Blood-brain barrier (BBB) dysfunction is observed in brain injury including traumatic brain injury (TBI) and stroke. Brain pericytes as well as brain endothelial cells are BBB-constituting cell types and release mediators related to BBB dysfunction under the inflammatory conditions. In the brain injury, the expression levels of PDGFRβ and PDGF-BB, a ligand for PDGFRβ, were increased in brain pericytes at the BBB and brain parenchyma in TBI model mouse, respectively. However, it has not been well known whether activated PDGFRβ signaling in brain pericytes results in the development and deterioration of the brain injury-evoked BBB dysfunction. We, therefore, evaluated whether PDGF-BB-stimulated brain pericytes release mediators associated with BBB dysfunction including matrix metalloproteinase (MMP)-9 and IL-6. Brain pericytes obtained from rat brains were incubated with PDGF-BB (2-20 ng/mL) for 24 h. PDGF-BB treatment significantly increased MMP-9 and IL-6 release from brain pericytes. Furthermore, the downregulation of PDGFRβ signaling with imatinib attenuated PDGF-BB-stimulated MMP-9 and IL-6 release. These findings suggested that brain pericytes may be a key player in the occurrence of brain injury-induced BBB dysfunctions.