Comparison of protective effect of ascorbic acid on redox and endocannabinoid systems interactions in in vitro cultured human skin fibroblasts exposed to UV radiation and hydrogen peroxide

Abstract

The mechanisms of biological activity of commonly used natural compounds are constantly examined. Therefore, the aim of this study was to compare ascorbic acid efficacy in counteracting the consequences of UV and hydrogen peroxide treatment on lipid mediators and their regulative action on antioxidant abilities. Skin fibroblasts exposed to UVA and UVB irradiation, treated with hydrogen peroxide and ascorbic acid. The redox system was estimated through reactive oxygen species (ROS) generation (electron spin resonance spectrometer) and antioxidants level/activity (HPLC/spectrometry) which activity was evaluated by the level of phospholipid metabolites: 4-hydroxynonenal, malondialdehyde, 8-isoprostanes and endocannabinoids (GC/LC-MS) in the human skin fibroblasts. Protein and DNA oxidative modifications were also determined (LC). The expression of nuclear factor erythroid 2-related factor 2 (Nrf2), its activators and inhibitors as well as pro/anti-apoptotic proteins and endocannabinoid receptors was examined (Western blot) and collagen metabolism was evaluated by collagen biosynthesis and prolidase activity (spectrometry). UVA and UVB irradiation and hydrogen peroxide treatment enhanced activity of xanthine and NADPH oxidases resulting in ROS generation as well as diminution of antioxidant phospholipid protection (glutathione peroxidase-glutathione-vitamin E), what led to increased lipid peroxidation and decreased endocannabinoids level. Dysregulation of cannabinoid receptors expression and environment of transcription factor Nrf2 caused apoptosis induction. Ascorbic acid partially prevented ROS generation, antioxidant capacity diminution and endocannabinoid systems disturbances but only slightly protected macromolecules such as phospholipid, protein and DNA against oxidative modifications. However, ascorbic acid significantly prevented decrease in collagen type I biosynthesis. Ascorbic acid in similar degree prevents UV (UVA and UVB) and hydrogen peroxide-dependent redox imbalance. However, this antioxidant cannot efficiently protect cellular macromolecules and avert metabolic dysregulation leading to apoptosis.

Nrf2 in cancers: A double‐edged sword

“…A number of natural compounds and synthetics have been identified as Nrf2 inhibitors, but currently none has yielded strong and practicable results. Ascorbic acid (Vitamin C) prevents Nrf2‐mediated redox imbalance caused by hydrogen peroxide and UV irradiation, however, cannot efficiently protect cells from apoptosis by metabolic dysregulation . Retinoic acid is a metabolite of dietary vitamin A, which binds to RARα and inhibits Nrf2 binding to the ARE .…”

Rutin and ascorbic acid cooperation in antioxidant and antiapoptotic effect on human skin keratinocytes and fibroblasts exposed to UVA and UVB radiation

“…However, this study demonstrates that when used in combination, ascorbic acid supports the uptake of rutin, thereby increasing its action [29], what is also shown in this study. The cytoprotective effect of ascorbic acid is mainly related to its antioxidant action in fibroblasts, while in keratinocytes ascorbic acid is a stimulator of cell proliferation and differentiation [21,71]. On the other hand, the cytoprotective effect of rutin on UV-treated fibroblasts is based on the coordination of fibroblast proliferation, and depending on the location of the cells, rutin may stimulate or inhibit their proliferation [30,33,44].…”

“…Protein antioxidants act to protect skin cells by supporting Nrf2, a ROS-dependent transcription factor, which initiates the transcription of cytoprotective and antioxidant genes [25]. Despite the maintenance of redox balance, frequent exposure of skin cells to the UVA and UVB radiation in natural sunlight stimulates pro-oxidative enzyme activity and impairs the action of antioxidants, resulting in oxidative stress [7,21]. Previous studies have shown that exposure to UVA and UVB radiation leads to the activation of many factors involved in mitogen-activated protein (MAP)-dependent signaling kinases, including ERK1/2 and transcription factors dependent on redox potential, e.g., Nrf2 [24,68].…”

“…Despite the differences in their chemical structure ( Fig. 1), rutin and ascorbic acid both show antioxidant and antiinflammatory effects and can be easily absorbed and transported from both skin surface and blood system [21,24,28]. When applied to the skin, ascorbic acid provides significant protection against inflammation and sunburn [3].…”

An evaluation of the antiaging properties of strawberry hydrolysate treatment enriched with L‐ascorbic acid applied with microneedle mesotherapy

“…Decreased fibroblast activity, reduced synthesis of collagen and elastin, increased transepidermal water loss (TEWL), and decreased melanocyte activity are observed in the course of aging. In addition, the immune system becomes weakened and oxidative stress response is impaired …”