Porcine reproductive and respiratory syndrome (PRRS) is a viral infectious disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV) and is devastating the swine industry. MARC-145 cells, an African green monkey kidney cell line, are sensitive to PRRSV-2, and are often used for in vitro studies on PRRSV-2. Preliminary research has shown that glycyrrhizin, an important active component extracted from traditional Chinese medicinal licorice, significantly inhibits the proliferation of PRRSV-2 in MARC-145 cells; however, the in-depth molecular mechanism remains unclear. By determining the cell growth cycle, this study found that PRRSV-2 infection first increased the content of G1-phase MARC-145 cells and then decreased the content of G1-phase cells. Moreover, glycyrrhizin affected the role of PRRSV-2 in regulating the cell cycle. Furthermore, PRRSV-2 had the highest proliferation titer in G0/G1-phase MARC-145 cells, and glycyrrhizin reduced the content of PRRSV-2 in synchronized MARC-145 cells. According to the results of ATPase detection, PRRSV-2 infection weakened the Na+/K+-ATPase and Ca2+/Mg2+-ATPase activities in MARC-145 cells, while glycyrrhizin significantly enhanced their activities in PRRSV-2-infected MARC-145 cells. The above results provide theoretical support toward clarifying the mechanism by which glycyrrhizin inhibits the proliferation of PRRSV-2 in MARC-145 cells. Moreover, these results offer references for the development and use of glycyrrhizin and the clinical treatment of PRRSV-2 infection.
Keywords: ATPase activity; Cell cycle; Glycyrrhizin; MARC-145 cell; Porcine reproductive and respiratory syndrome virus (PRRSV).
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