ARG1 and major depressive disorder: EE can induce anti-inflammatory M2 polarization of microglia through selective expression of Arginase1 gene (Arg-1) in the hippocampus [106], and this case also supports that EE can alleviate and change the depression-like behavior of depression model rats by regulating microglia phenotype, inhibiting proinflammatory factors and promoting anti-inflammatory factors [107].