A CRITICAL-APPRAISAL OF INTRATRACHEAL INSTILLATION OF BENZO[A]PYRENE TO SYRIAN GOLDEN-HAMSTERS AS A MODEL IN RESPIRATORY-TRACT CARCINOGENESIS

Several experimental models have been developed to study respiratory t ract carcinogenesis. The most widely applied in vivo model uses Syrian golden hamsters which receive intratracheal instillations of a suspen sion of benzo[a]pyrene (B[a]P) particles attached to ferric-oxide (Fe2 O3) particles in saline; it was first described by Saffiotti et al. [1 ]. This model has several benefits compared with other experimental mo dels; however, the large number of variables affecting the tumour resp onse is a clear disadvantage because the tumour response is difficult to control. In this review, we describe a systematic analysis of vario us variables that may influence the tumour response of the respiratory tract with the aim to further standardize the method and increase, th rough that, its suitability and predictabilty. The most important vari ables influencing the tumour response, as shown by statistical analysi s of 29 representative studies, turned out to be the administered dose and the particle size. Both these variables influence the actual dose and the contact-time of the B[a]P particles with the target cells. Th e present study does not support the widespread opinion that ferric-ox ide particles enhance the tumour response of the respiratory tract. In conclusion to the present analysis, some recommendations are made whi ch probably increase the predictability of the model.