ABSTRACT
[ ABSTRACT ] AIM: To study the effect of idazoxan on the permeability of inflammatory blood-brain barrier ( BBB) model in vitro and the expression of tight junction protein ZO-1.METHODS:In vitro BBB model was established by murine brain endothelial cell line bEnd.3 incubated for 7 d.The cells were treated with TNF-α(10 nmol/L) for addi-tional 24 h to establish the inflammatory BBB model, which was pretreated with IDA at doses of 50, 100 and 200μmol/L, respectively.The permeability was measured using fluorescein isothiocyanate-conjugated dextran (FD-40, MW 40,000), the expression of ZO-1 was detected by Western blot analysis, the distribution of ZO-1 was observed by immunofluores-cence, and the mRNA expression of MMP-9/TIMP-1 was measured by RT-PCR.RESULTS:After incubated for 7 d, b. End3 cells converged to be confluent monolayer with low permeability.The inflammatory BBB model induced by TNF-αtreatment displayed much higher permeability with decreased expression of tight junction protein ZO-1, destroyed distribu-tion of ZO-1 and increased mRNA expression of MMP-9.When pretreated with IDA, the permeability was greatly de-creased, the expression of ZO-1 was greatly increased, the abnormal distribution of ZO-1 was greatly ameliorated and the mRNA expression of MMP-9 was obviously reduced.The effect was most significant in IDA ( 200 μmol/L )-pretreated group (P<0.01).CONCLUSION:IDA directly acts on brain endothelial cells to reduce the expression of MMP-9, in-crease the expression of tight junction protein ZO-1 and ameliorate the destroyed distribution of ZO-1 in the inflammatory BBB, thus reversing the abnormally elevated permeability in a inflammatory BBB model in vitro induced by TNF-α.
ABSTRACT
The core-crosslinked polymeric micelles were used as a new drug delivery system, which can decrease the premature drug release in blood circulation, improve the stability of the micelles, and effectively transport the drug into the therapy sites. Then the drug bioavailability increased further, while the side effect reduced. Most drugs were physically entrapped or chemically covalent with the polymer in the internals of micelles. Based on the various constitutions and properties of polymeric micelles as well as the special characteristics of body microenvironment, the environment-responsive or active targeting core-crosslinked micelles were designed and prepared. As a result, the drug controlled release behavior was obtained. In the present paper, the research progress of all kinds of core-crosslinked micelles which were published in recent years is introduced. Moreover, the characteristic and application prospect of these micelles in drug delivery system are analyzed and summarized.
ABSTRACT
[ ABSTRACT] AIM:To study the effect of idazoxan ( IDA) on the permeability of blood-brain barrier ( BBB) and the expression of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in mouse ex-perimental autoimmune encephalomyelitis (EAE).METHODS: Female C57BL/6 mice (n=36) were randomly divided into control group, EAE group and IDA group, with 12 mice in each group.EAE was induced by myelin oligodendrocyte glycoprotein 35-55 ( MOG35-55 ) .IDA (2 mg/kg, ip, bid) was administered for 15 d after immunization.The neurological defects of the mice were observed daily and scored.The pathological changes were observed under microscope with HE stai-ning and LFB myelin staining.The BBB permeability was detected by Evans blue extravasation.The expression of MMP-9 and TIMP-1 in the brain of EAE mice was determined by Western blotting.RESULTS: Compared with EAE group, the score of neurological defects in IDA group was decreased, the inflammation was relieved, the BBB permeability was re-duced, and the expression MMP-9 and the ratio of MMP-9/TIMP-1 were decreased ( P<0.05 ) .CONCLUSION: The neuroprotective effect of IDA on mouse EAE might be related to the down-regulation of MMP-9 and the ratio of MMP-9/TIMP-1, thus reducing the degradation of BBB and the permeability of BBB, and ameliorating the pathologic process of EAE.
ABSTRACT
Objective To explore the immunomodulatory mechanism of 2-(-2-benzofuranyl )-2-imidazoline(2-BFI) in rat model of experimental autoimmune encephalomyelitis (EAE).Methods Fifty fe-male Sprague-Dawley(SD) rats were randomly divided into five groups by random digit table , including con-trol group(n=10), EAE model group(n=10), low dose 2-BFI group(1.5 mg/kg, n=10), median dose 2-BFI group (3 mg/kg, n=10) and high dose 2-BFI group (6 mg/kg, n=10).The SD rat model of EAE was induced by immunizing with a guinea pigs′spinal cord homogenate ( GPSCH ) .The severity of EAE was scored according to the signs and symptoms .Pathological changes were observed through Hematoxylin-eosin staining, and then the degrees of inflammatory infiltration were evaluated .The number of activated neuroglia that expressed GFAP and iba 1 in lumbar cords was counted by immunohistochemistry .The expressions of IL-1β, IFN-γ, IL-4 and IL-10 in cervical cords were measured by ELISA .Results Compared with EAE group, rats in the low, median and high dose 2-BFI treatment group had lower incidence of EAE , prolonged latency and decreased CNS inflammation , but only the median dose group showed significant alleviation in clinical symptoms and decrease in CNS inflammatory cell infiltration (P<0.05).Immunohistochemical re-sults showed that the numbers of activated microglia were significantly inhibited ,but the numbers of activated astroglia were increased in the rats treated with median dose of 2-BFI in comparison with the EAE group ( P<0.05).Results of ELISA demonstrated that expressions of IL-1βand IFN-γin 3 mg/kg 2-BFI treated group were significantly decreased compared with that in the EAE group (P<0.05), but expressions of IL-4 and IL-10 were remarkably increased(P<0.05).Conclusion 2-BFI at median dose of 3 mg/kg has a benefi-cial neuroprotective effect on rats with EAE , and its mechanism might be related to immunodulation .
ABSTRACT
Objective:To explore effects of Idazoxan(IDA) on changes of neuroglial cells in spinal cords of rats with experimental autoimmune encephalomyelitis(EAE).Methods:Rat EAE was induced by immunization with spinal cord homogenates of Geania pigs.EAE clinical manifestations were assessed in terms of the scoring standards.Histological investigation and immunohistochemistry were observed for the inflammatory dedmylinative lesion of CNS and morphology of glial cells.Results:Ida could not decrease the incidence of EAE,but alleviate its clinical manifestation and histological changes.On day 15 after immunization,astrocytes in and around the inflammatory dedmylinative lesion of CNS in EAE rats treated with Ida increased in number and size,on the contrary,microglia decreased in number and size.Conclusion:Ida has protective effects on EAE and its functional mechanism may be concerned with modulation of immunological mechanism of CNS.