MMP9 and brain injury: It is of note that expression of NF-kB and MMP-9 and increased activity of MMP-9 were prevented by non-toxic doses of intraperitoneal cyclosporine for 7 days (15 min post-injury bolus dose: 20 mg/kg, the next 6 days: 10 mg/kg/day; Figure 3), suggesting that cyclophilin A led to BBB disruption (Figure 1) in hypertensive rats after mild brain trauma via the NF-kB-MMP-9 pathway.