Fig. 6

(a) In vivo histological results of fluorescent microscopy showing the expression of P-selectin in vessels. (b) In vivo results of light microscopy showing vascular H&E histological changes (scale bar: 50 μm), thrombus treatment, and prevention of thrombus regeneration in animals treated with different formulations. The antithrombotic efficacy was analyzed using the following method: (histologically microscopic vascular clot area/lumen area) × 100%. The calculated areas or microscopic fluorescence intensities were analyzed using ImageJ software. (c) Schematic illustration depicting the tail bleeding test. (d) For the tail bleeding test, after administration and treatment with dipyridamole (DIP)-fucoidan (FU)-polypyrrole (PPy) nanoparticles (NPs) or the same amount of DIP (moderate dose (MD), 3 mg/kg body weight), the distal 1-cm section of a mouse tail was cut off using a scalpel and submerged in PBS prewarmed to 37 °C. Animals were observed for 30 min. To calculate the bleeding quantity, the bleeding extent was assessed based on the hemoglobin level in the PBS solution by determining the absorbance spectra of hemoglobin. (e) For another bleeding test, filter paper was used to absorb blood from the bleeding liver of test animals. Blood-diffused areas on the filter paper were measured using ImageJ software. Microscopic and biochemical data confirmed that the DIP-FU-PPy NPs possessed antithrombotic efficacy and avoided clot reformation and bleeding risk in vivo. Experimental results are presented as the mean ± SD (n = 6). (* p < 0.05; NS (non-significant) p > 0.05)