Post-mortem changes at electron microscope level in the type II cells of the lung.

In the type II cells of the lungs of mice, left in the cadaver after death, no post-mortem changes at electron microscope level have been found after 30 minutes. At 1 hour cytoplasmic vesicles have appeared and the microvilli have altered. Vesiculation and nuclear contrast then increase, and after 8 hours at 25° most of the cell is occupied by large vesicles and the cell boundary is disrupted. Meanwhile nuclei, mitochondria and lamellated osmiophilic bodies (LOPBs) remain intact. The timing of the changes is irregular but in these cells they are less rapid than the literature (on other cells) would suggest. Useful information about mitochondria and LOPBs can be obtained even after some hours' delay in fixation. The changes seem to be more rapid if the tissues are immersed in saline than if they are left in the cadaver.