Exploratory Analysis of Thromboinflammatory and Hematological Changes Following Electrolytic Femoral Vein Injury in Wistar Rats

Introduction Animal models provide controlled experimental settings for investigating thromboinflammatory processes and evaluating potential biomarkers. The aim of this study was to explore the hematological and inflammatory responses following an adapted electrolytic femoral vein injury protocol in laboratory rats. Particular emphasis was placed on identifying potential associations between blood parameters and histopathologically detected venous thrombosis, as well as comparison of two different anticoagulant regimens. Methods Twenty-four female Wistar rats (approximately 15 months old; age varied slightly in weeks between sequentially allocated groups) were allocated to a sham control group (n = 4), an untreated electrolytic injury control group (n = 4), and an electrolytic injury group treated with either enoxaparin or rivaroxaban (n = 8 each). Blood samples were collected at baseline (T0), one day (T1), and seven days (T7) post-intervention. Complete blood count (CBC) parameters, CBC-derived indices (granulocyte-to-lymphocyte ratio (GLR), platelet-to-lymphocyte ratio (PLR)), and plasma myeloperoxidase (MPO) levels were determined. Following euthanasia on day one (untreated group) or day seven (sham and treated groups), thrombus presence was assessed histopathologically. Results Seven days post-intervention, the leukocyte, granulocyte, and lymphocyte counts decreased, while the PLR increased significantly in all study groups. MPO increased significantly at T7 compared to baseline in the rivaroxaban group, while no significant changes were observed in the enoxaparin group. No significant between-treatment differences were observed in GLR, PLR, or MPO levels. Histopathological analysis confirmed thrombi occurrence in 6/20 animals (1/4 untreated and 5/16 treated). Exploratory ROC analysis suggested discriminatory potential of MPO, but not GLR or PLR, for histopathologically detected thrombus. Conclusion The adapted electrolytic femoral vein injury model was associated with dynamic changes in hematological and inflammatory parameters. MPO showed potential as a thromboinflammatory biomarker. However, given the limited detection of thrombus, these findings require validation in larger studies, using a more reliable thrombosis induction protocol.