Fig. 7

Degrees of microglial activation negatively correlate with the survival of DA neurons in the SN during aging and in vitro. a Representative immunohistochemical images show TH⁺ cells in the SN and DAT⁺ signal in the striatum of 3-, 6-, and 12-month-old mice. Quantitative results of numbers of TH⁺ cells and intensities of DAT⁺ signal (n = 8 in each age group) are shown on the right panels. To control for non-specific binding, TH and DAT antibodies were replaced by their respective isotype antibodies. b Representative confocal micrographs show the Iba1⁺ and TH⁺ cells in the SN of 6- and 12-month-old mice. Correlations (Pearson) between numbers of TH⁺ cells and areas and numbers of Iba1⁺ cells are shown on the right panels (n = 24). c Viability of TH⁺ cells cultured for 24 h in conditioned media of BV2 cells (n = 4). The experimental timeline is shown on the left panel, while the cell survival rate is shown on the right panel. *p < 0.05, ***p < 0.001 versus BDNF(-)LPS(-) group; ^###p < 0.001 versus BDNF(-)LPS(+) group. d Viability of TH⁺ cells cultured for 24 h in conditioned media of primary microglia (n = 4). The experimental timeline is shown on the left panel, while the cell survival rate is shown on the right panel. ***p < 0.001 versus respective Saline group; ^#p < 0.05 versus respective Veh group (n = 4). e Viability of TH⁺ cells cultured for 24 h in conditioned media of virus-infected BV2 cells (n = 4). The experimental timeline is shown on the left panel, while the cell survival rate is shown on the right panel. Bonferroni post-hoc test: ^$$p < 0.01: shTrkB versus respective shLacZ group. *p < 0.05, ***p < 0.001: LPS(+) versus respective LPS(-) group; ^#p < 0.05: BDNF(+) versus respective BDNF(-) group. Data are presented as mean ± S.D.