FIG. 6.

Rotenone decreases force production and increases engineered muscle fatigue. Myobundles were treated with either vehicle or rotenone (8, 20 nM) for 30 min after 2 weeks of differentiation. (A, B) Twitch and tetanus force production of human myobundles in the presence of 8 and 20 nM rotenone measured after electrical stimulation at 1 Hz and 20 Hz. Results represent mean ± SEM of four separate donors. (C, D) Representative traces and averaged data of relative changes in tetanus force production during a 30-s 20 Hz stimulation of myobundles with and without rotenone. *p < 0.05, **p < 0.01. (E) Correlation between bioenergetic health index (BHI) and percent relative force after 30 s of electrical stimulation at 20 Hz. Corresponding rotenone concentrations are adjacent to each point and the 95% confidence intervals for the linear regression line are shaded in gray. Results represent mean ± SEM of four separate donors.