Fig. 7

Inhibition of interleukin converting enzyme caspase 1 (with N-Acetyl-TRP-GLU-His-Asp-AL at 0.67 mg/mL) or neutralization of IL-1β activity decreases microglial activation. Representative images from cultures expressing P2X7R-EGFP without (a) or with (b) IL-1β neutralization. Top panels: green, P2X7R-EGFP, red, isolectin GS-IB₄, blue, DAPI nuclear stain. Bottom panels: green, P2X7R-EGFP, blue, DAPI nuclear stain. Scale bars, 20 μm. c Primary hippocampal cultures expressing P2X7R-EGFP with caspase 1 inhibited (caspase 1−) (n = 40) showed a decrease in total number of cells (DAPI positive) compared to the P2X7R-EGFP-expressing control (caspase 1+) (n = 40) cultures with no caspase 1 inhibition. d The number of transfected cells expressing P2X7R-EGFP was smaller in cultures where caspase 1 was inhibited (caspase 1–) (n = 40) compared to the controls (caspase 1+) (n = 40) with no inhibition of caspase 1. e The absolute number of microglia per imaging field was decreased in the P2X7R-EGFP-expressing cultures with caspase 1 inhibited (caspase 1−) (n = 40) compared to the controls (caspase 1+) (n = 40). f Primary hippocampal cultures expressing P2X7R-EGFP with IL-1β activity neutralized (IL-1β−) with the aid of a neutralizing antibody (n = 40) showed a decrease in the total number of cells (DAPI positive) compared to the P2X7R-EGFP-expressing control (IL-1β+) (n = 40) cultures with no IL-1β neutralization. g As a proportion of the total microglial pool (identified by isolectin GS-IB₄ and DAPI nuclear counter-staining) less activated microglia were evident in cultures expressing P2X7R-EGFP (n = 40) with the activity of IL-1β neutralized (IL-1β–) compared to the controls with no neutralization (IL-1β+) (n = 40). h The absolute number of microglia per imaging field was decreased in the P2X7R-EGFP-expressing cultures with IL-1β neutralization (IL-1β−) (n = 40) compared to the controls (IL-1β+) (n = 40). Imaging field dimension, 230 × 230 μm. *p < 0.05, Student’s t test