TNF and ischemia: TNF-α concentration in the reperfusion group was much higher than that of the ischemia and sham groups (8.90 ± 1.43 vs. 6.28 ± 0.94 pg/mL, P < 0.05 and 8.90 ± 1.43 vs. 5.44 ± 1.58 pg/mL, P < 0.05, respectively) (Fig. 2).