Objective: To explore the effects of ischemic postconditioning on the remnant liver regeneration under ischemic reperfusion after subtotal hepatectomy.
Methods: A total of 90 male SD rats weighting 230-280 g were randomly divided into 3 groups of simple subtotal hepatectomy (SH), ischemia reperfusion (IR) and ischemic postconditioning (IPO). The left and middle liver lobes were resected. And the remnant liver was treated as follows: blood flow was non-blocked in SH group, but blocked for 30 min in IR group, then reperfused. The IPO group was established by 30-30 s intermittent interruptions of blood flow thrice during the early phase of reperfusion. At 1, 6, 12, 24, 48 h respectively, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatocyte growth factor (HGF) and the positive ratio of proliferating cell nuclear antigen (PCNA) were detected. Also the contents of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) were measured and the regenerated liver weight was calculated.
Results: The activities of ALT and AST in IPO group from 1 - 48 h were (138 ± 20), (340 ± 22), (770 ± 55), (389 ± 60), (113 ± 25) U/L and (247 ± 31), (509 ± 51), (972 ± 77), (955 ± 159), (222 ± 44) U/L respectively at each time point and they were significantly lower than those (294 ± 37), (560 ± 69), (1222 ± 162), (540 ± 40), (161 ± 15) U/L and (439 ± 34), (669 ± 94), (1347 ± 118), (1274 ± 223), (403 ± 68) U/L in IR group (P < 0.05); the regenerated liver weight (18.8 ± 3.2, 34.0 ± 3.5%) and positive cell ratio of PCNA (43.9 ± 2.7, 56.2 ± 4.0%) in IPO group at 24 and 48 h were respectively higher than those in IR group ((11.3 ± 2.9), (26.8 ± 2.5)% and (34.5 ± 2.8), (48.8 ± 1.8)%)(P < 0.05); The HGF levels ((261 ± 54) and (252 ± 103) pg/ml) at 24 and 48 h in IPO group were significantly higher than those ((99 ± 47) and (70 ± 19) pg/ml) in IR group (P < 0.05); the contents of ATP in hepatic tissue at 24 and 48 h in IPO group were (22.20 ± 3.6) and (12.87 ± 2.49) µg/g respectively. And they were significantly higher than those in IR group (P < 0.05), but lower than those in SH group (P < 0.05).
Conclusion: Ischemic postconditioning improves the remnant liver regeneration under ischemic reperfusion after subtotal hepatectomy through its actions of stimulating HGF production and maintaining hepatic energy metabolism.