Figure 3. TUNEL staining was used to quantify the degree of apoptosis in liver tissue after either 75 or 120 minutes of ischemia and 3 hours of reperfusion. Intermittent clamping (Interm.) and ischemic preconditioning (I/Pr) were both associated with a minimal number of apoptotic hepatocytes after 75 minutes of ischemia. Ischemic preconditioning did not completely prevent apoptosis after 120 minutes of ischemia but was still significantly lower than the controls (continuous ischemia only) (P = .001, analysis of variance; n = 5 per group; mean ± standard error).