In Utero Ethanol Exposure Elicits Oxidative Stress in the Rat Fetus

Abstract

Prior studies in our laboratory have shown that exposure of cultured fetal rat hepatocytes to ethanol (E) blocks epidermal growth factor-dependent replication and that this is paralleled by cell membrane damage, mitochondrial dysfunction, membrane lipid peroxidation (LP), and enhanced generation of reactive oxygen species. These measures of E-mediated oxidative stress (OS) were mitigated by treatment with antioxidants, and cell replication could be normalized by maintaining cell glutathione (GSH) pools. We have now extended these studies to an in vivo model. Rats were administered E (4 g/kg, po) at 12-hr intervals on days 17 and 18 of gestation and killed on day 19, 1 hr following a final dose of E (a total of 5 doses). Fetal and maternal brain and liver were assayed for signs of OS. The 2-day in utero E exposure increased membrane LP in fetal brain as evidenced by increased malondialdehyde (MDA) levels from 1.76 +/- 0.12 SE (nMol/mg protein) to 2.00 +/- 0.08 (p < 0.05) and conjugated dienes from 0.230 +/- 0.006 SE (OD223/mg lipid) to 0.282 +/- 0.006 (p < 0.05). In fetal liver, MDA levels increased from 2.39 +/- 0.08 SE (nMol/mg protein) to 2.87 +/- 0.08 (p < 0.05), whereas dienes differed significantly only between ad libitum controls and the E and pair-fed control groups (p < 0.05). E decreased GSH levels in fetal brain by 19%, from 19.88 +/- 0.72 to 16.13 +/- 1.06 (nMol/mg protein) (p < 0.05). A 10% decrease in GSH was seen in fetal liver (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Ethanol exposure of neonatal rats does not increase biomarkers of oxidative stress in isolated cerebellar granule neurons

“…This was notable based on previous work of other investigators and current hypotheses (Heaton et al, 2000a;Heaton et al, 2003;Heaton et al, 2002;Henderson et al, 1995;Ramachandran et al, 2003;Siler-Marsiglio et al, 2004;Siler-Marsiglio et al, 2005b). However, it is consistent with reports from several investigators suggesting that oxidative stress is not involved in ethanol neurotoxicity (Edwards et al, 2002;Grisel and Chen, 2005;Pierce et al, 2006;Smith et al, 2005;Tran et al, 2005).…”

“…Based on multiple reports, it has been hypothesized that ethanol induces production of ROS and, further, that antioxidants protect neurons from ethanol-induced death by blocking production of ROS (Heaton et al, 2000a;Heaton et al, 2003;Heaton et al, 2002;Henderson et al, 1995;Ramachandran et al, 2003;Siler-Marsiglio et al, 2004;Siler-Marsiglio et al, 2005b). However, other studies have failed to support the hypothesis (Edwards et al, 2002;Grisel and Chen, 2005;Pierce et al, 2006;Smith et al, 2005;Tran et al, 2005).…”

“…These include: altered neuronal metabolism (de la Monte et al, 2005;Li et al, 2002), glutamate excitotoxicity (Ikonomidou et al, 2000), disruption of apoptotic regulators (Heaton et al, 2006;Siler-Marsiglio et al, 2005a), limited neurotrophin support (Heaton et al, 2000b;Light et al, 2002b;Light et al, 2001), restricted synaptic development (Klintsova et al, 2002;West et al, 1994), and oxidative stress (Heaton et al, 2003;Heaton et al, 2002;Henderson et al, 1995;Ramachandran et al, 2003;Reyes et al, 1993;Siler-Marsiglio et al, 2005b;Smith et al, 2005). Oxidative stress can cause mitochondrial membrane depolarization, which is followed by cytochrome c release, caspase activation, and apoptosis (Bernardi et al, 2006;O'Rourke et al, 2005).…”

“…Oxidative stress can cause mitochondrial membrane depolarization, which is followed by cytochrome c release, caspase activation, and apoptosis (Bernardi et al, 2006;O'Rourke et al, 2005). In fact, ethanol treatment in cell culture as well as in the developing brain in vivo increases levels of ROS and free radicals, decreases endogenous antioxidant enzyme and metabolite concentrations, and produces lipid peroxidation (Heaton et al, 2003;Heaton et al, 2002;Henderson et al, 1995;Ramachandran et al, 2003;Siler-Marsiglio et al, 2005a;Siler-Marsiglio et al, 2004;SilerMarsiglio et al, 2005b;Smith et al, 2005).…”

Intrauterine ethanol exposure results in hypothalamic oxidative stress and neuroendocrine alterations in adult rat offspring

“…It has been suggested that chronic EtOH feeding reduces the entry of cytosolic GSH into mitochondria and that the decreased mitochondrial pool size of GSH results in reduced GPx activity (25). Perinatal EtOH is known to increase systemic oxidative stress in developing organs, particularly the liver and the brain (18,32,33,41,55). There have been reports of EtOH-associated oxidative stress in the hippocampus and other brain regions where postnatal EtOH decreased GSH content and increased lipid peroxides and protein carbonyls with brain region and age-dependent differences in EtOH sensitivity and the response of antioxidant enzymes (29,32,33,41,55).…”