Translated clinically, this suggests that patients suffering from autoimmune diseases may develop steroid resistance due to persistent CORT exposure; in the absence of careful control over steroid resistance measures,

Sunitinib nmr patients may thereby enter a vicious cycle where they become dependent on increasing doses of steroids. Eight-week-old C57BL/6 mice were purchased from Harlan (Jerusalem, Israel) and were allowed to acclimatize to our animal facility for 7 days prior to the experimental period. All mice were housed under standard environmental conditions (12:12 light:dark cycle with light onset at 7:00 a.m.) and were allowed free access to food and water throughout the experimental period. Surgical and experimental procedures were approved by the Institutional Animal Care check details and Use Committee (IACUC) of Ben-Gurion University of the Negev, Israel. To detect intracellular FoxP3 we used C57BL/6 transgenic mice expressing enhanced green florescent protein under the control of the mouse FoxP3 promoter. The mice were kindly provided by Dr. Eli Lewis. Mice were randomly assigned into two groups: (i) a group of isolated mice exposed to CVS for 24 days as described below, (ii) and a group of nonstressed mice, kept in groups of 4–8 mice per cage and manipulated only once a week for urine collection and body weight measurement. Following the 24-day experimental period,

mice in the stressed and nonstressed groups were further divided into three groups: (i) mice subjected to behavioral tests, after which they were killed for immunological analysis; (ii) mice injected with MOG35-55 emulsified Interleukin-3 receptor in CFA to induce EAE as described below; and (iii) mice injected with the CORT antagonist mifepristone (Sigma, Israel) daily, 2 hours before exposure to the stressful conditions, throughout the stress period. Mifepristone was dissolved in 100% ethanol and diluted to 5% ethanol in corn oil to a final concentration of 3 mg/mL. A daily dose of 30 mg/kg was injected subcutaneously. Chronic unpredictable stress paradigms typically

follow a schedule of repeated exposure to several randomly assigned stressors a day. The CVS procedure was developed based on several paradigms previously validated as stress inducers in rodents. These included isolation [55]; exposure to cat urine [56]; restraint (placing the mouse in a well-ventilated 50 mL polypropylene tube, 2.8 cm in diameter and 11.5 cm in length) [57]; swimming in cold (4°C) water [58]; illumination during the dark phase, and tilting the home cage at a 45o inclination for 24 hours [30]. Stressor types and stress durations throughout the experiment are provided in Table 1. Stressed and nonstressed mice were tested to evaluate anxiety-like behaviors 24 hours after termination of the experimental protocol (i.e. on day 25) using the following behavioral tests.