Figure 2.

Second harmonic generation (SHG) imaging demonstrates disorganized sarcomere pattern in DCM hearts. (a) The sarcomere pattern in WT hearts closer to the inner chamber is discernible, is well-organized, and has low levels of collagen (green) (scale bar, 133 μm). (b) In contrast, DCM hearts lack an organized sarcomere pattern (scale bar, 50 μm). (c) High magnification (HM) image of an area in (b), showing clear loss of sarcomeric structure in these swollen areas. Green channel is backward SHG (BSHG) depicting predominantly collagen fibers, red channel is autofluorescence (AF), and blue channel is forward directed SHG (FSHG) showing sarcomere pattern and their merge. (d) Fast Fourier Transformation (FFT) analysis of the sarcomere pattern in WT and DCM hearts from the inner chamber area to distal parts of the hearts. (e) FFT of the whole frames in (d), note the fuzziness in the high frequency pattern. However, the localized changes in sarcomere pattern could not be discerned while doing whole frame FFT analysis. (f) FFTs of regions of interest (1, 2, and 3) from the inner chamber of heart to distal part as depicted in highlighted areas in (d) showing the region specific disorganization in sarcomeric pattern. Note there is no difference in FFT pattern in location 3 of both WT and DCM hearts, although, in regions closer to the inner chamber (2) and especially in swollen regions (1), there is a substantial difference in DCM hearts but there are no discernible differences in WT. Images ((a)–(d)) are representative of multiple locations of 2 hearts (n = 2).