Effects of cyclosporin A and a rapamycin derivative (SAR943) on chronic allergic inflammation in sensitized rats

Summary Immunomodulators such as cyclosporin A (CsA) and SAR943 (32‐deoxorapamycin) inhibit single allergen‐induced allergic inflammation such as eosinophilic and lymphocytic infiltration and mRNA expression for interleukin (IL)‐4 and IL‐5. We examined the effects of CsA and SAR943, administered orally, on asthmatic responses in a rat model of chronic allergic inflammation. Sensitized Brown‐Norway (BN) rats were exposed to ovalbumin (OVA) aerosol every third day on six occasions. CsA (5 mg/kg/day), SAR943 (2·5 mg/kg/day) or vehicle (Neoral™) was administered orally, once a day, from days 10 to 21 (a total of 12 doses). We measured eosinophilic and T‐cell inflammation in the airways, proliferation of airway cells by incorporation of bromodeoxyuridine (BrdU) and bronchial responsiveness to acetylcholine. CsA had no effects, while SAR943 inhibited airway smooth muscle (ASM, P