ACE2 and COVID-19: Researchers have studied the pathogenic mechanism of SARS-CoV-2, the pathogen that causes COVID-19, and have found that the virus mainly exerts its toxic effect by binding to the host receptor membrane ACE2 through its spike S-glycoprotein (Gheblawi et al., 2020), while ACE2 is expressed in a variety of cells in the respiratory tract, so that the SARS-CoV-2 directly infects the bronchial and alveolar epithelial cells, causing lung tissue damage and affecting the ventilation and air exchange function of the body (Sungnak et al., 2020).