Fig 1: Repeated optogenetic stimulation of VTATH terminals in the mPFC ameliorates tumor progression induced by chronic stress in BALB/c nude mice. (A) ~ (B), Schematic illustration of optogenetic manipulation in BALB/c nude mice bearing 4T1 cancer cells. (C), Coronal image co-localization of ChR2-mCherry with TH-expressing neurons in VTA in BALB/c nude mice. Red: ChR2-mCherry, green: TH-positive neurons. Scale bar, 100 µm, insert scale bar 25 µm. (D), Percentage expression of TH and ChR2-mCherry neurons in BALB/C-Nu mice; n = 9 slices from 3 mice. (E), Representative example showing the distribution of ChR2-mCherry-expressing axons in the mPFC of a BALB/c nude mouse. Red: ChR2-mCherry. Scale bar, 100 µm. (F), Tumor volume changes in 4T1 tumor-bearing nude mice with ChR2 or mCherry with UCMS and chronic optogenetic stimulation; n = 9 control, n = 9 S-mCherry, n = 11 S-ChR2, ANOVA, Bonferroni post hoc test. (G) ~ (J), Serum concentrations of VEGF, bFGF, IL-1a, and IL-6; G, H, I, J n = 7 control, n = 7 S-mCherry, H, J n = 7 S-ChR2, G, I n = 6 S-ChR2, ANOVA, Bonferroni post hoc test. *P < .05, **P < .01, ***P < .001