Figure 8

IVIg protects primary neurons against HMGB1-induced cell death by modulating TLR signalling cascades. (A-F) Representative immunoblots and quantification illustrating HMGB1 increases the levels of NF-κB-p-p65, p-JNK, p-p38 MAPK and p-c-Jun in primary cortical neurons following 4.5 h of OGD. The increased expression level of p-p65, p-JNK, p-p38 MAPK and p-c-Jun is significantly prevents by administration of IVIg (10 mg/ml) following HMGB1 treatment. Data are represented as mean ± SEM. n = 5 cultures. ⁺ P < 0.05 in comparison with OGD 4.5-h group; ⁺⁺ P < 0.01 in comparison with OGD 4.5-h group; *P < 0.05 in comparison with corresponding OGD group; **P < 0.01 in comparison with corresponding OGD group; ***P < 0.001 in comparison with corresponding OGD group. (G-I) Representative immunoblots and quantification illustrating HMGB1 significantly increases the levels of pro-apoptotic cleaved caspase-3 in primary cortical neurons following 4.5 h of OGD. Administration of IVIg (10 mg/ml) significantly prevents the increased expression levels of cleaved caspase-3 and significantly prevents the decreased expression levels of Bcl-2 following HMGB1 treatment. Data are represented as mean ± SEM. n = 5 cultures. ⁺ P < 0.05 in comparison with OGD 4.5-h group; *P < 0.05 in comparison with corresponding OGD group; ***P < 0.001 in comparison with corresponding OGD group; ns, not significant. (J-L) Representative immunoblots and quantification illustrating the effect of IVIg on the maintenance of intracellular HMGB1 levels and the effect of HMGB1 treatment on the increase in RAGE levels. Administration of IVIg (10 mg/ml) following HMGB1 treatment was able to significantly prevent HMGB1-induced increased of RAGE expression. Data are represented as mean ± SEM. n = 5 cultures. ⁺ P < 0.05 in comparison with OGD 4.5-h group; *P < 0.05 in comparison with corresponding OGD group; **P < 0.01 in comparison with corresponding OGD group; ns, not significant.