ABSTRACT
ObjectiveTo explore the mechanisms of Astragali Radix-Curcumae Rhizoma （HQ-EZ） in alleviating hypercoagulability and inhibiting tumor growth and metastasis by modulating the formation of neutrophil extracellular traps （NETs） via the complement component 5a （C5a）/C5a receptor （C5aR） pathway. MethodForty male C57BL/6 mice were randomized into four groups： Blank， model， HQ-EZ （8.2 g·kg-1）， and PMX53 （1 mg·kg-1）. The mouse model of Lewis lung cancer was established in other three groups except the blank group. Mice were administrated with corresponding drugs from day 3 after modeling. Specifically， the HQ-EZ decoction was administrated for 14 consecutive days， while intraperitoneal injection of PMX53 was implemented on days 3， 6， 9， 12， and 15. Mouse body weight and tumor diameter were measured every two days. On the next day of the last administration， lung microCT was performed to observe the tumor metastasis in vivo. Blood samples were collected from the eyeball after anesthetization， and tumor and lungs were collected after the mice were sacrificed. Tumor weight was measured to calculate the tumor growth inhibitory rate. Enzyme-linked immunosorbent assay was employed to measure the levels of C5a， neutrophil elastase （NE）， citrullinated histone-H3 （Cit-H3）， myeloperoxidase （MPO）， matrix metallopeptidase-9 （MMP-9）， NETs， von Willebrand Factor （vWF）， tissue factor （TF）， and P-selectin in the serum and tumor tissue. Terminal-deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling was conducted to assess apoptosis in the tumor tissue. Hematoxylin-eosin staining was conducted to observe lung metastasis， and immunofluorescence （IF） was employed to observe the expression of NETs in the tumor tissue. Western blot was employed to determine the protein levels of C5aR， MPO， and Cit-H3 in the tumor tissue. ResultCompared with the blank group， the model group had nodules in the lung， increased areas with low X-ray transmittance， appearance of nodular foci and multiple hemorrhagic foci in the lungs， and darkening lung color. Furthermore， the modeling elevated the serum levels of C5a， NETs and related proteins， vWF， TF， and P-selectin （P<0.01）. Compared with the model group， HQ-EZ and PMX53 reduced the lung metastases， areas with low X-ray transmittance， and nodules in the lungs and lightened the lung color. Compared with the model group， the two drug intervention groups showed flat tumor growth curves， decreased tumor weight （P<0.01）， increased apoptosis of tumor cells （P<0.01）， lowered levels of C5a， NETs and related proteins， vWF， TF， and P-selectin both in the serum and tumor tissue （P<0.05）， and down-regulated protein levels of C5aR， MPO， and Cit-H3 （P<0.05）. ConclusionHQ-EZ inhibited the expression of NETs by suppressing the C5a/C5aR pathway， thereby alleviating hypercoagulability and inhibiting tumor growth and metastasis.