Background: In photoaging, the accumulation of ultraviolet (UV)-induced oxidative damage
leads to the characteristic hallmarks of aging. Here arises the importance of autophagy as a
cellular degradation process that cleans the cells of defective or aged organelles and macromolecules,
thus maintaining cellular homeostasis. In spite of this, the exact impact of autophagy in
photoaging is still elusive.
Objective: To evaluate the protective effects of resveratrol and/or co-enzyme-Q10 against the
UVA-induced alterations and to explore the role of autophagy in their proposed benefits.
Methods: Sixty female mice were randomly divided into normal control, untreated UVA-exposed,
resveratrol (50mg/kg), co-enzyme-Q10 (100mg/kg), and resveratrol/co-enzyme-Q10-treated UVA--
exposed groups. Clinical signs of photoaging were evaluated using a modified grading score and
the pinch test. Skin malondialdehyde and reduced glutathione were assessed as markers of oxidative
stress. Tissues were examined for histopathological signs of photodamage, and autophagic
changes were determined by immunohistochemical detection of LC3 and P62 in the different cells
of the skin.
Results: UVA-exposure increased the oxidative stress with subsequent epidermal and dermal injury.
This was associated with the stimulation of autophagy in the keratinocytes and inhibition of
autophagic flux in the fibroblasts and infiltrating macrophages. Both drugs corrected the impaired
pinch test, macro–and microscopic changes, and exhibited distinct staining patterns with anti-LC3
and P62 in the different cell types denoting autophagic modulation.
Conclusion: Changes in autophagic flux are strongly implicated in photoaging associated skin damage
and the differential modulation of autophagy by resveratrol and, to a lesser extent by Co-enzyme-
Q10, is partially involved in their therapeutic benefits.