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. 2021 May;20(5):653-661.
doi: 10.1007/s43630-021-00051-9. Epub 2021 May 19.

Low-power infrared laser modulates telomere length in heart tissue from an experimental model of acute lung injury

Larissa Alexsandra da Silva Neto Trajano  1   2   3 , Luiz Philippe da Silva Sergio  4 , Diego Sá Leal de Oliveira  4 , Eduardo Tavares Lima Trajano  5 , Marco Aurélio Dos Santos Silva  5 , Flavia de Paoli  6 , André Luiz Mencalha  4 , Adenilson de Souza da Fonseca  4   7
Affiliations

Low-power infrared laser modulates telomere length in heart tissue from an experimental model of acute lung injury

Larissa Alexsandra da Silva Neto Trajano et al. Photochem Photobiol Sci. 2021 May.

Abstract

Acute lung injury and acute respiratory distress syndrome can occur as a result of sepsis. Cardiac dysfunction is a serious component of multi-organ failure caused by severe sepsis. Telomere shortening is related to several heart diseases. Telomeres are associated with the shelterin protein complex, which contributes to the maintenance of telomere length. Low-power infrared lasers modulate mRNA levels of shelterin complex genes. This study aimed to evaluate effects of a low-power infrared laser on mRNA relative levels of genes involved in telomere stabilization and telomere length in heart tissue of an experimental model of acute lung injury caused by sepsis. Animals were divided into six groups, treated with intraperitoneal saline solution, saline solution and exposed to a low-power infrared laser at 10 J cm-2 and 20 J cm-2, lipopolysaccharide (LPS), and LPS and, after 4 h, exposed to a low-power infrared laser at 10 J cm-2 and 20 J cm-2. The laser exposure was performed only once. Analysis of mRNA relative levels and telomere length by RT-qPCR was performed. Telomere shortening and reduction in mRNA relative levels of TRF1 mRNA in heart tissues of LPS-induced ALI animals were observed. In addition, laser exposure increased the telomere length at 10 J cm-2 and modulated the TRF1 mRNA relative levels of at 20 J cm-2 in healthy animals. Although the telomeres were shortened and mRNA levels of TRF1 gene were increased in nontreated controls, the low-power infrared laser irradiation increased the telomere length at 10 J cm-2 in cardiac tissue of animals affected by LPS-induced acute lung injury, which suggests that telomere maintenance is a part of the photobiomodulation effect induced by infrared radiation.

Keywords: Low-power laser; Telomerase; Telomere length.

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Conflict of interest statement

The authors declare that they have no conflicts of interest.

Figures

Fig. 1
Fig. 1
Relative telomere length of normal and LPS-induced ALI animals. Wistar rats were inoculated with LPS, samples of heart tissue were collected, genomic DNA was extracted, and real time quantitative polymerase chain reactions were performed. (*) p < 0.05, compared to the control group. LPS: lipopolysaccharide. ALI: acute lung injury. n = 5: number of animals per group
Fig. 2
Fig. 2
Relative mRNA levels of TRF1 (a) and TRF2 (b) genes of normal and LPS-induced ALI animals. Wistar rats were inoculated with LPS and heart tissue samples were collected, total RNA extraction, complementary DNA synthesis and real time quantitative polymerase chain reactions were performed. (***) p < 0.001, compared to the control group. LPS: lipopolysaccharide. ALI: Acute Lung Injury. n = 5: number of animals per group
Fig. 3
Fig. 3
Relative telomere length of normal (a) and LPS-induced ALI (b) animals. Wistar rats were inoculated with LPS and, after 4 h, exposed to the low-power infrared laser at different fluences. Samples of heart tissue were collected, genomic DNA was extracted, and real time quantitative polymerase chain reactions were performed. (**) p < 0.05, compared to the control group, not irradiated; (##) p < 0.05, compared to the ALI group not irradiated. LPS: lipopolysaccharide. ALI: Acute Lung Injury. n = 5: number of animals per group
Fig. 4
Fig. 4
Relative mRNA levels of TRF1 (a) and TRF2 (b) genes of normal and LPS-induced ALI animals. Wistar rats were inoculated with LPS and, after 4 h, exposed to the low-power infrared laser at different fluences. Heart tissue samples were collected, total RNA extraction, complementary DNA synthesis, and real time quantitative polymerase chain reaction were performed. (*) p < 0.05, compared to the control group not irradiated. LPS: lipopolysaccharide. ALI: Acute Lung Injury. n = 5: number of animals per group
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