2.4 Nissl staining
Nissl staining was carried out using a Nissl stain Kit (Solarbio, # G1430, China). Brain sections were dried at 60°C and stained with Reagent A (Cresyl violet Stain) for 1 h at 56°C. Subsequently, the sections were washed with distilled water, immersed in Reagent B (Nissl Differentiation) for seconds to 2 min, and dehydrated in absolute ethanol. Finally, the sections were cleared in xylene before being cover-slipped with neutral balsam (Solarbio, # G8590, China).