Objective   To investigate cell apoptosis in mtDNA-depleted SK-Hep1 cells and the transmitochondrial cybrids on the basis of establishment of ρ

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SK-Hep1 (a mtDNA-depleted cell line derived from human hepatoma cell line SK-Hep1) and the transmitochondrial cybrids

SK-Hep1Cyb.    Methods   SK-Hep1 cells

ρ

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SK-Hep1 cells

and the transmitochondrial cybrids were cultured in high-glucose DMEM. Apoptosis was determined by Annexin V/PI assay. Flow cytometry (FCM) and laser scan confocal microscopy were used to detect reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) respectively. Western blot analysis was applied to detect Bcl-2 and Bax expressions in the above 3 groups of cells. Distribution of Bcl-2 in the 3 groups was assessed by immunofluorescence analysis.    Results   Apoptotic ratio of SK-Hep1

ρ

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SK-Hep1 and SK-Hep1Cyb cells were (2.01±0.11)%

(0.37±0.08)% and (2.10±0.12)％

respectively. ρ

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SK-Hep1 cells were more counteractive against apoptosis than the other 2 cells (P0.05). Fluorescence intensity of ROS in ρ

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SK-Hep1 cells was significantly higher than that of the parent cells (35.5 vs 15.6

P0.01)

but the ΔΨm was comparatively lower (55.0 vs 65.9

P0.05)

meanwhile the ratio of Bcl-2/Bax was elevated. After transmitochondria to ρ

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SK-Hep1 cells

the SK-Hep1Cyb cells had all the above reversed.    Conclusion   mtDNA-depleted cells are more counteractive against apoptosis

and it might be related to the elevated mitochondrial Bcl-2/Bax and ROS.