 of brain tissue in each group were observed by hematoxylin eosin staining under light microscope, and the expression and distribution of GFAP, β-tubulin Ⅲ and synaptophsin in hippocampal CA4 of rats were detected by immunohistochemistry, the expression of GFAP, β-tubulin Ⅲ and synaptophsin at protein level in hippocampus of rats were detected by Western blotting.Results:Under light microscope, eosinophilic change, loss and irregular arrangement of neuron in the hippocampal CA4 were observed in LF, HF, LF + NS and HF + NS groups. The morphology of LF + CS and HF + CS groups was not significantly changed compared with CN group, but was significant changed compared with LF, HF, LF + NS and HF + NS groups. Immunohistochemical results showed that the rates of positive area of GFAP, β-tubulin Ⅲ and synaptophsin in female and male rats in LF and HF groups were significantly decreased than those in CN group ( P < 0.05); the positive area rates of female and male rats in LF + CS and HF + CS groups were higher than those in LF and HF groups, respectively ( P < 0.05). Western blotting results showed that the proten expression levels of GFAP, β-tubulin Ⅲ and synaptophsin of female and male rats in LF and HF groups (LF group: 0.90 ± 0.09, 0.82 ± 0.08, 1.43 ± 0.14, 0.92 ± 0.02, 1.21 ± 0.15, 0.87 ± 0.02, HF group: 0.58 ± 0.14, 0.73 ± 0.03, 0.63 ± 0.06, 0.67 ± 0.03, 0.87 ± 0.04, 0.70 ± 0.05) were lower than those in CN group (1.24 ± 0.08, 1.09 ± 0.10, 2.64 ± 0.30, 1.54 ± 0.09, 1.72 ± 0.10, 1.13 ± 0.06, P < 0.05). Conclusions:The tripartite synapse and extracellular matrix may take part in pathogenesis of the damages of CNS results from chronic fluorosis; CS may reduce the injury to a certain extent.
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Objective To study the mechanism of central nervous system (CNS) injury in chronic fluorosis and the neuroprotective effect of chondroitin sulfate (CS).Methods Forty-eight female Sprague-Dawley rats weighting 90-120 g were divided into 8 groups according to body weight by random number table,6 rats in each group:control group,drinking tap water freely;low dose and high dose fluoride groups,freely drinking tap water with fluoride content of 10 and 50 mg/L,respectively;control + normal saline (NS),low dose fluoride + NS,and high dose fluoride + NS groups,each group was fed for 180 d,and treated with intraperitoneal injection of 0.66 mg/kg NS for 5 d (once a day);low dose fluoride + CS and high dose fluoride + CS groups,each group was fed for 180 d,0.66 mg/kg CS was injected intraperitoneally for 5 d (once a day).All groups were fed standard nutritive animal feed for 185 d and dissected for brain tissue.The pathologic change was observed after hematoxylin-eosin (HE)staining;the expression levels of phosphorylated extracellular signal-regulated protein kinase 1/2 (phospho-Erk1/2)and glutamate receptors 1,2 (GluR1,GluR2) in the brain cortex were detected by immunohistochemistry;the protein levels of Erk1/2,phospho-Erk1/2,GluR1,and GluR2 in the brain cortex were detected by Western blotting.Results Brain cortex of all rats in the fluoride groups showed eosinophilic degeneration,loss and disordered arrangement of neurons,and the brain morphological changes in each fluoride + CS groups were significantly improved compared with those in the fluoride groups.Immunohistochemistry results showed that compared with the control group [(0.44 ± 0.09)％,(1.49 ± 0.05)％,(2.51 ± 0.54)％],the expression levels of phospho-Erk1/2 [(1.47 ±0.09)％,(1.03 ± 0.05)％],and GluR2 [(2.37 ± 0.06)％,(3.38 ± 0.12)％] in the low dose and high dose fluoride groups were increased,and the expression levels of GluR1 [(1.49 ± 0.02)％,(0.99 ± 0.19)％] were decreased (P ＜ 0.05).Western blotting results showed that compared with the control group (1.00 ± 0.12,1.76 ± 0.33),the protein levels of Erk1/2 (3.10 ± 0.76,1.99 ± 0.01) and phospho-Erk1/2 (3.27 ± 0.25,2.67 ± 0.05) in low dose and high dose fluoride groups were significantly increased (P ＜ 0.05);compared with low dose fluoride group,the protein levels of Erk1/2,and phospho-Erk1/2 (1.30 ± 0.31,2.20 ± 0.34) in low dose fluoride + CS group decreased significantly (P ＜0.05).Compared with control group (1.86 ± 0.47,1.17 ± 0.27),the protein levels of GluR1 (1.09 ± 0.26,0.61 ± 0.14) in low dose and high dose fluoride groups decreased significantly,while the protein level of GluR2 (1.99 ± 0.42,3.38 ±0.27) increased significantly (P ＜ 0.05);compared with low dose and high dose fluoride groups,the protein levels of GluR2 in low dose fluoride + CS and high dose fluoride + CS groups (1.53 ± 0.41,2.65 ± 0.32) decreased significantly (P ＜ 0.05).The protein level of phospho-Erk1/2 was negatively correlated with GluR1 protein level (r =-0.975,-0.991,P ＜ 0.05) in low dose and high dose fluoride groups,and it was positively correlated with the protein level of GluR2 (r =0.986,0.993,P ＜ 0.05).Conclusion The CNS injury caused by chronic fluorosis may be related to GluR1 and GluR2 activated Erk1/2 signaling pathway,and CS has certain protection to the injury.
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Objective To estimate the value of team-based learning ( TBL ) in the teaching of occupational health and occupational medicine for foreign students. Methods 42 foreign students from the majorofclinicalmedicineinHarbin Medical UniversitywereselectedtoformtheTBLdiscussiongroup. Before class, teachers assigned tasks, and the students were taught with the same teachers with TBL teaching method. The effect of learning was evaluated by questionnaire and classroom test. The t test was performed using SPSS 19.0 statistical software for comparison of the results of individual test and group test. Results The result of the questionnaire showed that students agreed that TBL teaching can improve students' interest, self-study ability and broaden their learning ideas. The classroom test results showed that after the TBL discussion, the test scores of occupational oncology and pneumoconiosis were significantly higher than those of individual test. The difference was statistically significant (P<0.05). Conclusion The TBL method can significantly improve the students' comprehension of knowledge and enhance their learning effect.
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Objective@#To study the protective effect of Ascorbic acid (AA) on the injury of nickel-exposed mouse embryonic fibroblasts (NIH/3T3) .@*Methods@#A model of damage induced by 50 μg/mL nickel refining dust was established to determine the relative survival rate of cells, superoxide dismutase (SOD) , lactate dehydrogenase (LDH) and glutathione peroxidase. (GSH-Px) activity, hydrogen peroxide (H2O2) and malondialdehyde (MDA) content, and p53 (wild-type) , Bcl-2 protein expression. To investigate the protective effect of different doses of ascorbic acid (25, 50, 100 mmol/L) on nickel-refined dust-induced NIH/3T3 cell injury.@*Results@#The study showed that ascorbic acid Ⅲ group can make the NIH/3T3 cell survival rate increased significantly; Apoptosis rate was reduced; The vitality of SOD and GSH-Px increased significantly, and the difference was statistically significant (P<0.05) . At the same time, the level of MDA and H2O2 and the activity of extracellular LDH enzyme were significantly reduced, and the difference was statistically significant (P<0.05) . The results showed that nickel refining dust induced cell damage through up-regulation of p53 protein and down-regulation of Bcl-2 protein expression; ascorbic acid interventions, the expression level of Bcl-2 protein in ascorbic acid II and III groups was higher than that of nickel refining dust group, and the difference was statistically significant (P<0.05); The expression level of p53 protein in each dose group of ascorbic acid was lower than that of nickel refined dust group, and the difference was statistically significant (P<0.05).@*Conclusion@#With the increase of concentration of ascorbic acid, oxidative damage levels, antioxidant enzyme levels, reduce cell apoptosis, reduce expression of p53, increased expression of Bcl-2. It showed that ascorbic acid had protective effect on NIH/3T3 cell injury induced by nickel refining dust.
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Objective To investigate the changes of extracellular regulated protein kinases (Erk)1/2,phospho-Erk1/2,matrix metalloproteinases (MMP)-2 and MMP-9 in rats with experimental chronic fluorosis and the role of chondroitin sulfate in treatment of rat with experimental chronic fluorosis.Methods Using a group design and cell culture methods,the SH-SY5Y cells were divided into control group (culture medium with 0.0 mmol/L fluoride ion),fluoride group (fluoride ion:4.0 mmol/L) and chondroitin sulfate group (fluoride ion:4.0 mmol/L,chondroitin sulfate:0.4 g/L).The ultrastructural changes of the SH-SY5Y cells were observed through electron microscope after 24 h treatment.The SH-SY5Y cells were cultured for 72 h,the number of cells survived in three groups.were detected after stained by trypan blue.Fifteen clean grade SD rats with body weight of 100-120 g were divided into control group (tap water:fluorine content less than 0.5 mg/L),fluoride group (fluoride ion:10.0 mg/L) and chondroitin sulfate group (fluoride ion:10.0 mg/L,the rats were performed intraperitoneal injection with 0.66 mg/kg chondroitin sulfate for 5 days after intaking fluoride for 90 days) on the basis of random number table.Five rats were in each group,and the experiment was carried out for 95 days.The capability of learning and memory of rats were tested by Morris water maze test;the expression of phospho-Erk1/2,Erk1/2,MMP-2 and MMP-9 protein in brain tissue was detected by Western blotting;the expression of phospho-Erk1/2,MMP-2 and MMP-9 in hippocampus CA2 area of brain was detected by immunohistochemistry.Results More vesicles and swelling of mitochondria or endoplasmic reticulum were observed in SH-SY5Y cell treated with fluoride through electron microscope,but relatively less in chondroitin sulfate group.Survival rate and amount of SH-SY5Y treated with chondroitin sulfate [(92 ± 23)％ and (7.83 ± 1.38) × 106/ml] were significantly higher than that of fluoride group [(55 ± 2)％,(2.19 ± 1.26) × 106/ml,P ＜ 0.05].Animal experiment results showed that most rats in control group and chondroitin sulfate group used spatial direct search strategy,and the amount of this search strategy (2.20 ± 1.09,3.40 ± 1.34) was more than that in fluoride group (0.40 ± 0.54,P ＜ 0.05).The expression of phospho-Erk1/2 in brain tissue of rats in fluoride group (3.26 ± 0.88) was significantly higher than that in control group (1.53 ± 0.28) and chondroitin sulfate group (2.36 ± 0.87,P ＜ 0.05).Immunohistochemistry results showed that average gray value of phospho-Erk1/2 in chondroitin sulfate group (220.20 ± 3.09) was significantly higher than that of the control group and the fluoride group (100.00 ± 0.00,130.98 ± 1.27,P ＜ 0.05).The average gray value of MMP-2 in the fluoride group (294.52 ± 5.18) was significantly higher than that in control group and chondroitin sulfate group (100.00 ± 0.00,117.95 ± 1.55,P ＜ 0.05).The average gray value of MMP-9 protein of the fluoride group (993.64 ± 3.66) and the chondroitin sulfate group (1 167.30 ± 239) was significantly higher than that of control group (100.00 ± 0.00,P ＜ 0.05).Conclusions Erk1/2 pathway possibly maintains the stability of cell survival by regulating the expression of MMP-2 and MMP-9.Chondroitin sulfate can protective nerve cells and reduce the nervous damage caused by fluorosis to some certain extent.
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Objective To assess the diagnostic value of 3.0T magnetic resonance imaging (MRI) and ultrasonic cardiography in women with high altitude pulmonary arterial hypertension (PAH). Methods Seventy-six women with high altitude PAH treated at our hospital were divided into either an MRI group (group A) or an ultrasonic cardiography group (group B), with 38 cases in each group. Fifty healthy women from high altitude areas were enrolled as a control group (group C). Group A underwent MRI examination alone, Group B underwent ultrasonic cardiography examination alone, and Group C underwent concomitant MRI and ultrasonic cardiography examinations. Diagnosis accuracy and diagnostic results were compared among different groups. Results Compared with group B, diagnosis accuracy significantly rose in group A (P < 0.05). MRI showed that except right ventricular end diastolic transverse diameter,left atrial diameter, aortic diameter, and right ventricular end systolic transverse diameter, other indexes differed significantly between groups A and C (P < 0.05). Ultrasonic cardiography showed that the SPAP of group B was (44.5 ± 8.6) mmHg. Right ventricular outflow tract, pulmonary artery, right ventricular inner diameter, right atrial inner diameter, right ventricle anterior wall, interventricular septal thickness, right ventricular Tei index, and right ventricular ejection fraction differed significantly between groups B and C (P<0.05), although there was no significant difference in LVEF or LV-Tei between the two groups (P>0.05). Conclusion Both MRI and ultrasonic cardiography can diagnoses high altitude PAH in women effectively. MRI can accurately evaluate the heart structure and function in women with high altitude PAH, representing a more efficient diagnostic method.
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<p><b>OBJECTIVE</b>To investigate the cytotoxicity and oxidative damage on NIH/3T3 cells induced by nickel smelting fume.</p><p><b>METHODS</b>NIH/3T3 cells were treated with nickel smelting fume collected from a nickel smelting factory in China with doses of 0, 6.25, 12.50, 25.00, 50.00, and 100.00 µg/ml for 6 h. Dose-dependent cytotoxicity in cells were assessed by Cell Counting Kit-8 (CCK-8), natural red uptake assay, and lactate dehydrogenase (LDH) leakage assay, and the level of oxidative damage was assessed based on the activity of catalase (CAT), percentage inhibition of superoxide dismutase (SOD), and content of malonaldehyde (MDA).</p><p><b>RESULTS</b>The relative survival of NIH/3T3 cells decreased with the increase in the dose of nickel smelting fume. In the CCK-8 assay, the group with 100 µg/ml nickel smelting fume showed a cell growth inhibition rate of 86%, with a significant difference compared with the control group (P < 0.05). LDH activity increased with increasing dose of nickel smelting fume: the groups of 12.50, 25, 50, and 100 µg/ml nickel smelting fume all showed increased LDH activities as compared with the control group (P < 0.05). The activities of CAT were significantly reduced in groups of 25, 50, and 100 µg/ml nickel smelting fume as compared with that of the control group (P < 0.05). As the dose of nickel smelting fume increased, the percentage inhibition of SOD and the content of MDA increased, with significant differences compared with the control group (P < 0.05).</p><p><b>CONCLUSION</b>Oxidative damage may be induced in NIH/3T3 cells after 6 h of exposure to nickel smelting fume, which leads to cell death.</p>
Subject(s)
Animals , Mice , Catalase , Metabolism , Cell Death , Dust , L-Lactate Dehydrogenase , Metabolism , Malondialdehyde , Metabolism , Metallurgy , NIH 3T3 Cells , Nickel , Toxicity , Oxidative Stress , Superoxide Dismutase , MetabolismABSTRACT
Sixty-two adult rats were employed, 8 of them served as controls and the remainderwere exposed to whole body X-irradiation in a single dose of 500 r. The animals weresacrificed at intervals of 2, 6, 12 hours and 1, 3, 6, 10, 20, 30 days after irradiation.Specimens of the spleen were obtained from both the experimental and control groups forhistological and histochemical examinations. The data indicate that: 1. A marked decrease in the spleen size and in the number of its Malpighian cor-puscles, and a severe destruction of its architecture with an extensive necrosis of lympho-cytes, occurred within 24 hours after irradiation. Regeneration began on the 6th day andthe spleen became almost normal at the end of the 30th day. Among the various cell-types of the spleen, the radiosensitivity was highest in the lymphocytes and lowest in theplasma cells. The reticular cells were apparently injured during the early stage afterirradiation, though they belonged to the radioresistant series. 2. The decrease in staining intensity of both desoxyribose-and ribose nucleic acidsof the spleen started as early as 2 hours after irradiation and continued to reach itsmaximum in a period of 1--3 days. This result was produced not only by the depletionin cell population, but also by the decrease in nucleic acid content of individual cells. 3. A marked increase in the activity of nonspecific alkaline phosphatase and ade-nosine triphosphatase occurred within 24 hours and it returned gradually to normal fromthe 3rd day to the 10th day after irradiation. 4. There was no significant change in the amount of protein-bound SH-groups ofvarious cell-types of the spleen in each post-irradiation period. 5. No difference was found in the changes produced by irradiation between theanimals fed with normal diet and those fed with phospholipides in addition.
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The properties and functions of mouse pluripotential stem cells (CFU-S) were studied with spleen colony technique and other related methods. The data expressed that there is a linear relationship between the number of transplanted marrow cells and the number of spleen colonies that developed. Among various hematopoietic tissues, bone marrow is the richest source of CFU-S. Spleen and peripheral blood also contain a few of such cells. The percentages of CFU-S in these organs are 0.7%, 0.05% and 0.01% in sequence. No CFU-S can be found in thymus or lymph nodes. Under normal conditions, most of the CFU-S are in G_o phase with a small proportion (6.7%) in S phase.Self-renewing capacity, an important hematopoietic function of CFU-S, was measured by the experiments of single spleen colony retransplantation. The value of the probability of self-renewal, p, is calculated as 0.76. CFU-S has an active ability of migration. It was found that a number of CFU-S either from the marrow cell suspension injected intraperitoneally or from an entire encapsulated spleen which was placed free in the peritoneal cavity after ligation of its blood vessels can penetrate through a lot of barriers to develop spleen colonies in the lethally irradiated mice. A dose of 500～700 rad ?-irradiation apparently stimulates the CFU-S migrating from bone marrow to circulation.