Effects of α-linolenic acid (ALA) and essential amino acids (EAAs) on C2C12 cell proliferation. The control growth medium (GM) contained 0.5% EAA. (A) Schematic diagram of the proliferation experiment. (B) Images of morphological changes were obtained using phase contrast photomicrography after 48 h of treatment. Scale bars represent 100 μm. (C) Cell viability of C2C12 cells was measured using the cell counting kit (CCK)-8 assay. Cells were treated with ALA (0, 5, 10, and 25 μM) or EAA (1 and 2%) for 48 h. (D, E) Expression levels of proliferating cell nuclear antigen (PCNA) were determined using western blotting and immunofluorescence assays. Scale bars represent 20 μm. (F) mRNA expression levels of PCNA and Ki-67 were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). *p < 0.05, **p < 0.01, ***p < 0.005 vs. the control group.