Oxidative stress causes relocation of the lysosomal enzyme cathepsin D with ensuing apoptosis in neonatal rat cardiomyocytes
1998 (English)In: American Journal of Pathology, ISSN 0002-9440, E-ISSN 1525-2191, Vol. 152, no 5, 1151-1156 p.Article in journal (Refereed) Published
Exposing neonatal rat heart myocytes to the redox cycling quinone naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) for 15 to 45 minutes led to a time-dependent release of cathepsin D from many secondary lysosomes to the cytosol, as analyzed by morphometry. Cathepsin D was detected electron microscopically using a pre-embedding immunostaining technique that utilizes antibodies conjugated to ultra-small (0.8-nm) gold particles and subsequent silver enhancement. The exposure to naphthazarin also caused a decrease in both the pH and the ATP level of the cells within the same time frame. Lipid peroxidation was, however, not detected. Pretreatment of the cultures with alpha-tocopherol succinate prevented cathepsin D relocation, as shown by immunofluorescence. After exposure to naphthazarin, cells were washed, and normal culture conditions were re-established for 18 hours. Many cells then showed apoptotic morphology (ie, cellular shrinkage and chromatin condensation) as analyzed by Giemsa staining. Also, 41% of the cells stained positive with the TUNEL technique, and DNA fragmentation was detected by separation of intact and fragmented DNA. Apoptosis was significantly decreased in cultures pretreated with alpha-tocopherol succinate.
Place, publisher, year, edition, pages
1998. Vol. 152, no 5, 1151-1156 p.
National CategoryMedical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-80994PubMedID: 9588882OAI: oai:DiVA.org:liu-80994DiVA: diva2:549675