PER2 Regulates Reactive Oxygen Species Production in the Circadian Susceptibility to Ischemia/Reperfusion Injury in the Heart

Figure 1

Circadian differences in susceptibility of the heart to I/R injury. (a) Experimental design. Mice were subjected to a protocol of 30 min of ischemia followed by 24 h of reperfusion starting at two time points, ZT2 or ZT14. ZT: zeitgeber time; ZT0: lights on. (b) Percent of area at risk over area of the left ventricle (middle). Percent of infarct over area at risk (right). AAR: area at risk; LV: left ventricle; MI: myocardial infarction (, ^& vs. ZT2). (c) Infarct size. Representative Evans blue and TTC staining (left). Percent of infarct over area at risk (right). White: infarct; red: viable; white+red: area at risk; blue: retrograde Evans blue staining, area not at risk (, ^& vs. IR-ZT2, two-tailed Student’s -test). (d) Cardiac systolic function of mice with I/R at ZT2 and ZT14. EF of the left ventricle (left), FS of the left ventricle (right). EF: ejection fraction; FS: fraction shortening; sham: sham surgery; I/R: ischemia-reperfusion. (–7, and vs. sham-ZT2; ^#### vs. sham-ZT14; ^& and ^&&& vs. IR-ZT2, two-tailed Student’s -tests). Alpha was set as 0.05. Data are presented as the . The Holm-Sidak method was used to correct for multiple -tests.

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