To investigate apoptotic and necrotic cell death, we have
used a phosphatidylserine-binding protein (Annexin-V-FITC)
to detect apoptosis-dependent redistribution of phospholipid.
Cells were also counter-stained with PI to distinguish apoptosis
from necrosis. We found few apoptotic and necrotic cells in
shcontrol BMSCs, an increase in response to oxidant, and a
substantial block of this effect by Vitamin C. However, with
decreased transporter levels, shSVCT2 BMSCs showed significantly
higher apoptotic and necrotic cells. Moreover, supplementation
with vitamin C to shSVCT2 BMSCs did not block
oxidative stress-induced apoptosis and necrosis. Recently,
Song et al (2014) reported that autophagy is critical for the
BMSCs' survival under oxidative conditions. Furthermore,
other investigators also reported that low level or acute
exposure induces autophagic flux, whereas chronic or high
dose oxidative treatment blocks autophagy and enhances
apoptosis in a number of cell types (Song et al, 2014; Boya et
al, 2005; Zhou et al, 2012). We speculate that knockdown or
down-regulation of SVCT2 transporter disturbs cell antioxidant
properties because of less availability of vitamin C
which leads to weaker cell survival mechanism. Vitamin C is
known for its antioxidant dependent autophagy and cell