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Figure 1 Senescent Animals Exhibited Impaired Phagocytosis of Dead Cardiomyocytes and Decreased Peak Neutrophil Infiltration in the Infarcted Myocardium

(A) After 72 h of reperfusion, young mice showed almost complete replacement of dead cardiomyocytes with granulation tissue (arrows). (B) In contrast, at the same timepoint senescent mouse infarcts exhibited delayed granulation tissue formation and persistent presence of nonphagocytosed cardiomyocytes (arrows). (C to E). Neutrophils were identified in young mouse infarcts after 24 h (C), 72 h (D), and 7 days (E) of reperfusion. Young animals showed intense neutrophil infiltration of the infarcted myocardium, peaking after 24 h of reperfusion. (F to H) Neutrophil staining in senescent mouse infarcts after 24 h (F), 72 h (G), and 7 days (H) of reperfusion. (I) Senescent mouse infarcts had decreased peak neutrophil infiltration but exhibited timely resolution of the neutrophilic infiltrate (*p < 0.05 vs. young).