Abstract:

Abstract:Objective
 To explore the reparative effect of bactericidal/permeability-increasing protein(BPI) on the damaged mucosa of rats with  otitis media with effusion (OME)，and state the pathogenesis of OME.
Methods  Wistar rats(40 ears) were randomly divided into six groups:normal control group (n=4),BPI control group(n=4),eustachian tube obstruction (ETO) group (n=8
),lipopolysaccharide (LPS) injection group (n=8), ETO+LPS group (n=8)，ETO+LPS+BPI group (n=8).The experimental OME model was made through eustachian tube obstruction and LPS injection.The rats were killed after 1,2 and 4 weeks and the changes of mucosa of middle ear were observed under light and scanning electron microscope.
Results  The rats in normal control group and BPI control group had the normal mucosa in the tympanic orifice of the eustachian tube.It consisted of pseudostratified ciliated cubical or columnar epithelium which contained an abundant number of ciliated cells and a few goblet cells,these were the mucociliary clearance system of the middle ear.The hypotympanum consisted of thin,squamous epithelium with few microvillus.Middle ear mucosa was obviouly thickened in LPS injection,ETO and  ETO+LPS  groups.An increase in goblet cells and a decrease in ciliated cells were observed in the tympanic orifice of the eustachian tube.The epithelial layer in the hypotympanum had become more pseudostratified ciliated cubical epithelium.In ETO+LPS+BPI group,there was thin squamous epithelium in the hypotympanum near normal,which was not thickened and contained few microvillus.
Conclusion  LPS and  ETO can result in  the occurrence and protracted courses of OME by mimosa’s inflammatory reaction which can reduce the activity of ciliary cells and weaken the  function of mucociliary clearance system.BPI could bind avidly to LPS,reduce inflammatory reaction,and break the inflammatory cycle and reestablish an effective mucocillary clearance system.The  results suggest that  BPI treatment is a potential effective drug  for prevention   and therapy of  chronic OME.

Key words: bactericidal/permeability increasing protein;lipopolysaccharide;
 otitis media with effusion;eustachian tube obstruction