Fig. 9

PAR-2 activation reversed the anti-neuroinflammatory effects of APC366 at 24 h after ACA. Representative western blot images and quantitative analysis of MC-tryptase (a), PAR-2 (b), p38 (c), p-p38 (d), NFκB (e), and proinflammatory cytokines (f, g) in the brain at 24 h following ACA. The levels of the pathway proteins were markedly increased following ACA. The inhibition of MC-tryptase significantly reduced PAR-2, p-p38 and NFκB, TNF-α, and IL-6 levels in rats treated with APC366 compared to the ACA + vehicle group. Further activation of PAR-2 by AC55541 caused higher expressions of p-p38, NFκB, and proinflammatory cytokines compared to the vehicle-treated ACA group. The co-administration of APC366 and AC55541 not only abolished the protective effect of APC366 in ACA rats, but also offset the detrimental effects of pharmacological activation of PAR-2 by AC55541, resulting in significantly lower levels of p-p38, NFkB, IL-6, and TNF-a compared to AC55541 alone. Selective p38 inhibitor, SB203580 reversed the aggravated neuroinflammation due to AC55541 by decreasing the expressions of p-p38, NFκB, IL-6, and TNF-α. h Neurologic deficit score at 24 h following ACA. The inhibition of MC-tryptase significantly improved neurologic function. This effect was reversed with the activation of PAR-2 by AC55541 at 24 h following ACA. The activation of PAR-2 by AC55541 alone significantly worsened neurological performance; however, this effect was rescued by the p-38 inhibitor, SB203580, compared to the ACA + vehicle group. Data are expressed as mean ± SD. n = 6/group. ANOVA, Tukey. **p < 0.001 compared to sham, *p < 0.05 compared to sham, &&p < 0.001 compared to ACA + vehicle, &p < 0.05 compared to ACA + vehicle, $p < 0.05 compared to ACA + APC366 (50 μg), %p < 0.05 compared to ACA + APC366 (50 μg) + AC55541 (30 μg), #p < 0.001 compared to ACA + AC55541 (30 μg), ##p < 0.05 compared to ACA + AC55541 (30 μg)