Leukocyte Platelet-Rich Plasma-Derived Exosomes Restrained Macrophages Viability and Induced Apoptosis, NO Generation, and M1 Polarization.

BACKGROUND: Chronic refractory wounds refer to wounds that cannot be repaired timely. Platelet-rich plasma (PRP) has significant potential in chronic wound healing therapy. The exosomes isolated from PRP were proved to exhibit more effectiveness than PRP. However, the therapeutic potential of exosomes from PRP on chronic refractory wounds remained elusive. Hence, this study aimed to clarify the action of exosomes from PRP on chronic refractory wounds by evaluating the response of macrophages to exosomes. METHODS: Pure platelet-rich plasma (P-PRP) and leukocyte platelet-rich plasma (L-PRP) were prepared from the fasting venous blood of healthy volunteers. Exosomes were extracted from P-PRP and L-PRP using ultracentrifugation and identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blot. Macrophages were obtained by inducing THP-1 cells with phorbol-12-myristate-13 acetate (PMA). The internalization of exosomes into macrophages was observed utilizing confocal laser scanning microscopy after being labeled with PKH67. Cell viability was determined by CCK-8 assay. Cell apoptosis was measured utilizing a flow cytometer. The polarization status of M1 and M2 macrophages were evaluated by detecting their markers. Nitric oxide (NO) detection was conducted using the commercial kit. RESULTS: Exosomes from P-PRP and L-PRP were absorbed by macrophages. Exosomes from L-PRP restrained viability and induced apoptosis of macrophages. Besides, exosomes from P-PRP promoted M2 polarization, and exosomes from L-PRP promoted M1 polarization. Furthermore, exosomes from L-PRP promoted NO generation of macrophages. CONCLUSION: Exosomes from L-PRP restrained viability, induced apoptosis and NO generation of macrophages, and promoted M1 polarization, while exosomes from P-PRP increased M2 polarization. The exosomes from L-PRP presented a more effective effect on macrophages than that from P-PRP, making it a promising strategy for chronic refractory wound management.