Nissl staining solution cresyl violet

In experiment I, we detected pathological changes in the basal forebrain and hippocampus in 6- and 8-month-old APP/PS1 mice. The WT and AD mice groups were anesthetized with 1% pentobarbital sodium (0.05 g/kg i.p.). Saline and 4% paraformaldehyde were perfused from the left ventricle to, respectively, wash and fix the brain tissue. Then coronal slices of the brain tissue were prepared for pathological staining, using 5μm per section. To perform Thioflavin S staining, the tissues were placed in 0.3% Thioflavin S solution (Thioflavin S, Sigma, T1892) and then differentiated in 50% ethanol. Nissl staining was performed with Nissl Staining Solution (Nissl Staining Solution (Cresyl Violet), Solarbio, G3410) according to the manufacturer’s instructions.

Anesthetized mice (pentobarbital sodium [0.05 g/kg i.p.]) were perfused with saline to wash out the blood and were then perfused with 4% paraformaldehyde to fix the brain tissue. The brain tissue was embedded in paraffin and 5 μm coronal slices of brain tissue samples were prepared for pathological staining. For ThS staining, the brain sections were routinely deparaffinized, hydrated, placed in 0.3% ThS solution (Thioflavin S, Sigma, T1892) for 8 min, and differentiated in 50% alcohol for 3 × 5 min. For Nissl staining, the brain sections were routinely deparaffinized and hydrated, and the sections were incubated for 1 h at 56°C with A reagent (Nissl Staining Solution (Cresyl Violet), Solarbio, G3410). The brain sections were then incubated in B reagent for 2–3 min. Finally, the brain sections were sealed with neutral resin and photographed under a microscope.

After fixation with 4% paraformaldehyde, tissue paraffin 4 μm slices were conventional dyed with hematoxylin and eosin (H&E) and Nissl staining and immunohistochemistry were conducted to analysis the histopathological condition around the injury site. Nissl staining was conducted by Nissl Staining Solution (Cresyl Violet) (Solarbio Science & Technology Co., Ltd., Beijing, China). The brain sections were incubated with Nlrp3 antibody (ab270449, Abcam, 1:100) overnight at 4°C, incubated with HRP-linked secondary antibody (ASR1651, Abcepta), and stained by DAB solution. Microscopic observation of the histological slides was performed using a light microscope (10× objective). Both Nissl-positive cells in randomly three fields of primary somatosensory cortex around the injury site (parietal cortex) per brain were counted by the ImageJ software (1.4, NIH).