Comparative analysis of linear and angular forces in traumatic brain injury: Experimental evidence and mechanistic insights

Head injuries from vehicle collisions, falls, and sports are often the result of complex mechanisms involving both linear and angular forces. This study aims to quantitatively assess the effects of linear and angular force on the severity of traumatic brain injury in rats during collisions. An orthogonal experimental design was employed, facilitating the manipulation of linear velocity, rotational acceleration, and angle (light, medium, heavy) across 54 rats. 24 hours post-injury, magnetic resonance imaging T2-weighted imaging and diffusion tensor imaging were utilized to detect abnormal brain signals, with the fractional anisotropy value of the corpus callosum serving as the primary injury indicator. Anatomical analyses and immunohistological staining were conducted to measure the amyloid precursor protein ( p-APP) accumulation, using integrated optical density as a secondary indicator. Entropy weighting was applied to derive index weights for the injury scoring system. Through analysis guided by analysis of variance and linear regression, it was determined that both linear and angular loadings significantly impacted brain injury severity. Increased rotational acceleration at constant linear velocities correlated with more severe injuries, whereas the rotation angle exhibited minimal effect. Linear velocity emerged as the primary determinant of injury severity, accounting for 91.5 % of the variance, while rotational acceleration and rotation angle contributed 6.5 % and 0.9 %, respectively. These findings offer critical insights for developing protective measures against brain injuries in traffic accidents.