RESUMO
Objective To investigate the effect of doxycycline on the Th1/Th2 cell balance in experimental allergic encepha-lomyelitis(EAE)rats.Methods Forty female Wistar rats were randomly divided into the EAE control group,low,medium and high does DOX treatment groups,10 cases in each group.The onset situation in rats was observed.The IL-4 and IFN-γlevels secreted by peripheral blood mononuclear cells (PBMC)at the peak stage were detected.The levels of IL-1β,IL-10,TNF-αin brain tissue,and the albumin content in cerebrospinal fluid and serum were detected.The QA value was calculated.Results In each DOX group,the clinical symptoms of rats were alleviated compared with the EAE control group.In each DOX group,the PBMC secreting IFN-γlev-el and IFN-γ/IL-4 ratio in the onset peak stage were lower than those in the EAE control group,while the IL-4 level was higher than that in the EAE control group(P 0.05),but the difference between other DOX groups had statistical significance(P <0.01).The IL-1βand TNF-αlevels of brain tissue and QA value during onset peak stage in various doses DOX groups were decreased compared with the EAE control group,while the IL-10 level was increased compared with the EAE control group(P <0.05).With the DOX dose increasing,the levels of IL-1β,TNF-αand QA value in various doses DOX groups became lower,the IL-10 level became high-er,there was statistically significant difference among various doses DOX groups (P <0.05 ).Conclusion DOX can obviously alle-viate the clinical symptoms of EAE rats,its mechanism may be related with that DOX could decrease the level of Th1 cytokine and increase the level of Th2 cytokine,correct the Th1/Th2 cell balance,thus protect the blood brain barrier(BBB).
RESUMO
In order to improve the interfacial bonding strength of hydroxyapatite/polyurethane implanted material and dispersion of hydroxyapatite in the polyurethane matrix, we in the present study synthesized nano-hydroxyapatite/polyurethane composites by in situ polymerization. We then characterized and analyzed the fracture morphology, thermal stability, glass transition temperature and mechanical properties. We seeded MG63 cells on composites to evaluate the cytocompatibility of the composites. In situ polymerization could improve the interfacial bonding strength, ameliorate dispersion of hydroxyapatite in the properties of the composites. After adding 20 wt% hydroxyapatite into the polyurethane, the thermal stability was improved and the glass transition temperatures were increased. The tensile strength and maximum elongation were 6.83 MPa and 861.17%, respectively. Compared with those of pure polyurethane the tensile strength and maximum elongation increased by 236.45% and 143.30%, respectively. The composites were helpful for cell adhesion and proliferation in cultivation.