Fig. 1.

TBN protects primary midbrain neurons against MPP⁺-induced toxicity. (A) Chemical structure of TMP, NXY-059, and TBN. (B) TBN has no cytotoxicity on primary midbrain neurons for 24 h incubation at 30–300 μM. Primary midbrain neurons were pre-treated with indicated concentrations of TBN for 2 h followed by treatment with 20 μM MPP⁺ for 24 h (C and D). (C) Effect on cell viability of MPP⁺-treated neurons. (D) Western blot for TH expression in MPP⁺-treated neurons. Data are expressed as mean ± SD of three independent experiments. Data were analyzed using Kruskal-Wallis test followed by Dunn’s multiple comparisons test (B-D). CGNs were pre-treated with 300 μM TBN for 2 h followed by 150 μM MPP⁺ treatment for 24 h. (E, F) Representative graphs and number of apoptotic neurons. Scale bars, 50 µm. Arrows indicate TUNEL-positive cells. Data are expressed as mean ± SD of three random fields. Data were analyzed using one-way ANOVA and Dunnett’s multiple comparisons test (F). ^***P < 0.001 versus untreated control group. ^#P < 0.05, ^##P < 0.01 and ^###P < 0.001 versus MPP⁺ alone group.