Sex Differences in Cerebral Edema after Experimental Traumatic Brain Injury

Abstract

ABSTRACTTraumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. Cerebral edema following TBI is known to play a critical role in injury severity and prognosis. In the current study we used multimodal magnetic resonance imaging (MRI) to assess cerebral edema 24 hours after unilateral contusive TBI in male and female rats. We then directly quantified brain water content in the same subjects ex vivo. We found that in male rats, the injured cortex had higher brain water content and lower apparent diffusion coefficient (ADC) values compared with the contralateral side. Females did not show hemispheric differences for these measures. However, both males and females had similarly elevated T2 values in the injured cortex compared with the contralateral side. A strong correlation was observed between brain water content and T2 values in the injured cortex in male rats, but not in females. These observations raise questions about the interpretation of radiological findings pertinent to edema in female TBI patients. A better mechanistic understanding of sex differences and similarities in the pathophysiology of post-traumatic edema is needed to help improve patient management and the development of effective treatment strategies for TBI in men and women.