Aging is accompanied by complex structural changes in the heart. To explore this remodeling, we used a serial optical coherence tomography scanner to image the entire heart at a microscopic resolution. The imaging platform combines optical coherence microscopy to vibratome sectioning to automatically image every subsection of the sample. Post-processing algorithms were then used to stitch back together the sample in a large 3D dataset. We imaged the heart of 7 young (4 months) and 5 old (24 months) wildtype mice (C57B16) with the imaging platform. Optical coherence tomography of the myocardium reveals myofiber orientation that changes linearly from the endocardium to the epicardium. This change in orientation also varies with the distance from the apex of the heart : close to the apex, the change in myofiber orientation with respect to wall depth is larger. In old mice, this change was lower when compared to young mice due to remodelling. As reported in other works, the average volume of old mice hearts (97 ± 3 mm3) was significantly larger (p<0.05) when compared to young hearts (87 ± 3 mm3). Myocardial wall thickening was accompanied by a reduction of light attenuation in the endocardium. Attenuation coefficient in old mice endocardium was measured at 15.4 ± 0.4 cm-1, compared to 18.6 ± 0.5 cm-1 in young mice, which was significantly lower (p<0.05). The use of a serial optical coherence tomography allows new insight into fine changes of the whole heart.
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