176 JOURNAL OF COSMETIC SCIENCE
Figure 1. PLE slows down growth and protects the amplifying capacity of human epidermal keratinocytes.
(A) Representative images of clonogenicity assays of keratinocytes cultured at low density for 10 days in the
presence or absence of PLE as indicated. Histogram: quantification of the number of colonies in A, grouped
by size (B) phase contrast images showing the representative morphology of keratinocytes cultured in the
presence of PLE (0.8mg/ml). Scale bar: 100 µm and (C) representative clonogenicity assays of keratinocytes
cultured or not in the presence or absence of PLE (0.8 mg/ml) for 8 days as indicated, then seeded for
clonogenicity assays as in A, in the absence of PLE. Data are mean ± SD of duplicate or triplicate samples,
representative of two to three independent experiments.

Figure
2.
PLE
delays
progression
of
epidermal
keratinocytes
through
the
G2-repair
phase
of
the
cell
cycle.
(A)
Representative
flow
cytometry
analyses
of
DNA
content
determined
by
propidium
iodide
(PI)
staining
of
cultured
primary
keratinocytes,
treated
or
not
with
PLE
for
8
days
as
indicated.
Quantitation
of
the
percent
of
cells
in
the
G1
or
the
G2/M
phase
of
the
cell
cycle
is
shown
on
the
right
histograms
(B)
representative
flow
cytometry
analyses
of
light
scatter
parameters
of
cultured
primary
keratinocytes,
treated
or
not
with
PLE
for
8
days,
as
indicated.
The
black
circle
corresponds
to
proliferative
cells
displaying
a
larger
size
typical
of
cells
in
the
DNA
repair
(R)
G2/M
phase
of
the
cell
cycle
(cells
are
twice
as
big).
Quantitation
of
cells
in
this
region
is
shown
on
the
right.
Data
represent
mean
±
SD
of
duplicate
samples,
representative
of
three
independent
experiments.
**p
0.01.
SSC:
Side
Scatter
FSC:
Forward
Scatter.
177 POLYPODIUM LEUCOTOMOS EXTRACT