Figure 3.

NLRP1 silencing attenuated neuronal pyroptosis in the APPswe/PS1dE9 brain. Results from 6.5-month-old wild-type (WT) mice and 6.5-month-old APP/PS1 mice after 6 weeks of treatment with the siRNA using a miniosmotic pump. (a) Nissl staining was used to observe neuronal morphology and quantify Nissl-positive cell densities in the cerebral cortex and hippocampus of WT mice and APP/PS1 mice. Representative photos were shown. Scale bars: 20 μm. (b) Comparison of the Nissl-positive cell densities among the experimental groups. Data are shown as mean±S.E.M. obtained from six male mice per group. *P<0.05, compared with the group of APP/PS1 mice treated with control siRNA. (c) Neuronal pyroptosis was detected using the TUNEL staining assay in the cerebral cortex and hippocampus of WT mice and APP/PS1 mice. Neurons with deep black nuclei were identified as TUNEL-positive neurons. Scale bars: 20 μm. (d) Comparison of the percentage of TUNEL-positive cells among the experimental groups. Data are shown as mean±S.E.M. obtained from six male mice per group. *P<0.05, compared with the group of APP/PS1 mice treated with control siRNA. (e) The expression level of caspase-1 (procaspase-1 p45 45 kD and cleaved caspase-1 p20 subunit 20 kD) was analyzed using the western blot assay. A representative immunoblot is shown, and bands of activated caspase-1 p20 were quantified by densitometry, normalized to β-actin. Data are shown as mean±S.E.M. obtained from six male mice per group. *P<0.05, compared with the group of APP/PS1 mice treated with control siRNA. (f) The expression level of cleaved IL-1β (p17) was detected by western blot analysis and quantified by densitometric measurement. β-Actin was used as a loading control. Data are shown as mean±S.E.M. obtained from six male mice per group. NS, not significant. (g) Represent photo of amyloid plaques in cortex and hippocampus of WT mice and APP/PS1 mice treated with control siRNA or NLRP1 siRNA. Amyloid plaques were detected by immunohistochemistry using an antibody against Aβ₄₂. The plaques were visualized by microscopy with × 200 magnification. Scale bars: 100 μm. (h) Quantitative analysis of amyloid plaques among the experimental groups. Data are shown as mean±S.E.M. obtained from six male mice per group. NS, not significant