Figure 4A–4G.

(A-G) Arctigenin efficiently enhanced swimming endurance of sedentary SD rats via increasing AMPK phosphorylation and regulating its downstream antioxidant-related pathways in vivo. (A) SD rats (n=10/group) were supplemented with arctigenin (15 mg/kg) or vehicle via intraperitoneal injection for 6 weeks, and the endurance performance was then measured by a weight-loaded forced swimming test. Exhaustion time was recorded. (B, C) Protein levels of phospho-AMPK, total-AMPK, phospho-p53, total-p53, and Nrf2 were determined by Western blotting in gastrocnemius (B) and quadriceps (C) (n=4/group). (D, E) The levels of ATP were determined in gastrocnemius (D) and quadriceps (E) (n=5/group). (F, G) The expression levels of Cu,Zn-SOD, Txn, Gsr, GPX1, UCP2, p21, PPARα, and PGC-1α from gastrocnemius (F) and quadriceps (G) were measured by qRT-PCR (n=5/group). GAPDH RNA was used as an internal control for calculating mRNA fold changes.