Fig. 1.

Protective effects of heat-killed lactic acid bacteria–conditioned medium (LAB-CM) on cell viability in SH-SY5Y cells experiencing oxidative stress induced by H₂O₂ (50 μM). Cell viability was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. A, Lactobacillus rhamnosus GG; B, Lactobacillus delbrueckii KU200170; C, Lactobacillus plantarum KU200661; D, Lactobacillus lactis KC24. The error bars indicate standard deviations from three independent experiments. The letters on each bar exemplify significant differences (p  < 0.05). open square, 1.0 × 10⁷ CFU/mL; filled square, 1.0 × 10⁸ CFU/mL