Histological study on postmortem changes and the influence of the cause of death in various organs.

1997 Fiscal Year Final Research Report Summary

• Project/Area Number: 07670506
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Legal medicine
• Research Institution: Nippon Medical School
• Principal Investigator: TOMITA Yukari Nippon Medical School, Medical department, Assistant, 医学部, 助手 (20159049)
• Co-Investigator(Kenkyū-buntansha): SATO Shigeru Nippon Medical School, Medical department, Assistant, 医学部, 助手 (10125073) ; NIHIRA Makoto Nippon Medical School, Medical department, Assistant Professor, 医学部, 助教授 (40089636) ; OHNO Youkichi Nippon Medical School, Medical department, Professor, 医学部, 助教授 (70152220)
• Project Period (FY): 1995 – 1997
• Keywords: postmortem changes / histological study / cervical dislocation / excessive bleeding / clumping of chromatin / swelling and degeneration of mitochondria / estimation of postmortem interval / transmission electron microscopy

Research Abstract

Male Wistar rats were killed by cervical dislocation or exsanguination and left at room temperature up to twenty-four hours after death. After given postmortem interval, kidney, pancreas, liver, heart and skeletal muscle were embedded by paraffin or epoxy resin and examined by light microscopy. For ultrastructural examination, epoxy embedded block was examined by transmission electron microscopy.
1. From the light microscopic study in cervical dislocation group, the specimen obtained from epoxy block reflects the postmortem interval by the appearance of the clumping of chromatin in nucleus and the vacuolization in cytoplasm. In addition, the time-courses of postmortem changes were characteristic in each organ up to twenty-four hours after death. On the other hand, the specimen from paraffin block showed no significant histological differences. These phenomena estimate the proceeding of postmortem changes during the fixation period in paraffin embedding method.
2. From the ultrastructural examination of the cervical dislocation group and the exsanguination group, the postmortem changes were delayd in exsanguination group. In pancreatic acinar cell, the mitochondrial amorphous dense deposits were hardly seen at three hours after death and were slightly seen at ten hours after death by exsanguination, while the deposits were seen at one hour after death and the mitochondria showed amorphism at ten hours after death by cervical dislocation. The myocardium showed relaxation at three hours after death, contraction at ten hours after death, and relaxation again at fifteen hours after death by cervical dislocation, while relaxation and contraction were seen simultaneously at ten hours after death by exsanguination.These phenomena might be caused by the rapid falling of rectal temperature in exsanguination group.
3. From the ultrastructural observation of cervical dislocation group, clumping of chromatin, amorphous dense deposits of mitochondria are useful for morphological assessment for the estimation of postmortem interval.