ABSTRACT
We have studied the effects of hydrogen peroxide (H2O2) on the differentiation and maintenance of C2C12 myoblasts. The effects of H2O2 were evaluated by cell viability, total protein concentration, the relative amount of muscle-related proteins, sarcomere structure, and active tension generation. Oxidative stress is one of the major causes of myopathy after exercise and thus establishing the method to evaluate the effects on muscle function is essential. The primary function of striated muscle is to generate force, thus, the measurement of active tension is important in assessing the effect of chemicals on muscle. Among the indices we tested, the sarcomere structure was the most sensitive to the H2O2 exposure while the cell viability was less sensitive. The effects of H2O2 on active tension correlated with a decrease in the amount of muscle proteins. In this study, our results showed that the effect of chemicals on muscle should be measured in multiple ways, including active tension generation, for a better understanding of its physiological impact.
Subject(s)
Cell Differentiation/drug effects , Hydrogen Peroxide/pharmacology , Muscle, Skeletal/cytology , Animals , Cell Line , Cell Survival/drug effects , Dose-Response Relationship, Drug , Mice , Muscle, Skeletal/metabolism , Myoblasts/cytology , Myoblasts/drug effects , Oxidative Stress/drug effectsABSTRACT
Single-walled carbon nanotubes (SWCNTs) are reported to spontaneously align in a rotational pattern by drying a liquid droplet of toluene containing polyfluorene as a dispersant. By situating a droplet of an SWCNT solution around a glass bead, spiral patterns are generated. The parallel alignment of SWCNTs along one stripe of such a pattern is confirmed using scanning electron microscopy and polarized optical microscopy. The orientation order increases toward the outer edge of a stripe. The stripe width in the pattern is proportional to the solute concentration, and the width and position of the stripes follow geometric sequences. The growth of the rotational pattern is also observed in real time. The process of spiral pattern formation is visualized, indicating the role of the annihilation of counter-traveling accompanied by continuous depinning. The geometric sequences for the stripe width and position are explained by the near-constant traveling speed and solute enrichment at the droplet periphery.
