Objective: To explore the relationship between NB4 cell apoptosis induced by tanshinone IIA (TanIIA) and the cell mitochondrial transmembrane potential (DeltaPsim).
Methods: NB4 cells were treated with TanIIA, As(2)O(3), TanIIA plus 1.0 micro g/ml CsA and As(2)O(3) plus 1.0 micro g/ml CsA, respectively. Morphological changes were observed under light microscope and transmission electron microscope. The percentages of sub-G(1) cells and DeltaPsim of cells doublely stained with PI and Rh123 were assayed by flow cytometry.
Results: The percentages of sub-G(1) cells after treatment with 1.0 micro g/ml and 2.0 micro g/ml TanIIA had no significant difference but was higher than that of 0.5 micro g/ml. After treatment with TanIIA, NB4 cells appeared the classical apoptotic morphology. The percentages of sub-G(1) cells were increased, while the DeltaPsim reduced (P < 0.01) and there was a linear correlation between them. The increment of sub-G(1) cell percentages and decrement of DeltaPsim induced by TanIIA were partly inhibited by CsA (P < 0.01).
Conclusions: TanIIA can induce NB4 cells apoptosis through opening the mitochondrial permeability transition pore and reducing DeltaPSgr;m, and this effect could be inhibited by CsA.