Early loss of large genomic DNA in vivo with accumulation of Ca2+ in the nucleus during acetaminophen-induced liver injury.
Hepatotoxic doses of acetaminophen cause early impairment of Ca2+ homeostasis in the liver. This in vivo study considers the nucleus as a possible site of lethal Ca2+ action by evaluating whether acetaminophen raises Ca2+ in this compartment, whether DNA becomes altered, and whether DNA changes occur early enough during injury to contribute causally to necrosis. Fed Swiss mice were treated with 600 mg/kg acetaminophen ip and livers and blood samples were collected over time. Total nuclear Ca2+ accumulation and fragmentation damage to DNA showed modest parallel increases between 2 and 6 hr, followed by greater than 200% rises at 12 hr mirroring the appearance of frank liver injury (ALT greater than 10,000 U/liter). However, agarose gel electrophoresis revealed extensive loss of large genomic DNA from 2 hr onward, accompanied by the appearance of periodic DNA fragments. Thus, acetaminophen raised nuclear Ca2+ concentrations and promoted DNA fragmentation in vivo. The considerable cleavage of DNA seen at late times probably resulted from cell death, whereas loss of large genomic DNA from 2 hr onward appeared at an early enough point in time to be a contributing factor in acetaminophen-induced liver necrosis.
Ray
S D
SD
College of Pharmacy, University of New Mexico, Albuquerque 87131.
Sorge
C L
CL
Raucy
J L
JL
Corcoran
G B
GB
D000082:Acetaminophen / Q000633:toxicity*; D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D056486:Chemical and Drug Induced Liver Injury; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D004586:Electrophoresis; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008107:Liver Diseases / Q000378:metabolism; D051379:Mice; D009336:Necrosis
D000082:Acetaminophen; D004247:DNA; D000410:Alanine Transaminase; D002118:Calcium