ABSTRACT
Aim To investigate the role of mitochondrial translocator protein(TSPO)in the apoptosis of HepG2 cells induced by tanshinone IIA(Tan II A)and the involved mechanism. Methods Following the HepG2 cells treated with Tan ⅡA at 2.5, 5 and 10 μmol·L-1, the cell viability was determined by MTT assay, and intracellular ATP content was determined by luciferin-luciferase method. Oxygen utilization was measured polarographically with a Clark oxygen electrode. Cell apoptosis was determined by Hoechst 33342 staining and flow cytometry. The mitochondrial membrane potential was assessed with JC-1 staining. The intracellular distribution of TSPO was examined by TSPO immunostaining, and the expressions of TSPO, Cyto C, caspase-3, caspase-9 were determined by immunoblotting analysis. Results Tan II A inhibited the proliferation of HepG2 cells in a dose-and time-dependent manner. The treatment with Tan II A inhibited ATP production and oxygen utilization of mitochondria. In addition, Tan ⅡA enhanced TSPO expression and accumulation in nuclei and up-regulated the expression of Cyto C, caspase-3 and caspase-9. Conclusions Tan II A induces the apoptosis of HepG2 cells, which may be related to the TSPO-mediated mitochondrial dysfunction.
