Figure 5

Erk1/2 and p38 MAPK pathways are involved in MMP-9 secretion by HKBA- or L-Omp19-stimulated astrocytes. Astrocytes were incubated with inhibitors of MAPK pathways (PD: inhibitor of Erk1/2; SB: inhibitor of p38) two hours before the beginning of culture and kept throughout. Culture supernatants were harvested at 48 hours post stimulation with HKBA, L-Omp19 and Pam₃Cys to assess the expression of MMP-9 by zymography (A) and (B). The net gelatinase activity was expressed in fluorescence units informed by the fluorometer (C, D and E). Pam₃Cys was used as a positive control. Bars express the mean ± SEM of duplicates. Data shown are from a representative experiment of four performed. NS: non-stimulated astrocytes. *P < 0.05, **P < 0.01, ***P < 0.001 versus untreated (minus sign); and P < 0.05 versus the treatment with PD or SB alone (black star).