Objective To investigate the effects of basic fibroblast growth factor (bFGF) on pericytes in the blood brain barrier at acute stage after traumatic brain injury (TBI) in mice.Methods A total of 90 mice with a C57BL/6 background were randomly divided into sham group,TBI group,and TBI + bFGF group,with 30 rats per group.The models of moderate TBl were established using the controlled cortical impactor.After 24 hours,the changes of nerve function were evaluated by Garcia neurological score.Each mouse received an intraperitoneal injection of Evans blue dye for measuring the permeability of blood brain barrier.Western blot was used to test the related indices of pericytes after the cerebral cortex was quickly dissected:platelet-derived growth factor receptor beta (PDGFR-β),aminopeptidase N (CD13),desmin,neurogliocyte 2 (NG2),and glyceraldehyde-3-phosphate dehydrogenase (GAPDH).Paraffin sections were prepared for HE staining and morphological changes were observed.Immunofluorescence assay was used to test the related indices of pericytes:PDGFR-β,CD13,and cell surface glycoprotein MUC18 (CD146).Results Garcia neurological score revealed that the score in TBI group was significantly decreased compared with that in sham group (P ＜ 0.01),but the score of TBI + bFGF group was significantly increased compared with that of TBI group (P ＜ 0.05).Permeability of blood brain barrier in TBI group was significantly increased compared with that in sham group (P ＜0.01),but in TBI + bFGF group this parameter significantly reduced compared with that in TBI group (P ＜ 0.01).Western blot analysis revealed that the expressions of PDGFR-β,CD13,desmin,NG2 proteins in TBI group were significantly decreased compared with those in sham group (P ＜0.05),while the expressions of PDGFR-β,CD13,desmin,NG2 proteins in TBI + bFGF group were significantly increased compared with those in TBI group (P ＜ 0.05).HE staining revealed injury of brain parenchyma in TBI group was the severest compared with both sham group and TBI + bFGF group.Immunofluorescence staining results revealed that the proteins expressions of PDGFR-β,CD13,and CD146 in TBI group were significantly decreased compared with those in sham group (all P ＜0.01),and those in TBI + bFGF group were significantly increased compared with those in TBI group (all P ＜ 0.05).Conclusions bFGF can prevent pericyte death via protecting its proteins to conserve blood-brain barrier,bFGF can also significantly ameliorate the injury of brain parenchyma.