Fig 2.

Peptidylarginine deiminase (PAD) inhibition reduces neuronal loss and histone deimination. PAD inhibition results in reduced infarct volume (a) and cell death (b) 48 h following lipopolysaccharide (LPS) sensitized hypoxic ischaemic (HI) (LPS/HI) insult (n = 10 per group). (a) For tissue loss, significant differences were seen in the overall PAD inhibition [Cl-amidine (CA)] treatment (p = 0.007), with some post hoc evidence of subregion differences in the hippocampus and external capsule (p = 0.059 and p = 0.013 respectively) (b) Following PAD inhibition (CA) cell death was significantly reduced overall (p < 0.001), with post hoc evidence of subregion reduction in cortex, pyriform cortex and striatum (p < 0.001, p = 0.019, p = 0.003), with some post hoc evidence of an effect in hippocampus and thalamus (p = 0.062, p = 0.058). (c, d) Nissl-stained brains of the LPS/HI animals post-treated with saline (sal) show massive tissue loss on the occluded side (left) in the cortex, hippocampus, striatum and external capsule (c); those post-treated with Cl-amidine (CA, 1 × 30 μg/g 10 min after LPS injection and again 1 × 30 μg/g immediately after 30-min hypoxia) result in a greatly reduced infarct (d). c1 (boxed region in c): Massive increase in deiminated histone 3 immunoreactivity (citH3) is observed 48 h following combined LPS/HI insult, and post-treatment with saline. d1 (boxed region in d): CitH3 is suppressed in LPS/HI animals treated with Cl-Amidine. c2 (higher magnification of c1): Histone deimination is observed in the nucleus (arrowheads) and cellular cytoplasm (arrows) in the damaged cerebral cortex in LPS/HI animals. d2 (higher magnification of d1): Both types of citH3 immunoreactivity are suppressed in LPS/HI animals treated with Cl-amidine and absent in control 30 min HI alone (e). Scale bars: c & d: 1 mm; c & d1 = 250 μM; c,2 d2 & e = 100 μM; *p < 0.02.