[In vitro studies of the effect of papain on isolated chondrocytes: clinical relevance for correction of structural abnormalities of the ear].
A permanent change of shape of the auricle can be achieved by local application of papain to the elastic cartilage. To assess possible clinical use of papain, we investigated its effect on isolated and cultured chondrocytes derived from human cartilage of the auricle. We determined cellular vitality using the trypan blue method. The release of the cytokines IL-1 alpha and IL-6 measured by ELISA and HLA-DR antigen expression evaluated by histological procedures was used as a parameter of the state of activation of chondrocytes. Cell proliferation was also determined by the number of Ki-67 positive cells. A papain concentration above 160 micrograms/ml led to decreasing vitality and number of proliferating cells. A papain concentration above 160 micrograms/ml solvent led to expression of HLA-class-II-antigen on the surface of the chondrocytes. The release of IL-6 was reduced depending on the concentration of papain. However, IL-1 alpha was detected in low concentration with and without application of papain. These investigations show for the first time that papain not only leads to direct destruction of the matrix as described in literature, but also influences the integrity of the matrix by the function and state of activation of chondrocytes. A concentration of papain above 160 micrograms/ml should not be exceeded in clinical application.