Establishment of graded fluid percussion model of experimental brain injury in rats

Objective To establish the graded fluid percussion models of brain injury in rats and compare their pathological changes.Methods The fluid percussion models of brain injury in rats were established by using the improved device with three kinds of impact pressure of 0.1,0.2 and 0.3 MPa,and vital signs and mortality rate were observed.Behavior changes,brain water content and histological changes were observed by Shapira and Wahld method,dry-wet measure and light microscopy at 1st,6th,12th,24th h,and 3rd,7th day after operation respectively.Results The animals subject to impact pressure of 0.1 MPa showed temporary hypopnea with mortality rate of 2.08％,those to 0.2 MPa suffered apnoea of ( 10.88 ± 2.69) s with mortality rate of 4.17％,and those to 0.3 MPa suffered apnoea of (20.60 ± 3.02) s with mortality rate of 16.67％.Wih the impact pressure increased,nervous function score was minimumally decreased to (7.17 ±0.75) in0.1 MPa group,(4.83 ±0.75) in0.2 MPa group and (2.67 ±0.52) in 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 24 h,respectively.The brain injury was involved in the outer layer of cerebral cortex,hippocampal formation and brain stem,and histological observation verified above findings.Conclusion Graded fluid percussion model of brain injury in rats can be produced stabily with the same pathological characteristics as those of human. Key words: Fluid percussion; Brain injury; Model,animal