24-Epibrassinolide, a Phytosterol from the Brassinosteroid Family, Protects Dopaminergic Cells against MPP⁺-Induced Oxidative Stress and Apoptosis

Figure 5

Time course changes in antioxidant enzyme activities in neuronal PC12 cells. (a) SOD activity: administration of 24-Epi alone (□) induced higher SOD activity than MPP⁺ (∆). Preincubation with 24-Epi prior to MPP⁺ (▲) also augmented SOD activity. A maximal increase was apparent after 3 h of treatment. (b) CAT activity: MPP⁺ (∆) induced a constant elevation of CAT activity until 24 h. 24-Epi (□) heightened CAT activity after 3 h of incubation with a subsequent decline in CAT activity becoming less active than the control after 24-h exposure. Pretreatment with 24-Epi before MPP⁺ (▲) increased CAT activity similarly to that observed in cells treated with 24-Epi alone. (c) GPx activity: pretreatment with 24-Epi (□) induced a maximal increment of GPx activity at 24 h while the increase with MPP⁺ (∆) and 24-Epi + MPP+ (▲) was less pronounced. Data are expressed as means ± S.E.M. 𝑛=3. ^∗𝑃<.05, ^∗∗𝑃<.01, and ^∗∗∗𝑃<.001 versus Ctrl; ^•𝑃<.05, ^••𝑃<.01, and ^•••𝑃<.001 versus MPP⁺.

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