Fonseca A S, Campos V M A, Magalhães L A G, Paoli F
Laboratório de Ciências Radiológicas, Departamento de Biofísica e Biometria, Instituto de Biologia Roberto Alcântara Gomes, Rio de Janeiro, RJ, BR.
Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Juiz de Fora, MG, BR.
Braz J Med Biol Res. 2015 Oct;48(10):929-38. doi: 10.1590/1414-431X20154457. Epub 2015 Jul 10.
Low-intensity lasers are used for prevention and management of oral mucositis induced by anticancer therapy, but the effectiveness of treatment depends on the genetic characteristics of affected cells. This study evaluated the survival and induction of filamentation of Escherichia coli cells deficient in the nucleotide excision repair pathway, and the action of T4endonuclease V on plasmid DNA exposed to low-intensity red and near-infrared laser light. Cultures of wild-type (strain AB1157) E. coli and strain AB1886 (deficient in uvrA protein) were exposed to red (660 nm) and infrared (808 nm) lasers at various fluences, powers and emission modes to study bacterial survival and filamentation. Also, plasmid DNA was exposed to laser light to study DNA lesions produced in vitro by T4endonuclease V. Low-intensity lasers:i) had no effect on survival of wild-type E. coli but decreased the survival of uvrA protein-deficient cells,ii) induced bacterial filamentation, iii) did not alter the electrophoretic profile of plasmids in agarose gels, andiv) did not alter the electrophoretic profile of plasmids incubated with T4 endonuclease V. These results increase our understanding of the effects of laser light on cells with various genetic characteristics, such as xeroderma pigmentosum cells deficient in nucleotide excision pathway activity in patients with mucositis treated by low-intensity lasers.
低强度激光用于预防和治疗抗癌治疗引起的口腔黏膜炎，但治疗效果取决于受影响细胞的遗传特征。本研究评估了核苷酸切除修复途径缺陷的大肠杆菌细胞的存活和丝状化诱导情况，以及T4内切核酸酶V对暴露于低强度红光和近红外激光的质粒DNA的作用。将野生型（AB1157菌株）大肠杆菌和AB1886菌株（uvrA蛋白缺陷）的培养物暴露于不同能量密度、功率和发射模式的红色（660 nm）和红外（808 nm）激光下，以研究细菌的存活和丝状化。此外，将质粒DNA暴露于激光下，以研究T4内切核酸酶V在体外产生的DNA损伤。低强度激光：i）对野生型大肠杆菌的存活没有影响，但降低了uvrA蛋白缺陷细胞的存活，ii）诱导细菌丝状化，iii）不改变琼脂糖凝胶中质粒的电泳图谱，iv）不改变与T4内切核酸酶V孵育的质粒的电泳图谱。这些结果增进了我们对激光对具有各种遗传特征的细胞的影响的理解，例如在接受低强度激光治疗的黏膜炎患者中，核苷酸切除途径活性缺陷的着色性干皮病细胞。
