Distribution of Mast Cells in the Rat Tympanic Membrane and Eustachian Tube

Yoon, Yong Joo; Jeong, Woo Cheol; Jeong, Kyoung Soo

Abstract

BACKGROUND AND OBJECTIVES: Mast cells are widely distributed in the loose connective tissue and their predilection sites are the portals of entry into the host. It seems possible that mast cells play an important role in the eustachian tube as a gate of the middle ear cavity. The purpose of this study was to investigate the distribution of mast cells in the rat tympanic membrane and eustachian tube.
MATERIALS AND METHODS
The tympanic membrane and eustachian tube of rats (5) were used in this study. The specimens of formalin-fixed paraffin-embedded tissues (4 micrometer) were observed by staining with toluidine blue.
RESULTS
In the tympanic membrane mast cells were observed mainly just beneath the keratinizing stratified squamous epithelium of the tympanic membrane. Mast cells were also distributed in the connective tissue of the eustachian tube. Most of the mast cells were found adjacent to vessels and glands. The density of mast cells beneath the mucosal epithelium of the eustachian tube was significantly lower than that in deep connective tissue layer. Their presence in the eustachian tube was less prominent than in the tympanic membrane.
CONCLUSION
It seems reasonable to suggest that mast cells in the tympanic membrane and eustachian tube are important in responding to continuous stimuli of the tympanic cavity.