SOD2 and diabetes mellitus: The expression of Mn-SOD is reduced in several diabetic animal models, including STZ-induced type 1 diabetes (Spencer et al., 2018; Li et al., 2019), a high-sugar/high-fat or cholesterol diet with STZ-induced diabetes (Onozato et al., 2004; Chen P. et al., 2018; Zayed et al., 2018), Apo E–/– mice with STZ-induced diabetes (Yi et al., 2011), db/db mice (Lu et al., 2013; Hou et al., 2018), BTBR ob/ob mice (Morigi et al., 2020), and diabetic spontaneously hypertensive rats (SHR) (Tang et al., 1997).