Establishment of a Modified Ferric Chloride-Induced Canine Superficial Femoral Artery Thrombosis Model

Ferric chloride (FeCl₃) is a common agent for inducing thrombosis in laboratory animals. However, there is no sufficient data regarding the conditions of model preparation in dogs. We aimed to identify the optimal concentration and solvent of FeCl₃ for inducing canine superficial femoral artery thrombosis. We applied 30, 40, or 50% FeCl₃ in 1 M hydrochloric acid or water topically on the superficial femoral artery for 30 min to induce thrombosis, respectively, with the distal end of the exposed artery clipped for 15 min. Then the thrombus size and blood flow were assessed by the High-Resolution Ultrasonic Photoacoustic Multimode Imaging System, and pathological changes were evaluated with HE staining. Regardless of the concentration or solvent, FeCl₃ solutions successfully induced stable and dense thrombi. At day 28, 30% FeCl₃ in 1 M HCl demonstrated greater peak systolic velocity (PSV) ratios of normal and recanalization rates than 40% FeCl₃ in 1 M HCl. Except for day 14, 40% FeCl₃ in H₂O had lower PSV ratios and recanalization rates compared to 50% FeCl₃ in H₂O. The 40% FeCl₃ in H₂O demonstrated greater blood flow recovery than the 40% FeCl₃ in 1 M HCl. Compared to the water solution, the acidic solution caused more pronounced endothelial cell damage, with no differences between varying concentrations in the same solvent. FeCl₃ application combined with blood flow blockage effectively induced stable thrombi in the superficial femoral arteries of dogs. Hydrochloric acid solutions demonstrated better thrombus formation efficacy than water.