ObjectiveTo observe the relationship between neuronal function score and pathological changes of fluid percussion brain injury in rats and to explore their clinical significances.MethodsThe fluid percussion models of brain injury in rats were established by using the improved device with three kinds impact pressure such as 0.1 MPa,0.2 MPa,0.3 MPa,and vital signs and mortality rate were observed.Behavior changes,brain water content,histological changes were observed by Shapira and Wahld method,dry-wet measure,light microscopy at 1 h,6 h,12 h,24 h,3 d and 7 d after operation respectively.ResultsThe animals accepted impact pressure of 0.1 MPa showed temporary hypopnea with mortality rate of 2.08％,those of 0.2 MPa suffered apnoea of ( 10.88 ±2.69 ) s with mortality rate of 4.17％ and those of 0.3 MPa suffered apnoea of ( 20.60 ± 3.02 ) s with mortality rate of 16.67％.As the impact pressure increased,nervous function score minimumly decreased to (7.17 ±0.75) of 0.1 MPa group,(4.83 ± 0.75 ) of 0.2 MPa group and (2.67 ± 0.52) of 0.3 MPa group respectively,and recovered more slowly.Brain water content maximumly reached to (81.12 ± 0.03 )％,(82.74 ± 1.11 )％ and (83.89± 0.04) ％ at time point of 24 h respectively.The brain injury was involved in the outer layer of cerebral cortex,hippocampal formation and brain stem respectively and histological observation verified above findings.Conclusion Light,moderate and heavy fluid percussion brain injury in rats have more and more low nervous function scores,which have positive relationship with more and more serious pathological changes.