In middle ear diseases including otitis media with effusion (OME), there are various lipids mediators such as leukotoriene C4, D4 (LTC4, LTD4) and prostaglandin E2 (PGE2) in the effusion of the tympanic cavity. Therefore, it is important to examine the effect of these mediators on middle ear clearance. We studied on the effect of LTC4, LTD4 and PGE2 on mucociliary transport of the eustachian tube both in vitro and in vivo. Healthy guinea pigs with normal Preyer's reflexes were used in vitro study. Normal ciliated epithelium was carefully obtained from the tubotympanium and incubated with RPMI solution in the from of tissue culture. The epithelial specimens were incubated with LTC4, LTD4 and PGE2 respectively, ranged at the concentrations of 10-8M and 10-6M. Ciliated cells of the specimens were observed under an inverted microscope. Ciliary activity of each ciliated cell was photo-electrically measured on a TV monitor. LTC4 and LTD4 inhibited ciliary activity at the concentrations of 10-8M and 10-6M in vitro. PGE2 promoted ciliary activity at the concentrations of 10-8M and 10-6M. Healthy chinchillas were used in vivo study. The animals were free of middle ear infection and hearing loss as determined by otomicroscopy, tympanometry and auditory brainstem response (ABR). One ml each of 10-5M LTC4, LTD4, PGE2 and the control solution (10-3 ethanol/saline) was directly injected into the tympanic bulla with a 27-gauge syringe under anesthetization. The middle ears were examined by otomicroscopy, tympanometry and ABR across time. LTC4 and LTD4 inhibited mucociliary transport of the eustachian tube. However, there was no significant difference between PGE2 and the control.
