Effects of novel bioactive glasses on promoting remineralization of artificial dentin caries / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effects of novel bioactive glasses (BG) including PSC with high phosphorus component and FBG with fluorine-doped element on promoting remineralization of artificial dentin caries.@*METHODS@#(1) BGs were used in this study as follows: PSC (10.8%P2O5-54.2%SiO2-35.0%CaO, mol.%) were synthesized using phytic acid as the phosphorus precursor through sol-gel method. FBG (6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2, mol.%) and 45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O, mol.%) were synthesized by traditional melt method. (2) The above BGs were soaked in simulated body fluid (SBF) for 24 hours. Then X-ray diffraction (XRD) was used to analyze the formation of hydroxyapatite (HA) crystals. (3) Prepared 1 mm thick dentin slices were soaked in 17% ethylene diamine tetraacetic acid (EDTA) for 1 week to demineralize the dentin. Then the dentin slices treated by BG were soaked in SBF for 1 week. Field emission scanning electron micro-scopy (FE-SEM) was used to observe the surface morphology of the dentin slices. (4) Four cavities were prepared to 1 mm depth in each 2 mm thick dentin slice, then were treated with lactic acid for 2 weeks to form the artificial dentin caries. Wax, mineral trioxide aggregate (MTA), PSC and FBG were used to fill four cavities as blank control group, MTA group, PSC group and FBG group respectively. Then the spe-cimens were soaked in SBF for 4 weeks. The changes of depth and density of demineralized dentin were analyzed using Micro-CT before filling and after 2 and 4 weeks filling.@*RESULTS@#(1) PSC and FBG promoted mineral formation on the surfaces of the demineralized dentin. And the speed was faster and crystallinity was higher in PSC group than the FBG and 45S5 groups. (2) The increased mineral density of artificial dentin caries in PSC group were (185.98 ± 55.66) mg/cm3 and (213.64 ± 36.01) mg/cm3 2 and 4 weeks after filling respectively, which were significantly higher than the control group [(20.38 ± 7.55) mg/cm3, P=0.006; (36.46 ± 10.79) mg/cm3, P=0.001]. At meanwhile, PSC group was also higher than MTA group [(57.29 ± 10.09) mg/cm3; (111.02 ± 22.06) mg/cm3], and it had statistical difference (P=0.015; P=0.006). The depth of remineralized dentin in PSC group were (40.0 ± 16.9) μm and (54.5 ± 17.8) μm 2 and 4 weeks respectively, which were also statistically different from the control group (P =0.010;P=0.001). There were no statistical differences between the control group and MTA group. The above effects of FBG group were between PSC and MTA.@*CONCLUSION@#PSC has advantages in the speed, quality and depth of mineral deposition in the demineralized layer of artificial dentin caries. It would be expected to be an ideal material to promote the remineralization of dentin caries.

Efecto de las nanopartículas industriales TiO 2 , SiO 2 y ZnO sobre la viabilidad celular y expresión génica en médula ósea roja de mus musculus / Effect of the Industrial Nanoparticles TiO 2 , SiO 2 and ZnO on Cell Viability and Gene Expression in Red Bone Marrow of Mus Musculus

RESUMEN Objetivos Evaluar el efecto de las nanopartículas de ZnO, TiO2 y SiO2 sobre la viabilidad celular y la expresión génica de las interleuquinas 7 y 3 y del factor estimulante de colonias de granulocito - macrófago (GM-CSF) en Mus musculus. Materiales y métodos Se extrajo médula ósea roja de cinco roedores (Balb/c) para el estudio de viabilidad celular mediante la prueba de MTT. Por otro lado, grupos cinco roedores fueron inoculados vía intraperitoneal con dosis de 0,5; 1; 2,5; 5 y 10 mg/kg de nanopartículas de ZnO y SiO2 y de 5; 10; 15; 20 y 25 mg/kg de nanopartículas de TiO2, 30 h después, se obtuvo el ARN a partir de la médula ósea roja para los análisis de expresión génica empleando las técnicas de PCR y RT-PCR cuantitativa. Resultados Las nanopartículas de ZnO y SiO2 redujeron la viabilidad celular de una manera dosis-dependiente en un 37 y 26%, respectivamente, a partir de una dosis de 1 mg/kg. En cuanto al efecto sobre la expresión génica, a las dosis 5 y 10 mg/kg, las nanopartículas de TiO2 redujeron en mayor porcentaje la expresión de las interleuquinas 7 y 3 (55,3 y 70,2% respectivamente), con respecto a la expresión del GM-CSF, el mayor porcentaje de reducción lo produjo las nanopartículas de SiO2 (91%). Las nanopartículas de ZnO redujeron a partir de las dosis de 20 y 25 mg/kg. Conclusiones Las nanopartículas de ZnO, SiO2 y TiO2 alteran la viabilidad celular y la expresión génica en la médula ósea de ratón.

ABSTRACT Objectives To evaluate the effect of ZnO, TiO2 and SiO2 nanoparticles on cell viability and expression of the interleukin 7, interleukin 3, and granulocyte-macrophage colony stimulating factor (GM-CSF) genes in Mus musculus. Material and methods Red bone marrow was extracted from five Balb/c mice for the analysis of cell viability using the MTT test. The mice were divided into two groups of five each: one group was inoculated intraperitoneally with 0.5, 1.0, 2.5, 5.0, and 10 mg/kg of ZnO and SiO2 nanoparticles, respectively, and the other group was inoculated with 5.0, 10.0, 15.0, 20.0, and 25 mg/kg of TiO2 nanoparticles, respectively. Thirty hours later, RNA was extracted from the red bone marrow of the mice in both groups for gene expression analysis using quantitative PCR and RT-PCR. Results ZnO and SiO2 nanoparticles reduced cell viability in a dose-dependent manner by 37% and 26%, respectively, starting at a dose of 1 mg/kg. TiO2 nanoparticles at 5 mg/kg and 10 mg/kg reduced the gene expression of interleukins 7 and 3 by 55.3% and 70.2%, respectively, and SiO2 nanoparticles caused the greatest decrease (91%) in the expression of GM-CSF. ZnO nanoparticles reduced the expression of GM-CSF starting at doses of 20 mg/kg and 25 mg/kg. Conclusions ZnO, SiO2 and TiO2 nanoparticles affect cell viability and gene expression in the mouse bone marrow.

Biocompatibility and osteogenesis of the castor bean polymer doped with silica (SiO2) or barium titanate (BaTiO3) nanoparticles

PURPOSE: To evaluate the biocompatibility and osteogenesis of castor oil polymer doped with SiO2 or BaTiO3 nanoparticles. METHODS: Twenty four male rats Wistar were submitted to bone defect filled with castor oil polymer. The animals were distributed in two experimental groups had been formed with 12 animals each: Group 1 - Castor oil polymer doped with 0.30 grams of SiO2 replacing 0.30 grams of CaCO3. Group 2 - Castor oil polymer doped with 0.30 grams of BaTiO3 replacing 0.30 grams of CaCO3. Euthanasia occurred 30 and 60 days after surgery and the femurs were sent to histological analysis and MEV. RESULTS: The implants were biocompatible and allowed for progressive osteogenesis through osteoconduction in both observation periods. There was significant bone neoformation at 30 and 60 days in both groups within the histomorphometric evaluation, but group 1's osteogenesis was lesser in the 30 and 60-day periods observed when compared to the animals of group 2. The MEV morphometric evaluation evidenced a lesser percentage of osseous tissue filling within the BaTiO2-doped polymer. CONCLUSION: The castor oil polymer doped with SiO2 or BaTiO3 remained biocompatible and allowed for progressive osteogenesis in both observation periods. .

Effect of silica treatment on histopathology of intestinal & hepatic amoebiasis in murine model.

Histopathological changes in intestinal and hepatic amoebiasis were studied in Swiss albine mice with and without silica pretreatment. The intestinal infection rate was higher in silica treated mice (83%) as compared to non-silica treated mice (33%). Histologically all the silica treated mice had caecal ulceration which tended to spread across the muscularis propria into the serosal layer. The hepatic lesions were observed grossly in 100 and 60 per cent mice with and without silica treatment, respectively. However, the liver lesions in the silica treated mice were more severe, leading to satellite abscesses and in some cases the capsule ruptured leading to adhesions to the diaphragm and peritoneum. Histologically, the blockade of histiocytes with silica resulted in mainly a neutrophilic damage which was extensive and widespread. It also destroyed the amoeba and led to abundant fibrosis. In the non-silica group the damage was slow and devoid of neutrophils with quicker healing and lack of fibrosis resembling human hepatic lesions.