[ 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.

Objective To investigate the effects of chronic treatment with levamisole (LMS) on imidazoline I2 receptor (I2R) in rats with experimental autoimmune encephalomyelitis (EAE).Methods Thirty female Wistar rats were randomly divided into three groups:control group (n=8),EAE model group (n=10),EAE+LMS treatment group (n=12); the rat models of EAE were induced by immunizing with guinea pigs spinal cord homogenate.Subcutaneous injection of 0.5 mL of normal saline+complete Freund's adjuvant (CFA) emulsion was performed to rats in the control group,and 0 and 24 h after the that,intraperitoneal injection of 0.4 mL of saline twice daily was performed; subcutaneous injection of 0.5 mL of homogenate+CFA emulsion was performed to rats in the EAE model group; subcutaneous injection of 0.5 mL of homogenate+CFA emulsion was performed to rats in the EAE+LMS treatment group,and 0 and 24 hafter the that,intraperitoneal injection of LMS (10 mg/kg) twice daily was performed.The severity of EAE was scored according to the signs and symptoms.Pathological changes were observed through hematoxylin-eosin staining and Luxol-Fast blue dyeing,and the degrees of inflammatory infiltration were evaluated.The maximal binding capacity (Bmax) and dissociation content (Kd) of I2R were measured by radioligand binding assay.Results As compared with rats in the EAE model group,rats in the EAE+LMS treatment group had lower incidence of EAE,alleviated clinical symptoms,prolonged latency and decreased central nervous system inflammation.Radioligand binding assay showed that both the Bmax values and Kd constant of I2R (266.1 ±28.13 fmol/mg and 5.307 ± 1.107) in the EAE model group were increased as compared with those in the control group (177.5±26.10 fmol/mg and 3.586±1.053,respectively),with statistically significant differences (P＜0.05).As compared with those in the EAE model group,the I2R Bmax values in the EAE+LMS treatment group (496.1±52.31 fmol/mg) were markedly increased (P＜0.05),but there were no significantly differences in Kd values of I2R between these two groups (P＞0.05).Conclusion Chronic treatment with LMS has beneficial neuroprotective effect on rats with EAE,and its mechanism might be related to the regulation of I2R.