Liver regeneration after portal vein plus hepatic artery ligation performed heterochronously in rats.

BACKGROUND/PURPOSE Portal vein ligation (PVL) has been used clinically to decrease the amount of liver before surgical resection, consequently, minimizing postoperative dysfunction in the remaining hypertrophied liver lobes. To date, few reports in the literature have demonstrated the regenerative capacity of unaffected lobes following PVL plus hepatic artery ligation (HAL). This study was conducted in rats to determine a safe and efficacious method of PVL plus HAL, focusing on liver function, the MIB-5 labeling index, and the ratio of the weight of the nonligated lobes to the body weight. METHODS Group I rats were subjected to PVL of the left lateral and median branches alone (corresponding to approximately 70% total liver volume). In group II, we performed PVL and HAL of the same branches simultaneously, while in group III, HAL was performed 48 h after PVL. A laparotomy without ligature was performed in the control group. Rats from each group were killed at 24, 48, 72, 96, and 168 h after surgery. Standard serum liver functions were tested. Proliferative activity in the nonligated liver was expressed using the Ki-67 antigen (MIB-5) labeling index. Body and nonligated lobe weights were measured. RESULTS At 96 h post-surgery, the ratio of the weight of the nonligated lobe to body weight was significantly higher in group III than in group I and group II, and induction of the MIB-5 labeling index showed maximum levels in group III. However, quantitative determination of serum glutamic-oxaloacetate transaminase (GOT) showed peak levels in group II at 24 h after surgery. CONCLUSIONS From these results, we conclude that the PVL plus HAL heterochronous procedure is safer and more efficacious than PVL only, or simultaneous PVL plus HAL. A better knowledge of the events following such heterochronous ligation should improve the clinical outcome of hepatic resection for liver diseases.