TY - JOUR
T1 - Acute ischemia causes 'dark cell' change of strial marginal cells in gerbil cochlea
AU - Ando, Motonori
AU - Takeuchi, Shunji
AU - Kakigi, Akinobu
AU - Raicu, Valericǎ
AU - Yagyu, K. I.
AU - Sato, Takayuki
N1 - Funding Information:
This study was supported by grants from the Ministry of Education, Culture, Sports, Science and Technology, Japan (number 12770020 and 14770003)
PY - 2002
Y1 - 2002
N2 - The cochlear stria vascularis produces the endolymph and generates the endocochlear DC potential, two indispensable ingredients of an auditory transduction process. The marginal cell, one of the several cell types constituting the stria vascularis, is called 'the dark cell' on the basis of its appearance by transmission electron microscopy (TEM). To clarify whether this commonly observed 'dark appearance' is a normal characteristic of marginal cells, as conjectured in the literature, or an experimental artifact, we developed an in vivo fixation method for minimizing ischemic tissue damages. While under sustained systemic circulation with oxygenated blood, the stria vascularis of gerbils was chemically fixed by perilymphatic perfusion with a fixative, and the stria vascularis was observed by TEM. In contrast to a number of previous reports, the cytoplasm of marginal cells was not dark, and quantitative analysis showed that the difference between the cytoplasmic electron density of marginal cells and that of intermediate cells (another type of strial cells) was not statistically significant. For comparison, the gerbils were allowed to undergo 3 min of ischemia following decapitation. Under these conditions, marginal cells showed typical 'dark appearance', as reported previously, and their cytoplasmic electron density was 1.7 times higher than that of the intermediate cells. In addition, the volume of mitochondria in marginal cells undergoing 3 min of ischemia was higher than that fixed in vivo. We therefore conclude that the widely recognized 'dark cell' appearance of marginal cells following conventional fixation procedures reflects cell injury due to ischemia, which is inherent in the standard fixation procedures, but can be avoided by our fixation protocol here introduced.
AB - The cochlear stria vascularis produces the endolymph and generates the endocochlear DC potential, two indispensable ingredients of an auditory transduction process. The marginal cell, one of the several cell types constituting the stria vascularis, is called 'the dark cell' on the basis of its appearance by transmission electron microscopy (TEM). To clarify whether this commonly observed 'dark appearance' is a normal characteristic of marginal cells, as conjectured in the literature, or an experimental artifact, we developed an in vivo fixation method for minimizing ischemic tissue damages. While under sustained systemic circulation with oxygenated blood, the stria vascularis of gerbils was chemically fixed by perilymphatic perfusion with a fixative, and the stria vascularis was observed by TEM. In contrast to a number of previous reports, the cytoplasm of marginal cells was not dark, and quantitative analysis showed that the difference between the cytoplasmic electron density of marginal cells and that of intermediate cells (another type of strial cells) was not statistically significant. For comparison, the gerbils were allowed to undergo 3 min of ischemia following decapitation. Under these conditions, marginal cells showed typical 'dark appearance', as reported previously, and their cytoplasmic electron density was 1.7 times higher than that of the intermediate cells. In addition, the volume of mitochondria in marginal cells undergoing 3 min of ischemia was higher than that fixed in vivo. We therefore conclude that the widely recognized 'dark cell' appearance of marginal cells following conventional fixation procedures reflects cell injury due to ischemia, which is inherent in the standard fixation procedures, but can be avoided by our fixation protocol here introduced.
KW - Electron density
KW - Ischemia
KW - Marginal cell
KW - Mitochondria
KW - Mongolian gerbil
KW - Stria vascularis
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U2 - 10.1007/s00441-002-0597-9
DO - 10.1007/s00441-002-0597-9
M3 - Article
C2 - 12172782
AN - SCOPUS:0036024983
VL - 309
SP - 229
EP - 235
JO - Zeitschrift für Zellforschung und mikroskopische Anatomie (Vienna, Austria : 1948)
JF - Zeitschrift für Zellforschung und mikroskopische Anatomie (Vienna, Austria : 1948)
SN - 0302-766X
IS - 2
ER -