Figure 4

GIN induces endogenous Bdnf expression in primary cultures of rat cortical cells. (a,b) Time-course (a) and dose-dependency (b) of changes in Bdnf mRNA in the presence of GIN in primary cultures of rat cortical cells. (a) Cells were treated with 500 μg/mL GIN and total RNA was prepared at the indicated time. Means ± SEM (n = 3), **p < 0.01, ***p < 0.001, and ****p < 0.0001 vs. water at the same time point (two-way ANOVA with Tukey’s multiple comparisons test). (b) Cells were treated with different concentrations of GIN, and total RNA was prepared 3 h after treatment. Means ± SEM (n = 3), ****p < 0.0001 vs. 0 μg/mL (one-way ANOVA with Dunnett’s multiple comparisons test). (c) Bdnf-Luc cortical cells were seeded into a 96-well culture plate and cultured for 13 days. Cells were then treated with different concentrations of GIN, and luciferase activity in each well was measured 6 h after treatment. Means ± SEM (n = 3), *p < 0.05 and ****p < 0.0001 vs. 0 μg/mL (one-way ANOVA with Dunnett’s multiple comparisons test). (d) Relationship between changes in endogenous Bdnf mRNA expression levels (b) and those in luciferase activity (c) was analysed using a correlation coefficient test. Statistical analysis was performed by Pearson’s correlation coefficient test. (e) The effect of GIN on the expression of 5′ exon-specific Bdnf mRNA in cultured rat cortical cells. Cells were treated with 500 μg/mL GIN and total RNA prepared 3 h after the treatment. Means ± SEM (n = 3), **p < 0.01, ***p < 0.001, and ****p < 0.0001 vs. water (unpaired t-test). N.D.: not detected.