Kynurenine, a Tryptophan Metabolite That Increases with Age, Induces Muscle Atrophy and Lipid Peroxidation

Figure 4

Effects of KYN with inhibition of Ahr in vitro and global knockout of Ahr in vivo. (a) Treatment of myoblasts with KYN and the small-molecule Ahr inhibitor CH-223191 simultaneously increased H₂O₂ significantly compared to KYN alone (/group). (b) H₂O₂ from quadriceps of Ahr-knockout mice treated with KYN was increased slightly but not significantly compared to that from VEH. (c) KYN treatment of Ahr-knockout mice significantly decreased quadriceps mass. (d) Fiber size of quadriceps muscles from Ahr-knockout mice decreased slightly but not significantly with KYN treatment. (e) 4HNE staining of quadriceps muscles increased slightly but not significantly with KYN treatment. Data are presented as . , , and . (b–d) Pooled male and female: .

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