Fig. 7: Alleviation of oxidative damage by H₂O₂ or MPP⁺ in lysosome-upregulated conditions.

A Microscopic images (upper) and a quantitative graph (lower) show PI-stained damaged neuronal cells after exposure to H₂O₂ (140 µM, 5 h) or MPP⁺ (300 µM, 24 h) with or without TPEN (1 µM) in mouse cerebrocortical cultures. Scale bar: 200 µm. The bar graph indicates the fluorescence intensity of PI measured using the Image J program (mean ± SEM, n = 8 or 6 different fields taken from ≥4 independent biological replicate experiments, ^####p < 0.0001 for control, **p < 0.01 for H₂O₂, and *p < 0.05 for MPP⁺, analyzed using ANOVA with Dunnett’s post-hoc test). B Bars indicate LDH release from damaged neuronal cells after exposure to H₂O₂ (140 µM, 5 h) or MPP⁺ (300 µM, 24 h) with or without TPEN (1 µM) in mouse cerebrocortical cultures (mean ± SEM, n = 6 or 4 taken from ≥4 independent biological replicate experiments, ***p < 0.001; two-tailed Student’s t-test). C Microscopic images (upper) and a quantitative graph (lower) show PI-stained damaged neuronal cells after exposure to H₂O₂ (140 µM, 5 h) or MPP⁺ (300 µM, 24 h) with or without EGF (100 ng/ml) in mouse cerebrocortical cultures. Scale bar: 200 µm. The bar graph indicates the fluorescence intensity of PI (mean ± SEM, n = 6 or 4 different fields taken from ≥4 independent biological replicate experiments, ^####p < 0.0001 for control, and *p < 0.05 for H₂O₂ or MPP⁺, analyzed using ANOVA with Dunnett’s post-hoc test). D Bars indicate LDH release from damaged neuronal cells after exposure to H₂O₂ (140 µM, 5 h) or MPP⁺ (300 µM, 24 h) with or without EGF (100 ng/ml) in mouse cerebrocortical cultures (mean ± SEM, n = 12 or 4 taken from ≥4 independent biological replicate experiments, **p < 0.01 or ****p < 0.0001; two-tailed Student’s t-test). E Microscopic images (upper) and a quantitative graph (lower) showing PI-stained damaged neuronal cells after exposure to H₂O₂ (140 µM, 5 h) or MPP⁺ (300 µM, 24 h) in empty vector (NC) or LAMP-1 overexpressing neuronal cells. Scale bar: 50 µm. The bar graph indicates the ratio of PI-positive cells compared to Hoechst counterstained cells, measured using the Image J program (mean ± SEM, n = 5–6 different fields taken from 3 independent biological replicate experiments, *p < 0.05 for H₂O₂ and **p < 0.01 for MPP⁺, analyzed using two-tailed Student’s t-test). F Bar graph showing LDH release after exposure to H₂O₂ (140 µM, 5 h) or MPP⁺ (300 µM, 24 h) in empty vector (NC) or LAMP-1 overexpressing neuronal cells (mean ± SEM, n = 4–6 taken from ≥3 independent biological replicate experiments, *p < 0.05 for H₂O₂ and **p < 0.01 for MPP⁺, analyzed using two-tailed Student’s t-test). G Bars indicate LDH release from damaged HEK cells at 12 h after exposure to H₂O₂ (280 µM) in empty vector (NC) or LAMP-1 overexpressing HEK cells (mean ± SEM, n = 4, **p < 0.01; two-tailed Student’s t-test). H Bars indicate cell viability measured using CCK-8 viability assay at 50 h after exposure to MPP⁺ (3 mM) in empty vector (NC) or LAMP-1 overexpressing HEK cells (mean ± SEM, n = 9, ***p < 0.001; two-tailed Student’s t-test).