A pharmacological and immunopharmacological study on allergic reaction induced by rosin

Dental drugs and dental materials induce several allergic reactions, but our knowledge about the causal substances and the mechanism of allergic reactions is still limited. In this study, we conducted pharmacological and immunopharmacological examinations of rosin, which is included in many preparations, such as pulp capping agents and root canal filling agents. First, we used the adjuvant and patch test in guinea pigs. Twenty-four hours after challenge, erythema was noted in all 3 animals to which we applied 25, 12.5, and 5 % rosin and edema was also noted in one of the animals to which we applied 25% rosin, second, to examine places where rosin causes type IV allergic reactions, the ear swelling test in mice was conducted. At 5 % rosin, the difference was significant ; at 25% rosin, the swelling rate was as high as 55%. From the above two examinations, the results indicated that contact dermatitis, which is type N allergy, may be induced by dental drugs and dental materials containing rosin, and the induction of allergy depended on the concentration of rosin. Third, the kinetics of immunocytes was examined in mice to which we applied 25% rosin in the ear swelling test. The distribution of immunocytes in the ears and lymph nodes was immunohistochemically examined by the indirect enzyme-labeled antibody method. Thy-1.2, CD4, interleukin-2 receptor (IL-2R), IL-4R and CD8-positive cells were detected by light microscopy. The number of IL-4R and CD8-positive cells was increased in the effector phase. It is suggested that Th-2 rather than Th-1 was involved in allergy induced by rosin, and clarified that CD8 positive cells were involved.