Fig. 2.
Effect of menadione on IGF-1 signaling in human femur and talar chondrocytes. Confluent human articular chondrocytes isolated from the femur and talus of the same donor were treated for 30 min with IGF-1 (50 ng/ml) or pre-treated with menadione (25 μM) for 30 min prior to IGF-1 treatment (30 min). (A) Representative immunoblots from n = 6 independent donors showing the phosphorylation of Akt and its downstream marker of activation, PRAS40. (B-C) Densitometric analysis showing phosphorylation of Akt and pPRAS40. Phosphorylated bands were normalized to total protein as loading controls and presented as mean values ± 95% CI (n = 6).