Induction of apoptosis in the vestibule of guinea pigs after middle ear inoculation with lipopolysaccharide (LPS).
OBJECTIVE
During the process of apoptosis, double-stranded DNA is broken into single-stranded DNA (ssDNA) by the action of caspases and caspase activated deoxyribonuclease (CAD). We immunohistochemically examined the apoptotic changes induced by endotoxin in the vestibule of guinea pigs.


METHODS
Lipopolysaccharide (LPS) (5 mg/ml, 0.2 ml), a bacterial endotoxin, was transtympanically injected into the middle ear. 48 h after injection of LPS, animals were sacrificed by intracardiac perfusion of fixative. The temporal bones were then removed and immunohistochemically stained for ssDNA, CAD and caspase 3.


RESULTS
ssDNA was detected after 48 h in the dark cell area of the LPS group, not in the sensory epithelium. CAD was observed both in the dark cell area and the sensory epithelium. Caspase 3 was also detected both in the dark cell area and the sensory epithelium.


CONCLUSIONS
Our findings suggest that apoptosis is involved in the dysfunction of the vestibule under inflammatory conditions.
Watanabe
Ken-ichi
K
Department of Oto-Rhino-Laryngology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 113-8603, Tokyo, Japan. bxp02646@nifty.ne.jp
Jinnouchi
Ken
K
Inai
Shunta
S
Yagi
Toshiaki
T
D000818:Animals; D000970:Antineoplastic Agents / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002945:Cisplatin / Q000633:toxicity; D004277:DNA, Single-Stranded / Q000187:drug effects; D003851:Deoxyribonucleases / Q000378:metabolism; D006168:Guinea Pigs; D007150:Immunohistochemistry; D007668:Kidney / Q000166:cytology / Q000187:drug effects; D008070:Lipopolysaccharides / Q000378:metabolism / Q000633:toxicity*; D014722:Vestibule, Labyrinth / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D000970:Antineoplastic Agents; D004277:DNA, Single-Stranded; D008070:Lipopolysaccharides; D003851:Deoxyribonucleases; C109663:caspase-activated deoxyribonuclease; D053148:Caspase 3; D020169:Caspases; D002945:Cisplatin