Reactive oxygen species (ROS) content was determined using the 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) method (Guo et al., 2015). 2′,7′-dichlorofluorescein is the product of reaction of ROS and DCFH-DA, which can be detected by a fluorescence spectrophotometer (RF-5301PC, Shimadzu, Japan). MDA content was determined according to Han et al. (2014) by evaluating thiobarbituric acid chromogenic reaction. The UV absorbance were read at 532 nm. DNA oxidative damage indicator (8-OHdG) was determined using enzyme linked immunosorbent assay kit (Shanghai Hengyuan Biological Technology Co., Ltd, China). The samples were read at 450 nm by microplate reader (MK3, Thermo Fisher, USA).
