Signaling for ethanol-induced apoptosis and repair in vitro

Objectives: To evaluate whether caspases are involved in ethanol (EtOH)-induced apoptosis and if polyenylphosphatidylcholine (PPC) affects apoptosis, in vitro in Hep G2 cells. Methods: Cells were treated with 100 mmol/L EtOH for 24 h and with 2 doses of 100 mmol/L EtOH (1/24 h) in the presence of absence of 20 mmol/L of PPC or 50 μmol/L caspase 3 inhibitor (IDN). Cells were analyzed for apoptosis by transmission electron microscopy (TEM) 6000 cells/treatment, DNA fragmentation by ELISA and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (T dt-mediated d-UTP) nick-end-labeling, TUNEL. Results: 100 mmol/L dose of EtOH resulted in 22 ± 2.5% (p< 0.001) apoptosis (vs. control). Two consecutive doses of 100 mmol/L EtOH for 24 h each caused 36 ± 3.0% (p< 0.001 vs. control and p< 0.05 vs. one dose). PPC significantly reduced apoptosis (vs. non exposed to PPC): 100 mmol/L −12 ± 1.5% (p< 0.05) and 2 × 10−0 mmol/L −20 ± 2.0% (p< 0.001). Pretreatment with 50 μmol caspase inhibitor reduced EtOH-induced apoptosis in a similar proportion. Conclusions: PPC downregulates EtOH-apoptosis by a mechanism similar to caspase inhibition.