Abstract
Contradictory data are available on the effect of nicotine and caffeine on the function and structure of the immune system. This study was designed to investigate the effect of the combined administration of nicotine and caffeine on the CD68-positive macrophages in the thymus gland and ilial payer patches of the rat. Twenty four male albino rats are assigned into 4 groups (n=6); the control, nicotine-treated (10 mg/kg/body weight), caffeine-treated (100mg/kg/bodyweight) and combined nicotine- and caffeinetreated groups. After 4 weeks, the thymus gland and ileum were dissected out and processed for immuno histochemical examination using anti-CD68 and anti-caspase-3 antibodies for detection of macrophages and apoptosis, respectively. The number of CD68+ve macrophages as well as the density of CD68 immuno expression significantly decreased in the thymus and ilial payers patches following the single and combined administration of nicotine and caffeine. The number of apoptotic cells significantly increased in the thymus and ilial payers patches of the groups treated with nicotine, caffeine and the combination of them compared to the control. The combined administration of nicotine and caffeine significantly increased CD68+ve macrophages and significantly reduced apoptosis compared to the group received nicotine alone. This ameliorative effect of caffeine might be attributed to its antioxidant and anti-inflammatory potentials.