ABSTRACT
Sabe-se que o flúor causa alterações químicas e celulares no osso, dependendo da dosagem e do tempo de exposição a esse elemento. Já foi demonstrado que alterações clínicas importantes, como a osteoporose, osteopetrose e esclerose óssea, podem ser geradas pela ingestão de flúor. Sabe-se que o flúor pode guiar os osteoblastos ao crescimento, sob doses e tempos de exposição específicos. A sensibilidade dos tecidos mineralizados ao fluoreto responde a mecanismos genéticos inerentes a cada população. Dentro de uma mesma espécie, diferentes linhagens apresentam um comportamento distinto frente a esse fármaco. Durante várias décadas, os estudos com fluoretos resumiram-se ao fluoreto de sódio, amplamente utilizado na prevenção das cáries dentárias. Recentemente, outras fontes de fluoretos como TiF4 e SnF2 têm sido buscadas, com intuito de potencializar as vantagens desse elemento. Porém não existem estudos ainda sobre o efeito do AlF3 sobre o tecido ósseo até a presente data. Desse modo, achamos oportuno investigar seu papel, quando administrado a células ósseas e para tal, investigamos a viabilidade e padrão de atividade das fosfatases desse sal (AlF3) quando administrado às células da linhagem pré-osteblástica MC3T3, em comparação ao NaF. Além disso, sabendo que diferentes células apresentam comportamento distinto ao tratamento com fluoretos, estudamos o papel do NaF quando administrado a duas linhagens celulares de camundongos com densidades ósseas distintas e com diferentes susceptibilidades ao fluoreto: C3H/HeJ e C57BL/6J (C3H e C57, alta e baixa densidades ósseas, respectivamente). As células também foram avaliadas quanto à viabilidade celular e ao perfil das fosfatases. Todos os resultados foram submetidos à Análise de Variância a três critérios e nos permitiu identificar que entre os sais de fluoreto, apenas o NaF promoveu alterações na viabilidade celular das células MC3T3. O AlF3 não exerceu influência na atividade da fosfatase alcalina...
It is well known that fluoride causes chemical and cellular alteration on bone tissue, depending on the dosage and time of exposure to this element. Several studies have been conducted to show that some bone diseases, such as osteoporosis, osteopetrosis and esclerosis, can occur as a consequence of the excessive fluoride uptake. Fluoride can lead osteoblast to proliferate, under certain conditions as time and dosage. The same way, excessive dosages of fluoride can alter protein activity in osteoblasts, by changing the expression of retated genes. Sensitivity of mineralized tissues to fluoride depends on a genetic background inherent to each population. Within the same specie, different lineages present distint behavior to the ingestion of this íon. Over several decades, many researches focused on the study of NaF as the only source of fluoride, once it is wide spread used to the prevention of dental caries. More recently, different sources of fluoride have been assessed, like TiF4 e SnF23 did not exibit influence over on alkaline phosphatase when pre-osteoblast cells are considered, but the effect of this fluoride salt on the activity of total and tartarate resistant acid phosphatases ocurrs on a dicotomic way. When we consider a mixed cell population, collected from calvária as for the C3H and C57 assays, NaF did interfered as with the proliferation rate as phosphatase activities on a very distinct fashion between the two lineages. Thus, it is possible to conclude that NaF is able to exert variable effects in different cell types and enzyme activities; on the other hand, AlF3 effects are more specific and surrounded in pre-osteblastic cells.
Subject(s)
Animals , Mice , Bone Density , Fluorine/toxicity , Osteoblasts , Fluorine/metabolism , Cell Line , Osteoblasts/cytology , Cell Survival , Time FactorsABSTRACT
Sabe-se que o flúor causa alterações químicas e celulares no osso, dependendo da dosagem e do tempo de exposição a esse elemento. Já foi demonstrado que alterações clínicas importantes, como a osteoporose, osteopetrose e esclerose óssea, podem ser geradas pela ingestão de flúor. Sabe-se que o flúor pode guiar os osteoblastos ao crescimento, sob doses e tempos de exposição específicos. A sensibilidade dos tecidos mineralizados ao fluoreto responde a mecanismos genéticos inerentes a cada população. Dentro de uma mesma espécie, diferentes linhagens apresentam um comportamento distinto frente a esse fármaco. Durante várias décadas, os estudos com fluoretos resumiram-se ao fluoreto de sódio, amplamente utilizado na prevenção das cáries dentárias. Recentemente, outras fontes de fluoretos como TiF4 e SnF2 têm sido buscadas, com intuito de potencializar as vantagens desse elemento. Porém não existem estudos ainda sobre o efeito do AlF3 sobre o tecido ósseo até a presente data. Desse modo, achamos oportuno investigar seu papel, quando administrado a células ósseas e para tal, investigamos a viabilidade e padrão de atividade das fosfatases desse sal (AlF3) quando administrado às células da linhagem pré-osteblástica MC3T3, em comparação ao NaF. Além disso, sabendo que diferentes células apresentam comportamento distinto ao tratamento com fluoretos, estudamos o papel do NaF quando administrado a duas linhagens celulares de camundongos com densidades ósseas distintas e com diferentes susceptibilidades ao fluoreto: C3H/HeJ e C57BL/6J (C3H e C57, alta e baixa densidades ósseas, respectivamente). As células também foram avaliadas quanto à viabilidade celular e ao perfil das fosfatases. Todos os resultados foram submetidos à Análise de Variância a três critérios e nos permitiu identificar que entre os sais de fluoreto, apenas o NaF promoveu alterações na viabilidade celular das células MC3T3. O AlF3 não exerceu influência na atividade da fosfatase alcalina...
It is well known that fluoride causes chemical and cellular alteration on bone tissue, depending on the dosage and time of exposure to this element. Several studies have been conducted to show that some bone diseases, such as osteoporosis, osteopetrosis and esclerosis, can occur as a consequence of the excessive fluoride uptake. Fluoride can lead osteoblast to proliferate, under certain conditions as time and dosage. The same way, excessive dosages of fluoride can alter protein activity in osteoblasts, by changing the expression of retated genes. Sensitivity of mineralized tissues to fluoride depends on a genetic background inherent to each population. Within the same specie, different lineages present distint behavior to the ingestion of this íon. Over several decades, many researches focused on the study of NaF as the only source of fluoride, once it is wide spread used to the prevention of dental caries. More recently, different sources of fluoride have been assessed, like TiF4 e SnF23 did not exibit influence over on alkaline phosphatase when pre-osteoblast cells are considered, but the effect of this fluoride salt on the activity of total and tartarate resistant acid phosphatases ocurrs on a dicotomic way. When we consider a mixed cell population, collected from calvária as for the C3H and C57 assays, NaF did interfered as with the proliferation rate as phosphatase activities on a very distinct fashion between the two lineages. Thus, it is possible to conclude that NaF is able to exert variable effects in different cell types and enzyme activities; on the other hand, AlF3 effects are more specific and surrounded in pre-osteblastic cells.
Subject(s)
Animals , Mice , Bone Density , Fluorine/toxicity , Osteoblasts , Fluorine/metabolism , Cell Line , Osteoblasts/cytology , Cell Survival , Time FactorsABSTRACT
To study the contribution of T cell subsets in the pathogenesis of Murine hepatitis virus Type3 (MHV-3) induced chronic viral hepatitis in C3H/Hej mice, ninety C3H/Hej mice were chosen to individually receive 10 plaque forming units (PFU) of MHV-3 intraperitoneally. The changes of virus titer and pathology in liver tissue were examined by standard plaque assay and by the hematoxylin/eosin (HE) staining method from 2 days post MHV-3 infection. The ratios of T cell subsets including CD3+CD4+CD8-, CD3+CD4-CD8+, CD3+CD4-CD8-, CD3+CD4+CD25+, CD3+CD4+CD25- and CD3+CD4-CD25+ T lymphocyte of total T lymphocytes in blood, spleen and liver were examined at 0, 2, 4, 6,8, 10, 12, 15, 20, 25, 30, 40 days post MHV-3 infection by flow cytosorting. We observed that the virus titer raised and showed persistent virus duplications and inflammatory changes in the livers of C3H/Hej mice from 2 days post MHV-3 infection. The double negative T cell (DN Treg cell) and CD4+CD25+ T cell ratios increased significantly from 2 days post MHV-3 infection in C3H/Hej mice, and CD3+CD4+CD8-, CD3+CD4-CD8+, CD3+CD4+CD25- and CD3+CD4-CD25+ T cell ratios decreased accordingly. In conclusion, the changes of virus titer and pathology in the livers of C3H/Hej mice post MHV-3 suggest their contribution to viral persistence. Further characterizations of DN Treg cells are that infection indicates that MHV-3 could induce the chronic inflammation in livers of C3H/Hej mice.The increase of the DN Treg cell and CD4+CD25+ T cell ratios in C3H/Hej mice post MHV-3 infection suggests that DN Treg cells and CD4+CD25+ T cells may both have important suppressive immunomodulation functions in the development of chronic viral hepatitis and have important roles in the virus persistent infection. Further characterizations of DNT cell and CD4+CD25+ T cell are under investigation.
ABSTRACT
To determine whether lipopolysaccharide (LPS)-induced prostaglandin (PG) E2 production is responsible for reduced spontaneous physical activity, we measured LPS ( 1 mg/kg, i. v.)-induced changes in voluntary wheel-running activity for 24 hours in both C3H/HeJ (LPS unresponsive due to a mutation in the <i>tlr4</i> gene) and C3H/HeN (LPS response) mice. We also examined the effect of <i>tlr4</i>-gene mutation on LPS-induced PGE2 production using peritoneal macrophages from the C3H/HeJ and C3H/HeN mice. In addition, the voluntary wheel-running activity of the C3H/HeN mice, which were injected with the PGE2 inhibitor indomethacin (IM ; 0-20 mg/kg, i. p.) 30 min before injection with or without LPS ( 1 mg/kg), was monitored for 24 hours. Wheel-running activity in the C3H/HeJ mice was maintained in spite of LPS injection, but the activity in the C3H/HeN mice was significantly reduced by LPS injection. <i>In vitro</i> experiment showed peritoneal macrophage PGE2 production to be lower in the C3H/HeJ mice than that in the C3H/HeN mice. IM partially, but significantly, attenuated the LPS-induced reduction in wheel-running activity in the C3H/HeN mice. Our results suggest that the transient reduction in physical activity after LPS injection is partially mediated by LPS-induced PGE2 production, and that other factors also play a role.
ABSTRACT
BACKGROUND AND OBJECTIVE: Murine system for studying allergic diseases has been popular in the fields of food allergy and development of their therapeutic strategies. However, there has been no information about the age-dependent changes of natural immune responses of naive C3H/HeJ mice. The purpose of this study was to evaluate the age-dependent changes of B and T-cell mediated immunologic parameters in naive C3H/HeJ mice, which can provide information for experimental planning and analysis of research results. SUBJECTS AND METHODS: Eight naive, female, 5-week-old C3H/HeJ mice were grown under the regular mouse chow feeding conditions for 6 weeks. Sera were obtained at week (w) 5, w6, w8 and w10 for measuring total and chow-specific IgE, IgG1 and IgG2a antibodies. Splenocyte proliferation (at w8 and w10) and cytokine production (at w6, w8 and w10) were evaluated with or without Con A stimulation with pooled splenocytes from two mice of each age group. Serum antibodies and cytokines (IL-4, IL-5, IL-12, INF-gamma, TGF-beta1) were measured by ELISA. Using RT-PCR, IL-4 and INF-gamma mRNA expressions were measured in Peyer's patch and spleen tissue at w10. RESULTS: The levels of total IgE and IgG1 were increased by age while the level of IgG2a was decreased. Chow-specific IgE and IgG2a responses were neglectable through out the whole experimental period (20-30 ng/ml or less). Chow-specific IgG1 levels were measured in the significant concentrations (200-300 ng/ml) but there was no age-dependent change through out the experiment. Con A stimulated-splenocyte proliferation indexes were variable according to the culture-durations and ages of mice. The higher proliferation indexes were observed in the wells receiving thymidine pulse at 48-hour culture, especially in the mice at w10. Con A stimulated IL-4 production in the 72-hour splenocyte culture supernatant was significantly increased at w8, and w10 while INF-gamma production increased only at w10. The changes in the production of IL-5, IL-12 and TGF-beta did not provide significant information in the present study. The ratio of IL-4/IFN-gamma mRNA expression was higher in Peyer's patch than in the spleen. CONCLUSION: The changes of B-cell and T-cell mediated immunologic parameters were complex and variable according to the age in naive C3H/HeJ mice under regular chow feeding conditions. For that reason, the information from the present study needs to be considered in the course of planning or analysing research/data using murine systems.