BACKGROUND: The animals commonly used to induce experimental allergic encephalomyelitis (EAE) in oversea laboratory are rodentia animals such as Lewis rats. But in China we are short of Lewis rats. The un-susceptive animal Wistar rats are inexpensive and plentiful. The adding of pertussis toxin may induce EAE successfully in EAE un-susceptive Wistar rats.OBJECTIVE: To investigate the influence of pertussis toxin injected atdifferent sites in inducing EAE model in un-susceptive Wistar rats.DESIGN: A randomized control animal experiment.SETTING: Institute of Brain Science, Shanxi Datong University.MATERIALS: The study was performed in the Institute of Brain Science of Shanxi Datong University from March to October in 2003. Fifty-eight und adjuvant (CFA) group (n=10).METHODS: Besides routine immunization, each rat in the foot dorsum EAE group and intraperitoneal EAE group was administrated with 005 mL pertussis toxin (containing 5.0×1010 thalli), which were given intraperitoneally and subcutaneously on one hind foot respectively, and the antigen in the CFA group was replaced by CFA.cidence rate and tine of atta ck: In the foot dorsum EAE group, the incidence of EAE was 87.5% (21/24), and the time of attack was at (10.25 ±1.67) days after immunization, which were significantly different from those in the intraperitoneal EAE group [35.7% (9/24), (14.8±l.79) days, P sum EAE group, the change of body mass was (-16.00±7.30) g and the symptomscpre was 3.4±0.7, and those in the intraperitoneal EAE group Therewere no or little infiltration of inflammatory cells in the encephalon and spinal cord of CFA rats. In the EAE rats, there were inflammatory cells infiltrated in the boundary of white matter and gray matter of lumbar intumescence, spinal pia mater, spinal parenehyma, and the boundary of cerebral cortex and medulla, even deep medulla, meninges and around lateral ventricle. There were also mild inflammations in the cerebellum,brainstem and optic chiasma, which were concordant with the observed asynchronism, tic, etc. Hematoxylin and eosin (HE) staining displayed that the infiltrated mononuclear cells assembled in perivascular spaces, which were identified by morphological criteria as lymphocyte and macrophages.Forming typical muff-like changes, the inflammation was less severe in intraperitoneal EAE group than in subcutaneous foot dorsum EAE group.CONCLUSION: The EAE model induced in Wistar rats by Pertussis toxin administered subcutaneously on foot dorsum has the representative course of diseases, pathology change and clinical manifestation and the incidence of diseases is high and the cost is low. So it is a more ideal EAE model inducing method.