RESUMO
Postmenopausal osteoporosis (PMO) is the most common metabolic bone disease in women after menopausal. Recent works focused on cross—talk between immune regulation and bone metabolism pathways and suggested Treg cells suppressed bone resorption and osteoclasts (OC) differentiation in bone marrow via cell—cell contact interaction and/or secreting of IL—10 and TGF—beta. In this study, we investigated the impact of estrogen on regulatory T cells (Treg cells) trafficking and staying in bone marrow and we found that a significant reduction of Treg cell population in bone marrow in estrogen deficiency ovariectomied (OVX) mice. We then studied the expressions of chemokines CXCL12/CXCR4 axes, which were critical to Treg cells migration and our data show the expression of CXCR4 on Treg cells was relative with oestrogen in vivo, however, the expression of CXCL12 was not. Furthermore, the loss of trafficking ability of Treg cells in OVX mice was recoverable in our system. These findings may mechanistically explain why Treg cells lose their suppressive functions on the regulation of OC cells and demonstrate a previously unappreciated role for estrogen, which may be critical to the novel therapy in clinical practice of PMO patients.
Assuntos
Quimiocina CXCL12/biossíntese , Estrogênios/deficiência , Osteoclastos/citologia , Osteoporose Pós-Menopausa/fisiopatologia , Receptores CXCR4/biossíntese , Animais , Medula Óssea/metabolismo , Células da Medula Óssea/imunologia , Reabsorção Óssea/imunologia , Osso e Ossos/metabolismo , Diferenciação Celular , Células Cultivadas , Regulação para Baixo , Estrogênios/metabolismo , Humanos , Interleucina-10/metabolismo , Camundongos , Ovariectomia , Linfócitos T Reguladores/imunologia , Fator de Crescimento Transformador beta/metabolismoRESUMO
Physical and chemical characteristics of spiramycin (SPM) were reviewed in this paper. The degradation rule and kinetics of SPM in acid and alkaline solutions were studied, and the kinetic parameters were calculated. The experimental results showed that the stable range of SPM in water is at pH 4.0~10.0 Degradation occurred seriously at pH<4.0 and pH> 10.0, especially at pH< 2.8 and pH> 12.8. For this reason, the yield of SPM is greatly affected. The solubility in water was also studied by using reference data. The thermodynamical parameters were calculated. The results showed that the solution of SPM in water is exothermic. The solubility decreases as temperature rises.
