Light and electron microscopic observation of regenerated fungiform taste buds in patients with recovered taste function after severing chorda tympani nerve.
OBJECTIVE
The aim of this study was to evaluate the mean number of regenerated fungiform taste buds per papilla and perform light and electron microscopic observation of taste buds in patients with recovered taste function after severing the chorda tympani nerve during middle ear surgery.


METHODS
We performed a biopsy on the fungiform papillae (FP) in the midlateral region of the dorsal surface of the tongue from 5 control volunteers (33 total FP) and from 7 and 5 patients with and without taste recovery (34 and 29 FP, respectively) 3 years 6 months to 18 years after surgery. The specimens were observed by light and transmission electron microscopy. The taste function was evaluated by electrogustometry.


RESULTS
The mean number of taste buds in the FP of patients with completely recovered taste function was significantly smaller (1.9 +/- 1.4 per papilla; p < 0.01) than that of the control subjects (3.8 +/- 2.2 per papilla). By transmission electron microscopy, 4 distinct types of cell (type I, II, III, and basal cells) were identified in the regenerated taste buds. Nerve fibers and nerve terminals were also found in the taste buds.


CONCLUSIONS
It was clarified that taste buds containing taste cells and nerve endings do regenerate in the FP of patients with recovered taste function.
Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine, University of Fukui, Fukui, Japan.
Takehisa
T
Saito
Tetsufumi
T
Ito
Norihiko
N
Narita
Takechiyo
T
Yamada
Yasuhiro
Y
Manabe
D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001706:Biopsy; D016022:Case-Control Studies; D002648:Child; D002814:Chorda Tympani Nerve / Q000503:physiopathology / Q000601:surgery*; D004432:Ear, Middle / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008853:Microscopy; D008854:Microscopy, Electron; D008875:Middle Aged; D009416:Nerve Regeneration; D020127:Recovery of Function; D013649:Taste; D013650:Taste Buds / Q000473:pathology*; D013997:Time Factors; D014059:Tongue / Q000166:cytology / Q000294:innervation