Fig. 4 a–e

Photomicrographs of the heart sections. a Normal heart histological architecture. b–d Sections from the positive control group, showing moderate congestion (red arrowhead), inflammatory neutrophilic infiltration (black arrowhead), hyaline degeneration (black arrow) (b), fatty infiltration of the cardiac muscles (red arrow) (b, c), and myxomatous degeneration of the cardiac muscles (d). e Cardiac sections from the IVM-treated group, showing occasional mild myxomatous degeneration. f Cardiac sections from the FLR-treated group, showing nearly normal cardiac histological architecture (H&E). For abbreviations, see Fig. 1