Adenosine triphosphate modification of endotoxin-induced otitis media with effusion in gerbils

Impairment of the mucociliary system of the middle ear epithelium is a key step in developing otitis media with effusion. Effective propulsion of the viscoelastic gel layer of mucus requires a control of the depth of the periciliary sol layer by means of epithelial ion transport. In a previous study, we successfully demonstrated modulation of ion transport via short-circuit current changes by specific stimulation of adenosine triphosphate (ATP) receptors in a middle ear cell line.

Otitis media with effusion was developed in gerbils by infusing Escherichia coli E.coli lipopolysaccaride. In group A, E. coli lipopolysaccharide was first infused, and after establishment of middle ear fluid, the right ear was infused with 10(-4) M ATP, while the left ear remained as the control. In group B, the right ear was infused first with 10(-4) M ATP followed by bilateral infusion with endotoxin. The morphology of the middle ear mucosa was studied using scanning electron microscopy (SEM).

Group A showed fluid clearance in 5 out of 15 ATP-treated right ears while 3 out of 15 left ears showed clearance. Group B showed persistent presence of fluid in 11 out of 15 ATP-treated right ears, while the left ears showed fluid in 13 out of 15. SEM study consistently demonstrated scanty cilia in the non-ATP treated ears, but in ATP-treated ears the cilia remained abundant.

Although the results showed that ATP could not effectively prevent or clear middle ear effusion, the SEM result showed a marked beneficial effect of ATP on preserving ciliary configuration.