Albumin stimulated an increase in the release of MMP-9 released in the conditioned media by astrocytes. Astrocytes were exposed to control PBS (−) or BSA (+). The conditioned media were collected after 0.5, 1.5, 6 and 24 hours and analyzed by gelatin zymography. (a) Representative zymogram showing a time-dependent increase in matrix metalloproteinase (MMP)-9; (b) there was a significant increase in the level of MMP-9 released 24 hours after BSA treatment compared with the control group; (c) the level of MMP-2 measured after BSA treatment was similar to that of the control group at all time points; (d) treatment with fraction V (FrV) BSA also induced an increase in the level of MMP-9 released from astrocytes. Human serum albumin (HSA) and rat serum albumin (RSA) induced a similar increase in MMP-9 level to that seen with BSA. Treatment with dextran (0.1 mmol/L) did not induce any change in the level of MMP-9 in astrocytes. Data are representative of mean ± SEM of three independent experiments. ***P < 0.001 compared with control group, by two-way ANOVA.