Trauma-Induced Coagulopathy in Rat Models: Assessing Hemostatic Changes in Mild and Severe Traumatic Brain Injuries

Background: Traumatic brain injury (TBI) has been associated with coagulation disorders, and coagulation and fibrinolytic parameters are frequently monitored in the acute stage of TBI. Methods: Using a rat closed head injury model, mild and severe TBIs were induced. Blood samples were obtained at five post-injury time points, including 1 day and 1, 2, 3, and 4 weeks, to assess coagulation and fibrinolytic parameters, specifically prothrombin time (PT), partial thromboplastin time (PTT), D-dimer, and fibrinogen. Results: In mild TBI, all hemostatic parameters remained largely within physiological ranges, despite minor statistical fluctuations in PT and PTT. Conversely, severe TBI resulted in significant elevations of PT (p = 0.00015) and PTT (p = 0.01) during the first week. Additionally, D-dimer levels increased significantly at week 2 (p = 0.024) and week 4 (p = 0.014) post-injury, surpassing the upper limit of normal. Although fibrinogen levels showed a significant increase at week 2 compared to the control group (p = 0.011), they remained within the normal reference range. Conclusions: While mild TBI is characterized by stable hemostatic markers, severe TBI demonstrates a clear and significant progression from acute coagulation activation to secondary fibrinolysis. These findings suggest that severe TBI-induced coagulopathy is a progressive event requiring extended longitudinal monitoring beyond the initial acute phase.