Transplantation of MSC decreased the levels of matrix metalloproteinase-9 (MMP-9). Western blotting analysis of MMP-9. Treatment with MSCs downregulated the levels of MMP-9 24 and 72 h after ICH when compared with the PBS-treated group (A, B). n = 6 in each time point per group. Data are presented as the mean ± SD. *P < 0.05. GAPDH, glyceraldehyde 3-phosphate dehydrogenase; MMP-9, matrix metalloproteinase 9; MSCs, mesenchymal stem cells; PBS, phosphate-buffered saline.