Bio-morphological studies of apoptotic with non-apoptotic dying cells in developing inner ear of mouse embryos.

tdt介导的dUTP缺口末端标记（TUNEL）方法研究的死亡细胞分为“凋亡”细胞和“非凋亡”细胞。在这项研究中，由于内耳形态变化导致的“自然细胞死亡”频率很高，因此使用12日龄小鼠胚胎，计算了内耳死亡细胞总数中“凋亡”和“非凋亡”死亡细胞（ADC和NADC）的百分比。连续石蜡切片观察，对照组死亡的内耳细胞中90%为ADC， 10%为NADC。顺式二胺-二氯铂（CDDP）组内耳死亡细胞中ADC占70%，NADC占30%，光镜下树脂切片中ADC和NADC TUNEL阳性死亡细胞采用重包埋法透射电镜观察。然后根据Clarke描述的死亡细胞分类（1、2、3A和3B型）对ADC和NADC进行分析。很明显，ADC相当于1型（凋亡）死亡细胞，NADC相当于2型（自噬）死亡细胞。无3A或3B型细胞死亡。提示ADC对内耳发育至关重要，NADC的增加可能是对CDDP毒性的防御现象。我们认为这些发现是确定内耳异常发育过程及其功能障碍（如听力损失）的重要基线。

Dying cells studied the TdT-mediated dUTP nick end-labeling (TUNEL) method have been classified as ‘apoptotic' and ‘non-apoptotic' cells. In this study, in which 12-day-old mouse embryos were used because of a high frequency of ‘natural cell death' due to changing inner ear morphology, the percentages of ‘apoptotic' and ‘non-apoptotic' dying cells (ADC and NADC) among total dying cells in the inner ear were calculated.Observation of consecutive paraffin sections showed 90% of the dying inner ear cells to be ADC and 10% to by NADC in the control group. 70% of the inner ear dying cells were ADC and 30% were NADC in the cis-diammine-dichloroplatinum (CDDP) group ADC and NADC TUNEL positive dying cells in resin sections observed by light microscopy were examined again by transmission electron microscopy using a re-embedding procedure. ADC and NADC were then analyzed based on the classification of dying cells (type 1,2,3A and 3B) as described by Clarke. It was clear that ADC were the equivalent of type 1(apoptotic) dying cells and NADC were the equivalent of type 2(autophagic) dying cells. No type 3A or 3B cell death occurred. It was suggested that ADC essential to development of inner ear, and increased NADC might be defensive phenomenon against CDDP toxicity. We consider these finding to be important baselines for determining the process underlying abnormal development of the inner ear and its functional disorders such as hearing loss.