RHEOLOGICAL DETERMINANTS OF MUCOCILIARY TRANSPORT IN THE NOSE OF THE RAT

The present work was designed to investigate whether the theological d eterminants for nasal mucociliary transport are the same in the intact preparation (in situ), as they are when the mucus is added exogenousl y to the isolated, mucus-depleted frog palate (in vitro). We evaluated the association between estimators of mucociliary transport in both c onditions and theological parameters using multiple regression techniq ues. Two kinds of rats were used: (a) specific pathogen free (SPF) rat s, representing the normal condition of respiratory epithelium; (b) no n-SPF rats (NSPF), which have a chronic inflammatory process in the ai rways. In situ mucociliary clearance (MCC) was determined by measuring the displacement of charcoal particles placed in the nasal septum. In vitro mucociliary transport (MCT) of rat nasal mucus was measured usi ng the isolated frog palate preparation. Mucus theologic properties we re determined by magnetic microrheometry, in oscillatory deformations performed at 1, 10 and 100 radians/sec. No differences were detected b etween SPF and NSPF rats in terms of theological parameters. A decreas ed MCC was found in NSPF in comparison with the SPF group, but no diff erences were observed between groups in terms of MCT, as could be pred icted by theological data. When all animals were pooled, in situ trans port was significantly associated with the viscosity/elasticity ratio, whereas in vitro transport was dependent on the total mechanical impe dance of the mucus sample. In conclusion, in situ mucus transport is i nfluenced by other theological parameters than those associated with i n vitro transportability.