Zeni Eliane Cristina, Ammar Dib, Leal Mayana Lacerda, da Silva Heloisa Schramm, Allodi Silvana, Müller Yara Maria Rauh, Nazari Evelise Maria
Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil.
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Photochem Photobiol. 2015 Jul-Aug;91(4):869-78. doi: 10.1111/php.12457. Epub 2015 May 4.
High levels of ultraviolet-B (UVB) radiation can negatively affect aquatic animals. Macrobrachium olfersi is a prawn that lives in clear freshwaters and during the breeding season, females carry eggs in an external brood pouch. Therefore, we hypothesize that eggs are also exposed to environmental UVB radiation. The aim of this study was to investigate whether UVB radiation induces DNA damage and compromises cell cycle in embryos of M. olfersi. In laboratory, UVB irradiance (310 mW. cm(-2) ) that embryos receive in the natural environment was simulated. After irradiation, embryos were kept under different light conditions in order to recognize the presence of cell repair. UVB radiation induces DNA damage, specifically thymine dimers. After 48 h of UVB exposure, a significant decrease in the level of these dimers was observed in embryos kept under visible light while it remained constant in the dark. Moreover, under visible light and darkness, a decrease in proliferation was observed after 48 h of irradiation. An increase in PCNA expression and decrease in p53 expression were observed after, respectively, 1 and 48 h of exposure. Our results showed that UVB radiation disturbs the cell cycle and induces DNA damage in M. olfersi embryos. However, under visible light these embryos showed successful DNA repair.
高水平的紫外线B（UVB）辐射会对水生动物产生负面影响。奥氏沼虾是一种生活在清澈淡水中的虾类，在繁殖季节，雌性虾会将卵携带在体外的育卵囊中。因此，我们推测卵也会受到环境中UVB辐射的影响。本研究的目的是调查UVB辐射是否会诱导奥氏沼虾胚胎的DNA损伤并影响其细胞周期。在实验室中，模拟了胚胎在自然环境中所接受的UVB辐照度（310 mW·cm⁻²）。辐照后，将胚胎置于不同光照条件下，以识别细胞修复的存在情况。UVB辐射会诱导DNA损伤，特别是胸腺嘧啶二聚体。在UVB照射48小时后，在可见光下培养的胚胎中，这些二聚体的水平显著下降，而在黑暗中则保持不变。此外，在可见光和黑暗条件下，照射48小时后均观察到增殖减少。分别在照射1小时和48小时后，观察到增殖细胞核抗原（PCNA）表达增加和p53表达减少。我们的结果表明，UVB辐射会干扰奥氏沼虾胚胎的细胞周期并诱导DNA损伤。然而，在可见光下，这些胚胎显示出成功的DNA修复。
