Cucurbitacin I Protects H9c2 Cardiomyoblasts against H₂O₂-Induced Oxidative Stress via Protection of Mitochondrial Dysfunction

Figure 3

Cu I suppresses H₂O₂-induced apoptosis in H9c2 cardiomyoblasts. Apoptosis was determined by TUNEL, Hoechst staining, and Western blot analysis of apoptosis-related proteins. Representative images of cells pretreated with 0.1, 0.5, and 1 μM Cu I for 24 h followed by exposure to 500 μM H₂O₂ for additional 24 h in the (a) TUNEL and (c) Hoechst assays. The apoptotic index was calculated by determining the percentage of (b) TUNEL-positive or (d) Hoechst-positive cells. (e) Western blot analysis of Bax, Bcl-2, and cleaved caspase 3 protein expression levels in Cu I-pretreated/H₂O₂-treated cells. (f) The protein expression levels were quantified by scanning densitometry. β-Actin was used as the loading control. Western blot analysis was performed in triplicate with three independent samples. Data are expressed as fold changes ± SEM versus control cells. Significance was analyzed by a one-way ANOVA followed by the Bonferroni post hoc test. and versus control cells. , , and versus H₂O₂ alone-treated cells. Arrows indicate apoptotic cells. Cont: control; Cu I: cucurbitacin I. Scale bar, 100 μm.

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