Figure 4: Effect of tanshinone IIA on the protein levels of Bax, Bcl-2, and cleaved caspase-3 in glutamate-exposed SH-SY5Y cells. The cells were treated with tanshinone IIA at the indicated concentrations and then exposed to 10 mM glutamate. Western blot analysis was performed using antibodies against Bax (a), Bcl-2 (b), and cleaved caspase-3 (c), and β-actin was used as a loading control. Relative protein levels were quantified by densitometry and normalized to β-actin. The data are presented as mean ± SEM of three independent experiments. Tan IIA: tanshinone IIA; Glu: glutamate. compared to the cells exposed to glutamate alone.