INCREASES OF INTRACELLULAR MAGNESIUM PROMOTE GLYCODEOXYCHOLATE-INDUCED APOPTOSIS IN RAT HEPATOCYTES

Citation
T. Patel et al., INCREASES OF INTRACELLULAR MAGNESIUM PROMOTE GLYCODEOXYCHOLATE-INDUCED APOPTOSIS IN RAT HEPATOCYTES, The Journal of clinical investigation, 94(6), 1994, pp. 2183-2192
Citations number
63
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Medicine, Research & Experimental
ISSN journal
0021-9738
Volume
94
Issue
6
Year of publication
1994
Pages
2183 - 2192
Database
ISI
SICI code
0021-9738(1994)94:6<2183:IOIMPG>2.0.ZU;2-6
Abstract
Retention of bile salts by the hepatocyte contributes to liver injury during cholestasis. Although cell injury can occur by one of two mecha nisms, necrosis versus apoptosis, information is lacking regarding apo ptosis as a mechanism of cell death by bile salts. Our aim was to dete rmine if the bile salt glycodeoxycholate (GDC) induces apoptosis in ra t hepatocytes. Morphologic assessment included electron microscopy and quantitation of nuclear fragmentation by fluorescent microscopy. Bioc hemical studies included measurements of DNA fragmentation, in vitro e ndonuclease activity, cytosolic free Ca2+ (Ca-i(2+)), and cytosolic fr ee Mg2+ (Mg-i(2+)). Morphologic studies demonstrated typical features of apoptosis in GDC (50 mu M) treated cells. The ''ladder pattern'' of DNA fragmentation was also present in DNA obtained from GDC-treated c ells. In vitro endonuclease activity was 2.5-fold greater with Mg2+ th an Ca2+. Although basal Ca-i(2+) values did not change after addition of GDC, Mg-i(2+) increased twofold. Incubation of cells in an Mg2+-fre e medium prevented the rise in Mg-i(2+) and reduced nuclear and DNA fr agmentation. In conclusion, GDC induces apoptosis in hepatocytes by a mechanism promoted by increases of Mg-i(2+) with stimulation of Mg2+-d ependent endonucleases. These data suggest for the first time that cha nges of Mg-i(2+) may participate in the program of cellular events cul minating in apoptosis.