Experimental Study Of Associating Liver Partition With Portal Vein Ligation On Liver Regeneration In Rats

Objective: To establish a rat model of associating liver partition with portal vein ligation for staged hepatectomy(ALPPS) and investigate the effect of associating liver partition with portal vein ligation on liver regeneration in rats.Methods: Seventy-five healthy clean grade male Sprague-Dawley rats weighting 230 to 280 g were selected and assigned into three groups randomly: sham operation group(S), portal vein ligation group(PVL), associating liver partition with portal vein ligation group(ALPPS). Group PVL: The rats fasted 8h before the operation and were anesthetized with chloral hydrate injections(0.6ml/100g). Selective PVL was performed on the caudal lobe, left lateral and left median lobes, and the right lobe. The right median lobe was preserved to regenerate. After careful dissection of the hepatic artery and bile duct, the corresponding portal veins of the lobes were suture ligated with 5-0 silk; Group ALPPS: Besides the above steps, when the common trunk of the portal vein of the left lateral and left median lobe was ligated, the ischemic line emerged immediately at the right side of the falciform ligament. Then total liver parenchymal transection was performed along the ischemic line using the microscopic tweezers cutting the small parts of the liver parenchyma after ligating the left and right sections with an 8-0 silk suture until the entire liver parenchyma was completely transected. Some small vascular traffic branches were often encountered during splitting liver parenchyma. Electrocoagulation or suture ligature of 8-0 silk was used for hematischesis to hemorrhage of these communicating branches of small vessels in the transection surface. Next, the transection surface of the left median lobe was wrapped with a small piece of sterile plastic film to prevent adhesion to the two transection surfaces; Group S: the hepatic artery, portal vein and bile duct were dissected without ligation, and then the abdomen was closed. Each group was sacrificed on day 1, 3, 7, 10 and 14 after the operation(n = 5 for each time point). The blood samples collected at different time points were centrifuged at 3000 g for 10 min, and the serum was stored at-80℃ for detection. The right median lobe was taken for weighting, then the remnant liver lobes were fixed for paraffin embedding and frozen in liquid nitrogen and then stored at-80℃. the hepatic regeneration rate(HRR) of the right median lobe was calculated, the serum alanine aminotransferase(ALT), aspartate aminotransferase(AST) serum albumin(Alb), total bilirubin(TBil) and the serum IL-6, HGF, VEGF was detected and the m RNA of IL-6, HGF, TNF-α, TGF-β was assayed by real-time PCR as well as the histological changes was evaluated by stained with hematoxylin-eosin(H–E), the hepatic proliferating cell nuclear antigen(PCNA) labeling index was evaluated by immunohistochemistry.RESULTS:1. All animals in each experimental group were alive with good spirit and appetite, incision healed well with no infection occuring.2. The HRR of the right median lobe was obviously increased at each set time point in PVL group and ALPPS group more than S group. Compared with PVL group, the HRR of the right median lobe in ALPPS group obviously increased on day 3, 7, 10 and 14(P<0.05).3. Compared with S group, the concentration of ALT, AST was significantly higher on day 1 and 3(P<0.05). The concentration of ALT, AST in ALPPS group was higher than that in PVL group on day 1, then gradually decreased and returned to normal on day 7. The concentration of Alb in PVL group and ALPPS group was significantly lower than S group on day 1 and 3, and the concentration of Alb in ALPPS group was significantly lower than that in PVL group(P<0.05). There were no significant differences in the concentration of TBil at other time points(P>0.05).4. Compared with S group, the expression of IL-6, HGF, VEGF was significantly higher in PVL group and ALPPS group on day 1 and 3(P<0.05), and the expression in ALPPS group was higher than those in PVL group(P<0.05), then gradually decreased and returned to normal on day 7.5. Compared with S group, the expression of IL-6, HGF, TNF-α, TGF-βm RNA was obviously up-regulated on day 1 and 3(P<0.05), and peaked on day 1, then gradually decreased, the expression of IL-6, HGF, TNF-α, TGF-βm RNA in ALPPS group was higher than those in PVL group on day 1 and 3(P<0.05).6. On day 1,the PCNA labeling index in ALPPS group and PVL group was low(P>0.05), then gradually increased and peaked on day 3,and the positive expression of ALPPS group was higher than that of PVL group(P<0.05).7. On day 1,liver tissue H-E staining of ALPPS group showed disorder of liver cable structure, apparent cellular edema, fatty change, narrow Disse’s space, congestion, several focal necrosis. The PVL group showed no disorder of liver cable structure, and the necrosis area was small than that in ALPPS group. On day 3, the pathology of both groups was alleviated. Conclusion:1. The experiment successfully established a ALPPS rat model, and proved more severe early liver injury, and the accelerated hepatic regeneration compared with PVL group.2. The possible mechanisms of associating liver partition with portal vein ligation were related to the inflammation reaction and stress response caused by liver partition, with up-regulation of cytokines in the regenerating lobe, especially IL-6, HGF, TNF-α, VEGF and so on.