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Abstract
Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.
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Affiliation(s)
- Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Frank H Quina
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Maurício S Baptista
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
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Pipová Kokošová N, Kisková T, Vilhanová K, Štafuriková A, Jendželovský R, Račeková E, Šmajda B. Melatonin mitigates hippocampal and cognitive impairments caused by prenatal irradiation. Eur J Neurosci 2020; 52:3575-3594. [PMID: 31985866 DOI: 10.1111/ejn.14687] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 01/10/2020] [Accepted: 01/17/2020] [Indexed: 12/11/2022]
Abstract
Formation of new neurons and glial cells in the brain is taking place in mammals not only during prenatal embryogenesis but also during adult life. As an enhancer of oxidative stress, ionizing radiation represents a potent inhibitor of neurogenesis and gliogenesis in the brain. It is known that the pineal hormone melatonin is a potent free radical scavenger and counteracts inflammation and apoptosis in brain injuries. The aim of our study was to establish the effects of melatonin on cells in the hippocampus and selected forms of behaviour in prenatally irradiated rats. The male progeny of irradiated (1 Gy of gamma rays; n = 38) and sham-irradiated mothers (n = 19), aged 3 weeks or 2 months, were used in the experiment. Melatonin was administered daily in drinking water (4 mg/kg b. w.) to a subset of animals from each age group. Prenatal irradiation markedly suppressed proliferative activity in the dentate gyrus in both age groups. Melatonin significantly increased the number of proliferative BrdU-positive cells in hilus of young irradiated animals, and the number of mature NeuN-positive neurons in hilus and granular cell layer of the dentate gyrus in these rats and in CA1 region of adult irradiated rats. Moreover, melatonin significantly improved the spatial memory impaired by irradiation, assessed in Morris water maze. A significant correlation between the number of proliferative cells and cognitive performances was found, too. Our study indicates that melatonin may decrease the loss of hippocampal neurons in the CA1 region and improve cognitive abilities after irradiation.
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Affiliation(s)
- Natália Pipová Kokošová
- Department of Animal Physiology, Faculty of Science, Institute of Biology and Ecology, P. J. Šafárik University in Košice, Košice, Slovak Republic
| | - Terézia Kisková
- Department of Animal Physiology, Faculty of Science, Institute of Biology and Ecology, P. J. Šafárik University in Košice, Košice, Slovak Republic
| | - Katarína Vilhanová
- Department of Animal Physiology, Faculty of Science, Institute of Biology and Ecology, P. J. Šafárik University in Košice, Košice, Slovak Republic
| | - Andrea Štafuriková
- Department of Animal Physiology, Faculty of Science, Institute of Biology and Ecology, P. J. Šafárik University in Košice, Košice, Slovak Republic
| | - Rastislav Jendželovský
- Department of Cell Biology, Faculty of Science, Institute of Biology and Ecology, P. J. Šafárik University in Košice, Košice, Slovak Republic
| | - Enikő Račeková
- Institute of Neurobiology, Biomedical Research Center, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Beňadik Šmajda
- Department of Animal Physiology, Faculty of Science, Institute of Biology and Ecology, P. J. Šafárik University in Košice, Košice, Slovak Republic
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