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Objective:To investigate the effects of fluoride exposure on proliferation, apoptosis and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in mice.Methods:BMSCs were isolated and cultured from femur bone marrow of C57BL/6 mice (6 - 8 weeks). The cells in passage 3 were used to detect the surface markers of stem cells by flow cytometry. The cells were cultured in media with a final fluoride concentration of 0.0, 0.1, 1.0, 5.0, 10.0, 15.0, 20.0 and 40.0 mg/L, respectively. The effects of different fluoride concentrations on BMSCs cell proliferation (CCK8 method), apoptosis (flow cytometry analysis), osteogenic differentiation ability [alizarin red and alkaline phosphatase (ALP) staining] were detected. Western blot was applied to detect the levels of apoptosis-related proteins [poly ADP-ribose polymerase (PARP)], mitogen-activated protein kinase (MAPK) pathway member proteins [extracellular regulated protein kinase 1/2 (ERK1/2), c-Jun amino-terminal kinase (JNK), p38 and phosphorylated ERK, JNK, p38 (p-ERK, p-JNK, p-p38)], osteogenic differentiation-related protein [Runt-related transcription factor 2 (Runx2), ALP] and Wnt/β-catenin pathway member proteins [glycogen synthase kinase-3β (GSK3β), phosphorylated GSK3β (p-GSK3β) and β-catenin]. Immunocytofluorescense staining was applied to evaluate the expression levels of p-GSK3β and β-catenin. The two pathways (MAPK and Wnt/β-catenin) were blocked by SP600125 and DKK-1, respectively, to testify their involvement in mechanisms of apoptosis and osteogenic differentiation.Results:The mouse BMSCs were successfully isolated and cultured. Flow cytometry analysis showed that the mesenchymal stem cell surface biomarkers (CD73, CD90 and CD105) were positively expressed. The comparison of cell proliferation at three time points (24, 48 and 72 h) in each concentration group was statistically significant ( F = 65.36, 160.04 and 365.32, P < 0.001), and the comparison of early apoptosis (24 h) in each concentration group was statistically significant ( F = 214.04, P < 0.001); compared with the 0.0 mg/L group, the cell proliferation in 15.0, 20.0 and 40.0 mg/L groups decreased, and the early apoptosis rate in 10.0, 15.0 and 20.0 mg/L groups increased ( P < 0.05). When cells were treated with 15.0 mg/L fluoride for 0 - 24 h, the p-JNK/JNK ratio was higher at 2, 4, 8, 12, 18 and 24 h compared with that at 0 min ( P < 0.05); compared with the fluoride group (15.0 mg/L), the early apoptosis rate of cells after SP600125 block decreased ( P < 0.05), and the protein expression levels of PARP and p-JNK decreased ( P < 0.05). After osteogenic induction, compared with the 0.0 mg/L group, in 0.1 and 1.0 mg/L groups ALP staining was enhanced and the number of calcified nodules increased, and the protein expression levels of Runx2 and ALP in the 0.1 and 1.0 mg/L groups were higher ( P < 0.05). After osteogenic induction, compared with the 0.0 mg/L group, the p-GSK3β/GSK3β ratio and β-catenin protein level were significantly higher in the 0.1 and 1.0 mg/L groups ( P < 0.05); and compared with the fluoride group (1.0 mg/L), addition of DKK-1 significantly decreased the protein expression levels of p-GSK3β and β-catenin and reduced the nuclear entry of β-catenin, and ALP staining decreased and the number of calcified nodules decreased. Conclusions:High concentration of fluoride (> 10.0 mg/L) inhibits the proliferation and promotes apoptosis of BMSCs, while low concentration of fluoride (0.1, 1.0 mg/L) promotes osteogenic differentiation. The MAPK/JNK pathway and the classical Wnt pathway are involved in the above cellular processes, respectively.
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Objective:To evaluate the effects of comprehensive reform of clinical education on cultivating the clinical thinking ability of medical students in internal medicine.Methods:A total of 44 clinical interns on medicine rotation were included in this study and divided into experimental group and control group, and a series of measures for clinical teaching reform, which included undergraduate tutorial system, team-based learning (TBL) mode, combination of electronic medical record and handwritten medical record, as well as formative assessment, were applied to fully promote clinical thinking ability of medical students. SPSS 17.0 software was used to compare the scores of final academic tests of rotation and competition of medical record writing between the control and the experiment groups. Self-designed questionnaires on undergraduate tutors and clinical interns were applied to comprehensively evaluate the effects of this education reform.Results:Independent-sample t tests showed there were statistically significant difference ( P<0.01) in the scores of final academic tests of rotation and competition of medical record writing between the two groups, and the mean score of the experiment group was higher than that of the control group. Questionnaire survey showed that tutors and clinical interns both fully affirmed the positive effects of the education reform on cultivating clinical thinking ability of medical students in internal medicine. Conclusion:Application of comprehensive education reform in clinical teaching of internal medicine, which based on introduction of undergraduate tutorial system and TBL mode, could effectively promote the clinical thinking ability of medical students and the teaching quality.
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Objective@#To investigate the effects of p38 mitogen-activated protein kinases (p38 MAPK) inhibitor (SB203580) on airway inflammation in a mouse model of asthma.@*Methods@#Forty-eight female BALB/c mice were randomly divided into four groups (n=12): control group, asthma group, dexamethasone group (2 mg/kg) and SB203580 group (5 mg/kg). Within 24 hours after the last ovalbumin (OVA) challenge, airway responsiveness was measured by lung resistance (RL) and dynamic compliance (Cdyn). Bronchoalveolar lavage fluid (BALF) was collected for counting total cells, eosinophils, lymphocytes, neutrophils and macrophages. IgE and OVA-specific IgE in serum and IL-4, IL-5, IL-13 and IFN-γ in BALF were detected by ELISA. Lung tissues were stained with hematoxylin and eosin (HE) and alcian blue-periodic acid-Schiff (AB-PAS) to observe histopathological changes. Expression of p38 MAPK and phosphorylated p38 (p-p38) MAPK was detected by immunohistochemical staining and Western blot, respectively.@*Results@#(1) The mice in the asthma group showed typical symptoms of acute asthma after inhaling aerosolized OVA, while the symptoms were alleviated in those treated with dexamethasone or SB203580. (2) When challenged with the methacholine at the doses of 0.050 mg/kg, 0.100 mg/kg and 0.200 mg/kg, asthmatic mice treated with dexamethasone or SB203580 showed significantly decreased RL and increased Cdyn as compared with those in the asthma group (all P<0.05). (3) The concentrations of total IgE and OVA-specific IgE in serum in both dexamethasone and SB203580 groups were lower than those in the asthma group (all P<0.05). (4) Compared with the asthma group, the numbers of the total cells, eosinophil, lymphocytes and neutrophils in BALF were decreased in dexamethasone and SB203580 groups (all P<0.05). (5) Compared with the asthma group, the dexamethasone and SB203580 groups showed lower levels of IL-4, IL-5 and IL-13, but higher levels of IFN-γ in BALF (all P<0.05). (6) Dexamethasone or SB203580 significantly decreased the hyperemia and edema in airway mucosa, reduced the infiltration of inflammatory cells in the peribronchial areas and alleviated the tracheal epithelium goblet cell metaplasia in asthmatic mice. (7) Treatment with dexamethasone or SB203580 inhibited OVA-induced phosphorylation of p38 MAPK in asthmatic mice as revealed by immunohistochemical staining (both P<0.05). No significant difference in the expression of p38 MAPK was observed among the four groups (all P>0.05). (8) Expression of p-p38 MAPK at protein level in both dexamethasone and SB203580 groups was lower than that in asthma group (both P<0.05).@*Conclusion@#SB203580 regulated the Th1/Th2 balance through inhibiting the activation of p38 MAPK signaling pathway to alleviate OVA-induced airway inflammation.
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Objective: To investigate the dental anatomy of C57BL/6 mice strain. Methods: The skulls and alveolar bones of 16 C57BL/6 mice were scanned by a micro-CT scanner. After 3D reconstruction,the internal and external anatomy of each tooth type was examined. Results: The upper incisors were more curved (mean radius: 2. 37 mm vs. 6. 31 mm) and shorter (mean tooth length: 8. 63 mm vs. 11. 19 mm) than the lower incisors. The palatal roots of the upper 2nd molars (3-rooted),the mesial roots of the lower first molars(double-rooted) and the mesial and distal roots of the lower 2nd molars (double-rooted) had type 1-2 canal form,and all the other roots had a single canal. The mesiodistal diameter of the crown,as well as the numbers of the cusps and developing grooves decreased from the 1st to the 3rd molars. The external tooth shape was very similar as the morphology of the pulp cavity. Conclusion: The C57BL/6 mouse have strong incisors. The tooth size and the anatomic complexity decrease from the 1st to the 3rd molars,which reflects a trend of degradation.
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Objective To investigate the expression of Gli1 protein in colorectal cancer (CRC) tissues,and evaluate its association with the prognoses of the patients.Methods A total of 106 patients were enrolled and their clinicopathological characteristics were analyzed.The expression of Gli1 proteins were detected by immunohistochemical staining,and its association with time to recurrence/metastasis (TTR) and overall survival (OS) of the patients were analyzed.Results The positive rate and expression intensity of Gli1 protein in recurrent or metastatic tumor tissues were higher than those in non-recurrent and non-metastatic tumor tissues [86.84 ％ (33/38) vs.58.82 ％ (40/68),1.32 scores vs.0.71 scores,both P ＜ 0.01),while the positive rate and expression intensity of Ki-67 protein remained no difference between both groups [97.37 ％ (37/38) vs.91.18 ％ (62/68),1.89 scores vs.1.75 scores,both P ＞ 0.05).The positive rates and expression intensities of Gli1 and Ki-67 proteins in CRC tissues were higher than those in adjacent tissues [26.42 ％ (28/106) and 0.27 scores;4.72 ％(5/106),0.05 scores] and normal tissues [3.33 ％ (1/106),0.03 scores;0,0.00 scores] (all P ＜ 0.01).Results of univariate analysis showed that the expression of Gli1 protein,tumor grade and lymph node involvement were significantly associated with TTR,but all of the clinicopathological factors had no obvious association with OS.The association remained significant between the expression of Gli1 protein and TTR in multivariate analysis (P ＜ 0.01).Conclusion The expression of Gli1 protein is an independent prognostic marker of recurrence or metastasis in CRC patients,its high expression implicates a high risk of CRC recurrence or metastasis.
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Objective:To analyze the wall thickness of C-shaped canals in permanent mandibular second molars.Methods:40 ex-tracted permanent mandibular second molars with C-shaped root were collected from native Chinese and were scanned by micro-CT scan-ner.The specimens were reconstructed three-dimensionally by software Mimics 10.01.The roots were sliced from cemento-enamel junc-tion (CEJ)to apex with 1 mm intervals.The cross-sectional root canal configurations were classified into 5 types according to the Fan's Classification.The minimum buccal wall thickness (MBWT),minimum lingual wall thickness(MLWT)and their locations,as well as the wall thickness at the mesial and distal reference sites were detected.Two-way ANOVA and post hoc LSD-t tests were used to com-pare the mean thickness at 4 sides.Results:Among 370 cross-sections of 40 C-shaped roots,C1,C2 and C3 canals were observed on 126(34.1%),46 (12.4%)and 160 (43.2%)sections respectively.Except at the 10 mm level,the mean MLWT was always lower than MBWT;and the MLWT and MBWT were always lower than the wall thickness at the mesial and distal reference sites.The differ-ence was statistically significant (P <0.05)along the root length above the 12 mm level.The MBWT of the C2 and C3 canals was more likely located at the mesial region,and the MBWT of the C1 and the MLWT of C1,C2 and C3 was more frequently located at the center region.Conclusion:The lingual wall of C-shaped canal in mandibualr second molars was the thinnest zone among four sides,and care should be taken during root canal instrumentation and post space preparation to avoid perforation.
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Objective:To study the mathematical relation between the measurements of root canal curvature obtained by Schneider's method(?_S) and Weine's method(?_W).Methods:The axis of a curved root canal was simplified by an arc (whose radius was r and central angle ?) and 2 tangent line segments (whose lengths were l_1 and l_2),the relation of ?_S and ?_W was studied with the help of mathematical analysis according to the different ways of determining the measured angles on the simplified axis.The graphs of the function were analysed.Results:The following formulas were proved:(1)tan?_S=(1-cos?_W+ ksin?_W)/(sin?_W+kcos?_W),k=l_2/r;(2)?_W/2≦?_S≦?_W.If ?_W was in the interval [0,?],a proximate linear correlation existed between ?_S and ?_W.Conclusion:There is a complex function between the 2 angles(?_S and ?_W) measured by Schneider's method and Weine's method,the ratio of the length of the apical straight part to the radius of the canal curvature is an important factor determining the different values of ?_S and ?_W.