Study of acetylcholinesterase activity and apoptosis in SH-SY5Y cells and mice exposed to ethanol

Ethanol is one of the most commonly abused psychotropic substances with deleterious effects on the central nervous system. Ethanol exposure during development results in the loss of neurons in brain regions and when exposed to ethanol cultured cells undergo apoptosis. To date no information is available on whether abnormally high AChE activity is characteristic of apoptosis in animals exposed to ethanol. The aims of the present study were to determine whether induction of AChE activity is associated with ethanol-induced apoptosis and to explore the mechanism of enhanced AChE activity induced by ethanol. For this purpose, in vitro and in vivo experiments were performed. AChE activity was quantified by spectrophotometry and apoptosis by flow cytometer in SH-SY5Y cells exposed to ethanol. The results showed that cells treated with 500 mM ethanol for 24 h had a 9-fold increase in apoptotic cells and a 6-fold increase in AChE activity compared with controls. Mice exposed acutely to 200 mu l of 20% ethanol daily on days 1-4 had elevated AChE activity in plasma on days 3-7. On day 4, plasma AChE activity was 2.4-fold higher than pretreatment activity. More apoptotic cells were found in the brains of treated mice compared to controls. Cells in brain sections that were positive in the TUNEL assay stained for AChE activity. In conclusion, AChE activity and apoptosis were induced in SH-SY5Y cells and mice treated with ethanol, which may indicate that increased AChE may related to apoptosis induced by ethanol. Unusually high AChE activity may be an effect marker of exposure to ethanol. The relationship between AChE and apoptosis might represent a novel mechanism of ethanol-associated neuronal injury.