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Histopathological analysis of brain slices following a stroke

Today in the lab I was analysing H&E stained brain slices to identify histopathological changes following a stroke. H&E-stained brain tissue was examined under a light microscope. The soma of healthy unaffected neurons appeared round with a clearly visible nucleus. On the other hand, ischaemic neurons appeared dark and shrunken, with pyknotic nuclei. In addition, eosin staining appeared paler and there was vacuolation of the neuropil. There was also a massive infiltration of neutrophils, and oedema was clearly visible. An example of the type of images I collected using the microscope are shown below.

Timelapse: Looking at the stained brain slices under a light microscope.

Light microscopic images (x40 magnification) of H&E-stained brain tissue following a stroke. The left image shows unaffected tissue from the ipsilateral hemisphere. The right image shows the infarct.
Light microscopic images (x40 magnification) of H&E-stained brain tissue following a stroke. The left image shows unaffected tissue from the ipsilateral hemisphere. The right image shows the infarct.

T2-weighted MRI images 7 days post-stroke and diagrams of corresponding coronal slices. The infarct area as observed by light microscopic examination of H&E-stained sections was manually drawn onto the diagrams and is shown in red.
T2-weighted MRI images 7 days post-stroke and diagrams of corresponding coronal slices. The infarct area as observed by light microscopic examination of H&E-stained sections was manually drawn onto the diagrams and is shown in red.

Detailed methods of today’s experiment

An approximation of the infarct area as seen on H&E-stained sections under the light microscope was manually drawn onto diagrams of corresponding coronal slices from a brain atlas, which were then scanned to a computer and analysed using image analysis software. The area of the drawn infarct was manually delineated in the same way as for T2-weighted MRI images, but without oedema correction. The infarct area from each diagram was compared with the oedema-corrected and uncorrected infarct areas from the corresponding slices from T2-weighted MRI images from the same brain, to determine the accuracy of measuring the infarct from MRI images. Oedema-corrected infarct areas from T2-weighted images were calculated using previously published equations. Lesion areas calculated from diagrams were significantly smaller than those calculated from T2-weighted images before oedema correction.