Fig. 1.

Human Psoas minor muscle is amenable for myofiber culture. a Graphic overview of anatomical dissection of Psoas minor muscle from organ donors. b Photographic overview of myofiber bundle isolation from surgically removed human Psoas minor muscle. Quantification of c single myofibers per bundle and d myofiber bundle diameter, whiskers represent min and max values. e Myofiber viability as quantified by presence of hypercontracted myofibers. f Representative images and quantification of myofiber sarcomere spacing from intact, contracted, and cultured myofibers stained with α-Actinin (green). g Representative image and quantification of human Psoas fiber type stained for type I myofibers (blue), type IIa myofibers (green), type IIx myofibers (red), and wheat germ agglutinin (White). h Quantification of average minimum fiber Feret and i minimum myofiber Feret proportion of myofibers from human Psoas myofibers compared to mouse Extensor digitorum longus and mouse Psoas muscles using SMASH software. j Quantification of human Psoas myofiber length compared to mouse Extensor digitorum longus and mouse Psoas muscles. k Representative image of a single isolated human Psoas minor myofiber stained with DAPI (blue). c, d, f Error bars represent means ± SD, e, g–j Error bars represent means ± SEM; p values are listed. c, d n = 22 myofiber bundles, e n = 4 biological replicates, f n = averages from 12 to 19 myofibers per condition, g n = 5 biological replicates. h–j n = 3 biological replicates