Impact of prolonged acoustic contamination on the structure and activity of the heart.

Acoustic contamination in urban areas (and elsewhere) can lead to stress conditions, particularly when prolonged. The mechanisms by which stress alters the heart's function are the subject of fast-growing scientific interest. The purpose of the present work is to establish a mouse model of persistent acoustic contamination to study the impact of this specific type of stress on the structure and function of the heart, particularly at the single-cell level. To this end, we are planning to realize a box made of aluminum to isolate sounds and light. Incorporating loudspeakers in it will permit to play sounds in a pressure range of 75-83 dB in which female and male mice will be exposed to acoustic pollution for 4 days. At the end of the protocol, the hearts of these mice will be isolated and perfused according to Langendorff to evaluate the function of the whole heart and to obtain isolated cardiomyocytes to study them from a molecular and functional point of view. In addition to functional studies like sarcomere shortening and Ca2+ transient, we will assess molecular signatures of stress-related signaling, such as oxygen free radicals and brain- derived neurotrophic factor (BDNF).The present work will elucidate – for the first time – whether a direct exposure to Acoustic contamination is penetrant enough to affect heart function at a single directly cell (myocyte) level.