Objective To explore the relationship between the head injury criterion(HIC)values in anterior-posterior(AP)collisions and lateral-medial(LM)collisions.Methods A total of 102 male SD rats were randomly divided into a control group of 0 m(6 rats),4 AP groups(12 rats/group)and 4 LM groups(12 rats/group).After adaptive training,the classical Marmarou model was used to execute the brain AP and LM collisions under a series of different height impacts,and the HIC values were calculated.The experimental group data of the walk-pole test and grip strength test were collected at 24 hours before and after injury,and the data of the proportion of hemorrhage in the corpus callosum and pyramidal tracts were collected at 24 hours after injury.Results As the collision heights increased in both AP and LM groups,there were positive correlations with changes in WP test time and peak GS,and corresponding increases in the proportion of hemorrhage in the cc and py.According to the mathematical relationships between the comprehensive injury degrees and HIC values,it was found that at the same injury degree,LM-HIC value was less than AP-HIC value.A mathematical relationship between AP-HIC and LM-HIC was fitted based on the comprehensive injury degrees.At the same HIC,LM group experienced more severe injuries,and AP group was more tolerant to head collision.Conclusion The injury severity in LM group is greater than that of AP group at the same HIC.Preliminary results show there is a linear mathematical relationship between AP-HIC and LM-HIC.These results can be expected to expand the application scope of HIC and achieve an accurate assessment of the LM collision severity.

Objective To explore the relationship between the head injury criterion(HIC)values in anterior-posterior(AP)collisions and lateral-medial(LM)collisions.Methods A total of 102 male SD rats were randomly divided into a control group of 0 m(6 rats),4 AP groups(12 rats/group)and 4 LM groups(12 rats/group).After adaptive training,the classical Marmarou model was used to execute the brain AP and LM collisions under a series of different height impacts,and the HIC values were calculated.The experimental group data of the walk-pole test and grip strength test were collected at 24 hours before and after injury,and the data of the proportion of hemorrhage in the corpus callosum and pyramidal tracts were collected at 24 hours after injury.Results As the collision heights increased in both AP and LM groups,there were positive correlations with changes in WP test time and peak GS,and corresponding increases in the proportion of hemorrhage in the cc and py.According to the mathematical relationships between the comprehensive injury degrees and HIC values,it was found that at the same injury degree,LM-HIC value was less than AP-HIC value.A mathematical relationship between AP-HIC and LM-HIC was fitted based on the comprehensive injury degrees.At the same HIC,LM group experienced more severe injuries,and AP group was more tolerant to head collision.Conclusion The injury severity in LM group is greater than that of AP group at the same HIC.Preliminary results show there is a linear mathematical relationship between AP-HIC and LM-HIC.These results can be expected to expand the application scope of HIC and achieve an accurate assessment of the LM collision severity.

Objective To investigate the equivalent conversion of head injury criterion(HIC)under anterior-posterior(AP)and lateral-medial(LM)craniocerebral impact for mild craniocerebral injury in rats using motor evoked potential(MEP)and β-amyloid precursor protein(β-APP)immunohistochemistry(IHC).Methods Sixty healthy adult male SD rats were randomly divided into 0 m control group,0.5 m-AP and 0.5 m-LM injury groups,and 1 m-AP and 1 m-LM injury groups(12 rats in each group).The control group did not undergo any impact injury experiment.After the impact injury experiment,the injury and control groups were subjected to excessive anesthesia to produce β-APP immunohistochemical stained slices,and the percentage of positive area and integral optical density(IOD)in the brainstem pyramidal tract area of the slices were determined.The MEP groups were divided in the same manner as the IHC groups and the MEP amplitudes of the MEP and control groups were measured after the impact injury experiment.Results With an increase in the degree of injury,the decrease in MEP amplitude,percentage of positive areas,and IOD in the injury groups significantly increased.When the degree of injury was low,the sensitivity of IHC was higher than that of MEP.When the degree of injury was the same,the HIC in the LM direction was lower than that in the AP direction.When the HIC was the same,the degree of injury in the LM direction was greater than that in the AP direction.Conclusions The joint evaluation of MEP and β-APP can provide experimental references for the study of HIC equivalent conversion in AP-LM craniocerebral impact injury.