Expression of aquaporin1, 3, and 4, NKCC1, and NKCC2 in the human endolymphatic sac.
OBJECTIVE
To locate aquaporin (AQP) 1, 3, and 4, Na-K-2Cl cotransporter (NKCC) 1 and 2 in the human endolymphatic sac (ES).


METHODS
A sample of human ES was harvested during the removal of vestibular schwannoma via the translabyrinthine approach. The sample was immediately fixed in 4% paraformaldehyde and embedded in OCT compound. Immunohistochemistry was performed with AQP1, 3, and 4, NKCC1, and NKCC2 polyclonal antibodies.


RESULTS
AQP1, AQP3, and NKCC2 were strongly expressed in the epithelial layer of the ES. AQP4 and NKCC1 were weakly expressed in the epithelial layer of the ES.


CONCLUSIONS
As it is impossible to perform quantitative analysis based on the fluorescence intensity of each immunoreactivity, we have presented the existence of AQP1, 3, and 4, NKCC1, and NKCC2 in the ES. The expression of NKCC1 and 2 indicated that the ES may have both secretory and adsorptive functions to maintain the homeostasis of endolymph.
Kakigi
Akinobu
A
Department of Otolaryngology, Kochi Medical School, Nankoku, Japan. kakigia@kochi-u.ac.jp
Nishimura
Masahiko
M
Takeda
Taizo
T
Taguchi
Daizo
D
Nishioka
Rie
R
D051398:Aquaporin 1 / Q000032:analysis*; D051400:Aquaporin 3 / Q000032:analysis*; D051401:Aquaporin 4 / Q000032:analysis*; D004712:Endolymphatic Sac / Q000473:pathology*; D004848:Epithelium / Q000473:pathology; D006801:Humans; D008856:Microscopy, Fluorescence; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery; D028021:Sodium-Potassium-Chloride Symporters / Q000032:analysis*; D064466:Solute Carrier Family 12, Member 1; D064506:Solute Carrier Family 12, Member 2
C496027:AQP3 protein, human; C496030:AQP4 protein, human; D051401:Aquaporin 4; C578714:SLC12A1 protein, human; C578877:SLC12A2 protein, human; D028021:Sodium-Potassium-Chloride Symporters; D064466:Solute Carrier Family 12, Member 1; D064506:Solute Carrier Family 12, Member 2; D051398:Aquaporin 1; D051400:Aquaporin 3