Experimental study on the mechanism of cerebral edema development and MM-MRI manifestation in burned rats

Objective: The goal of this study was to investigate post-burn cerebral edema, establish its MM-MRI manifestation, and explore the underlying molecular mechanisms. Methods: Rats were randomly assigned to four groups (8h, 24h, 48h, and 72h post-burn) and subjected to thermal burns to induce skin injury, following the rat burn model. Treatment was administered based on Parkland's formula. At specific time points, rats were evaluated using MM-MRI sequences (T₁ WI, T2 WI, T₂ FLAIR, DWI, and ADC mapping) alongside histological analysis (H&E, TEM) and molecular techniques (IHC, IF, and WB). Results: All experimental groups exhibited significantly increased post-burn cerebral edema compared to the sham control group. While no significant changes were observed on T₁WI, T₂ WI, and T₂ FLAIR images, post-burn cerebral edema was clearly visible on DWI and ADC maps in the region of interest (ROI) the basal ganglia. Histological analysis (H&E, TEM) corroborated these findings. Notably, all experimental groups (8h, 24h, 48h, and 72h) showed upregulated expression of AQP4 compared to controls, as evidenced by IHC, IF, and WB. Further, astrocyte end-feet and endothelial cells exhibited significant swelling may be due to AQP4 overexpression, leading to increased intracellular water content. Conclusion: This study confirms the presence of post-burn cerebral edema in the early stages following burn trauma, might be mediated by AQP4, as supported by histological findings. Radiological results indicate that DWI and ADC mapping are sensitive methods for diagnosing and monitoring post-burn cerebral edema.