Nissl Staining for Neuronal Survival Assessment

Nissl staining was performed to assess neuronal survival after MCAO. Coronal cryosections with a thickness of 3 μm were stained with Nissl staining solution (C0117, Beyotime, Shanghai, China) at 37 °C for 5 min on day 3 after modeling. The samples were washed with 95% ethanol for 5 min and dried. The sections were then washed twice in xylene for 5 min each. After being sealed with resin, the cytoplasm was stained blue–purple (Nissl bodies), and the nuclei were stained light blue–purple when viewed under a light microscope. Normal neurons have relatively large cell bodies, are rich in cytoplasm and have a large number of Nissl bodies, with one or two large round nuclei, whereas damaged cells have shrunken cell bodies, condensed nuclei, reduced or no Nissl bodies, dark cytoplasm and many vacuoles.