Subacute Effects of Capsaicinoids on the Distribution of White Blood Cells in Rats

The subacute effects of dihydrocapsaincin (DHC) and capsaicin (CAP) (dose = 3 mg/kg body weight per day for 10 days, subcutaneous) on the number and distribution of white blood cells (WBCs) were studied in male adult rats. The administration of DHC and CAP for 10 days decreased significantly the number of total WBCs, lymphocytes and monocyte, and increased significantly the number of the neutrophil and eosinophil without changing the number of basophil. The administration of DHC significantly decreased thymus weight and increased adrenal weight, showing that DHC induced thymus atrophy and adrenal hypertrophy. These results suggest that capsaicinoids induced the decrease of acquired immunity responses and these phenomena may have in part participated in capsaicinoids-induced stress-responses in rats.