Fig. 5

Effect of Printex 90 on mitochondrial morphology of MSCs during osteogenesis. MSCs exposed to 3 ng/mL and 30 ng/mL Printex 90 were induced to osteogenic differentiation for 1 d, 3 d and 7d. Representative low-magnification (2550×) and high-magnification (20,500×) TEM images showed that although mitochondria structure had few dissolved cristae (black arrow) when exposed to 30 ng/mL CB for 1 d (a), the gradual loss of integrity of the cristae structure and vacuolar degeneration (black arrows) was found when compared to the mitochondria in 0 ng/mL Printex 90 at 3 d (b). Printex 90 had more severe damage to mitochondria showing dissolved mitochondrial cristae (black arrows) in 3 ng/mL CB treated cells and the swelling and abnormal density of mitochondria (black arrows) in 30 ng/mL at 7 d(c). Scale bar = 2 μm (highlight area = 200 nm). N: nucleus; M: mitochondria