All of the three rats in the experimental group that received quercetin loaded exosomes showed increase in the size of cardiomyocyte nuclei with the appearance of multinucleated cardiomyocytes, two exhibited cardiomyocyte hypertrophy and focal hyper-eosinophilia, and one animal displayed perivascular lymphocytic infiltration (Table 1). Focal myocytolysis was also observed: some cardiomyocytes appeared ”empty,” i.e., without nuclei and cross striation, and their cytoplasm stained more intensely eosinophilic (Figure 7). Mild myocardial artery atherosclerosis and interstitial fibrosis were observed in all animals, and a minimal degrees of perivascular fibrosis was found in one and a mild form in another (Table 1). However, all of the animals in the quercetin only group exhibited cardiomyocyte hypertrophy; increased size of cardiomyocyte nuclei with the appearance of multinucleated cardiomyocytes, mild myocardial artery atherosclerosis, and mild interstitial fibrosis (Table 1). One of the animals in this group had focal hyper-eosinophilia, and using Masson’s trichrome staining, one animal showed minimal perivascular fibrosis, and the other two showed mild perivascular fibrosis (Table 1).