DNA fragmentation during exposure of rat cerebella to ethanol under hypoxia imposed in vitro

To gain a better understanding into the mechanisms of damage incurred by ne urons in periods following heavy alcohol exposure during development, we us ed an in vitro system to monitor the effects of alcohol and hypoxia on cell survival and DNA integrity. Samples representing the first few hours of ex posure to alcohol and hypoxia were compared to those resulting from hypoxia alone. Measurements were taken from cell counts using Trypan blue exclusio n and TUNEL assays as web as digital scans of the ethidium bromide fluoresc ence of genomic DNA isolated from the treated tissue. We found that DNA deg radation from hypoxia was accelerated by several hours in the presence of 1 00 mM ethanol, This result depended on age, with adult animals (>8 months) having a similar response to 4-day postnatal animals, while the effect on 1 0-day postnatal animals and those of intermediate age (45 days postnatal) w as increasingly delayed. Different methods of inducing the processive degra dation of DNA produced laddering typical of apoptosis, a biphasic degradati ve process, or patterns usually associated with necrosis. (C) 1999 John Wil ey & Sons, Inc.