Comparison of scanning electron and light microscopic appearances of sequential changes taking place in the ischemic...

The right middle cerebral territory of rat brains was made ischemic (a) for periods varying from 30 minutes to 24 hours, and at the end of each of the times the animals were killed and their brains were fixed, or (b) for 30 minutes, and the animals were allowed to survive for between 1 week and 9 months before they were killed and their brains were fixed. The ischemic areas were examined by light and scanning electron microscopy and the findings of the two methods of examination were compared. Scanning electron microscopy allowed the tissues to be studied at a wider range of magnification than was possible with the light microscope. Scanning electron microscopy also provided a three-dimensional view of the structures so that their relationship to one another could be examined. However, because it is generally not possible to stain material for examination by scanning electron microscopy, it was sometimes difficult to identify positively the individual structures. Nevertheless, this study has shown that scanning electron microscopy provides a valuable new way of investigating the ischemic brain and is likely to prove useful in other studies in the future.