A morphological study of TUNEL positive dying cells in the developing inner ear of mouse embryos- CDDP-induced change- *
In the recent studies of cell death, dying cells judged by the TdT-mediated dUTP nick end-labeling (TUNEL) method have been classified into "apoptotic" and "non-apoptotic" cells. In this study, 12-day-old mouse embryos were used. The percentage of "apoptotic" and "non-apoptotic" cells among total dying cells in inner ear were calculated, and the effects on inner ear's cell death of cis-diammine-dichloroplatinum (CDDP) were examined. Five inner ears from normal embryonic mice (Control group) and five inner ears from CDDP treated embryonic mice (CDDP group) were used. TUNEL positive dying cells occurring in apoptotic cell death (ACD) and non-apoptotic cell death (NACD) were classified by light microscopy, and the numbers in ACD and NACD in the whole inner ear were counted. About 90% of the inner ear dying cells of the Control group were ACD and about 10% were NACD. About 70% of the inner ear dying cells in the CDDP group were ACD and about 30% were NACD. It was suggested that ACD essential to development of inner ear, and increased NACD might be defensive phenomenon against CDDP toxicity. (Accepted on October 28, 2002) Kawasaki Igakkaishi 28 (4 ) : 287-296, 2002
