Efeito da terapia de luz azul na resposta cognitiva, emocional e de atividade-repouso em roedores jovens e idosos

Abstract

Aging represents a natural, progressive, and heterogeneous event that all living beings undergo. However, physiological or behavioral changes may occur in different ways among individuals, raising questions regarding the relationship between the aging process and the alteration of these functions, such as cognitive decline. In this sense, various therapies, including non-invasive ones such as phototherapy, have been tested on cognitive aspects in aged human and non-human individuals. Few studies show the effects of blue light therapy on the behavior of aged animals when compared to young animals. In this study, the effect of blue light therapy on cognitive and emotional aspects and on the expression of activity-rest rhythms was evaluated in young and old rats. For this purpose, animals aged 3 and 20 months (young and old, respectively) were subjected to behavioral tests such as the open field (OF) and object recognition before and after treatment with blue light. This therapy was applied for a period of 14 days, under a L-L-D cycle of 6:6:12 hours, with blue light applied in the early hours of the light cycle. It was observed that blue light therapy improved the activity and resting rhythm of both animals about relative amplitude and acrophase, however in the OF test and object recognition the aged animals did not show significant changes. Young animals, on the other hand, showed significant results only in the OF test about the total distance covered and exploration of the device areas. We believe that more investigations are needed to better understand the effect of blue light on cognitive and emotional responses, so that memory, as well as the neural mechanisms related to it, are better understood.