Protein adduct species in muscle and liver of rats following acute ethanol administration.
OBJECTIVE
Previous immunohistochemical studies have shown that the post-translational formation of aldehyde-protein adducts may be an important process in the aetiology of alcohol-induced muscle disease. However, other studies have shown that in a variety of tissues, alcohol induces the formation of various other adduct species, including hybrid acetaldehyde-malondialdehyde-protein adducts and adducts with free radicals themselves, e.g. hydroxyethyl radical (HER)-protein adducts. Furthermore, acetaldehyde-protein adducts may be formed in reducing or non-reducing environments resulting in distinct molecular entities, each with unique features of stability and immunogenicity. Some in vitro studies have also suggested that unreduced adducts may be converted to reduced adducts in situ. Our objective was to test the hypothesis that in muscle a variety of different adduct species are formed after acute alcohol exposure and that unreduced adducts predominate.


METHODS
Rabbit polyclonal antibodies were raised against unreduced and reduced aldehydes and the HER-protein adducts. These were used to assay different adduct species in soleus (type I fibre-predominant) and plantaris (type II fibre-predominant) muscles and liver in four groups of rats administered acutely with either [A] saline (control); [B] cyanamide (an aldehyde dehydrogenase inhibitor); [C] ethanol; [D] cyanamide+ethanol.


RESULTS
Amounts of unreduced acetaldehyde and malondialdehyde adducts were increased in both muscles of alcohol-dosed rats. However there was no increase in the amounts of reduced acetaldehyde adducts, as detected by both the rabbit polyclonal antibody and the RT1.1 mouse monoclonal antibody. Furthermore, there was no detectable increase in malondialdehyde-acetaldehyde and HER-protein adducts. Similar results were obtained in the liver.


CONCLUSIONS
Adducts formed in skeletal muscle and liver of rats exposed acutely to ethanol are mainly unreduced acetaldehyde and malondialdehyde species.
Patel
Vinood B
VB
Department of Biomedical Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK. v.b.patel@westminster.ac.uk
Worrall
Simon
S
Emery
Peter W
PW
Preedy
Victor R
VR
D000079:Acetaldehyde / Q000378:metabolism*; D000435:Alcoholic Intoxication / Q000473:pathology*; D000444:Aldehyde Dehydrogenase / Q000037:antagonists & inhibitors; D000818:Animals; D003484:Cyanamide / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D000431:Ethanol / Q000378:metabolism / Q000633:toxicity*; D008099:Liver / Q000187:drug effects* / Q000473:pathology; D008108:Liver Diseases, Alcoholic / Q000473:pathology*; D008315:Malondialdehyde / Q000378:metabolism*; D018656:Muscle Fibers, Fast-Twitch / Q000187:drug effects / Q000473:pathology; D018657:Muscle Fibers, Slow-Twitch / Q000187:drug effects / Q000473:pathology; D009124:Muscle Proteins / Q000187:drug effects* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology; D009133:Muscular Atrophy / Q000473:pathology*; D010084:Oxidation-Reduction / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D009124:Muscle Proteins; C065424:1-hydroxyethyl radical; D000431:Ethanol; D003484:Cyanamide; D008315:Malondialdehyde; D000444:Aldehyde Dehydrogenase; D000079:Acetaldehyde