Fig. 6

MCC at EoT and EoR in inserts exposed to test items for either 4 or 24 h. Isoproterenol is a positive control, known to enhance MCC through its stimulatory effect on ciliary beating. *p < 0.05 relative to untreated inserts at the corresponding timepoint (EoT or EoR). §p < 0.05 relative to the same treatment at EoT.