Biology Reference
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We also investigated the cytotoxic activity of RV on the tumor cells HL60: a hu-
man promyelocytic leukemia cell line. The results clarly show that RV can signifi -
cantly inhibit the cell growth already at a concentration of 25 μM.
Subsequently we assessed the level of cell mortality induced by Py infection: in
this case we used the method of vital cell staining only with trypan blue. As a matter of
fact, the MTT assay is informative of cell death deriving from membrane damage and
former data from our laboratory indicated that the plasma membrane is actually one of
the targets of RV. On the contrary, trypan blue staining has a more general action rang-
ing from a generic damage of cell membrane to severe problems in cell homeostasis.
Table 2 reports the vital cell counts in control and Py infected cells.
Table 2.
Assessment of the cell mortality rate due to Py proliferation.
Virus Py 24 h
Sample
Vital
Non-Vital
1
44
1
2
45
2
3
41
2
4
52
1
Average cell mortality 3,4% ± 1,5%
Virus Py 48 h
Sample
Vital
Non-Vital
1
40
2
2
46
4
3
44
4
4
49
2
Average cell mortality 6,7% ± 2,5%
The vital cell count was evalutated by trypan blue staining.
The reported data show that after 48 hr of infection the cell death rate is about as
double as in controls: however the viral infection does not seem to cause extensive
loss cell vitality.
In the light of these results the effect of RV on Py proliferation was evaluated at 24
hr post-infection in cells were treated with 20 μM RV or at the concentrations of drug
reported in the legends to the fi gures.
Effect of Resveratrol on the Viral Proliferation
Semi-confluent cells were infected with Py and RV was added after the absorption
phase at the indicated final concentrations. Infection was continued for 24 hr and prog-
eny viral DNA was extracted according to the Hirt-procedure [26] (Figure 2A). The
data clearly show that the viral replication is virtually abrogated at 20 μM RV. Infec-
tions performed in the presence of RV during the absorption phase gave essentially the
same results (not shown).
