Oxidative stress causes relocation of the lysosomal enzyme cathepsin D with ensuing apoptosis in neonatal rat cardiomyocytes.

摘要: Abstract Exposing neonatal rat heart myocytes to the redox cycling quinone naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) for 15 45 minutes led a time-dependent release of cathepsin D from many secondary lysosomes cytosol, as analyzed by morphometry. Cathepsin was detected electron microscopically using pre-embedding immunostaining technique that utilizes antibodies conjugated ultra-small (0.8-nm) gold particles and subsequent silver enhancement. The exposure also caused decrease in both pH ATP level cells within same time frame. Lipid peroxidation was, however, not detected. Pretreatment cultures with alpha-tocopherol succinate prevented relocation, shown immunofluorescence. After naphthazarin, were washed, normal culture conditions re-established 18 hours. Many then showed apoptotic morphology (ie, cellular shrinkage chromatin condensation) Giemsa staining. Also, 41% stained positive TUNEL technique, DNA fragmentation separation intact fragmented DNA. Apoptosis significantly decreased pretreated succinate.