31 Julio 2017
Administrator

Abstract

Skin is continuously exposed to a variety of environmental stresses, including ultraviolet (UV) radiation. UVB is an inherent component of sunlight that crosses the epidermis and reaches the upper dermis, leading to increased oxidative stress, activation of inflammatory response and accumulation of DNA damage among other effects. The increase in UVB radiation on earth due to the destruction of stratospheric ozone poses a major environmental threat to the skin, increasing the risk of damage with long-term consequences, such as photoaging and photocarcinogenesis. Extracts from plants and natural compounds have been historically used in traditional medicine in the form of teas and ointments but the effect of most of these compounds has yet to be verified. Regarding the increasing concern of the population with issues related to quality of life and appearance, the cosmetic market for anti-aging and photoprotective products based on natural compounds is continuously growing, and there is increasing requirement of expansion on research in this field. In this review we summarized the most current and relevant information concerning plant extracts and natural compounds that are able to protect or mitigate the deleterious effects caused by photoaging in different experimental models.

 

Introduction

Skin is the outermost organ of the body and is subjected to environmental damage such as sunlight and pollution among others. Skin aging is the result of two synergistic mechanisms: intrinsic or chronological aging, a process that occurs not just to the skin but to all tissues and is a result of passage of time; and extrinsic aging, or photoaging, which is caused by repetitive exposure of the skin to damaging agents, especially sunlight (Naylor et al. 2011). UVB is the most dangerous component of sunlight. Due to its high energy, UVB is able to cross the epidermis and reach the upper dermis where is interacts with cellular chromophores, leading to DNA damage and increased oxidative stress (Trautinger 2001; Cavinato and Jansen-Dürr 2017). These events activate innumerous signaling pathways that lead to decreased collagen production, increased synthesis and activity of matrix metalloproteases (MMPs) which are responsible for connective tissue degradation, accumulation of senescent cells, synthesis and accumulation of the senescence-associated secretory phenotype (SASP) components and defective degradation of elastic fibers (Cavinato et al. 2016; Cavinato and Jansen-Dürr 2017) (Fig. 1). Macroscopically, these events result in the appearance of wrinkles, increased epidermal thickness with consequent increased dehydration, hyperpigmentation, sallowness, and loss of skin tone, which are the main characteristics of photoaged skin (Quan et al. 2004). The increment in UVB radiation on earth due to the destruction of the ozone layer, is a major environmental threat to the skin, increasing the risk of damage with long-term consequences, such as photoaging, photoimmunosuppression and photocarcinogenesis (Decean et al. 2016).

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31 Julio 2017
Administrator

Abstract

The physiological and ultrastructural effects induced by acute exposure to ozone (O3) were investigated in the lichen Xanthoria parietina. Our working hypothesis was that parietin content and hydration of the thalli may play a role in the modulation of the effects of O3exposure. Four batches of X. parietina samples, dry and wet, with (P+) and without (P−) parietin, were fumigated for 1 h with 3 ppm O3. The effects of O3 were assessed immediately after the fumigation and after one week of recovery under controlled conditions. O3 fumigation caused physiological and ultrastructural impairment both to the photobiont and the mycobiont,irrespective if samples were fumigated wet or dry, and P+ or P−. However, one week after fumigation, a recovery was observed in P+ samples for the photobiont and in dry samples for the mycobiont. We suggest that the hydration state may play a major role in determining the severity of the damage, while the presence of parietin may promote the recovery. Our results provide physiological and ultrastructural basis to explain the ecological insensitivity of lichens to high environmental levels of ozone occurring during dry Mediterranean summers.

 

Keywords

Air pollution Biomonitoring Chlorophyll a fluorescence Ergosterol Parietin 

Responsible editor: Philippe Garrigues.

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31 Julio 2017
Administrator

OBJECTIVES: Medication-related osteonecrosis of the jaws (MRONJ) is an extremely therapy-resistant disease involving the jaws especially following bisphosphonate treatment. Bisphosphonates accumulate in bone in concentrations sufficient to be directly toxic to the oral epithelium. Current therapeutic options are inadequate for the prevention and treatment of MRONJ. The aim of this study was to investigate effects of ozone gas plasma therapy on wound healing in bisphosphonate-applied human fibroblasts.

MATERIAL AND METHODS: Human primary gingival fibroblasts were cultured. Cytotoxic concentrations (IC50) of bisphosphonates (pamidronate (PAM), alendronate (ALN), and zoledronate (ZOL)) were determined by MTT test. A 60 μg/μl for 30 s of ozone gas plasma application was performed to all experimental culture flasks after drug treatment at 24-h intervals as 3 s/cm(2). Genotoxic damages were evaluated by comet assay and wound healing was determined by in vitro scratch assay.

RESULTS: PAM, ALN, and ZOL applications caused genotoxic damage on primary human gingival fibroblast DNA. Ozone gas plasma therapy significantly decreased the genotoxic damage (p < 0.05), and this application provided 25, 29, and 27% less genotoxic damage in order of ALN, PAM, and ZOL groups. Ozone gas plasma therapy significantly increased wound healing rates both in postsurgical 24th and 48th hours for all doses of experimental drug groups (p < 0.05).

CONCLUSION: The ozone gas plasma application decreased genotoxic damage effect of bisphosphonate usage while improved the wound closure rate on human gingival fibroblasts.

CLINICAL RELEVANCE: Ozone gas plasma therapy may be helpful in prevention of gingival healing delay in MRONJ pathogenesis especially when applied simultaneously with surgical intervention.

 

 

 

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