Autophagy Contributes to Liver Regeneration After Portal Vein Ligation in Rats

BACKGROUND This study investigated the effect of 70% portal vein ligation (PVL), a widely used procedure for inducing rapid liver regeneration, on the expression of autophagy-related proteins in non-ligated liver lobes in rats. MATERIAL AND METHODS Rats were subjected to either sham (n=30, major portal vein branches were exposed but kept intact) or PVL (n=30, major portal vein branches were double-ligated) operations. Liver samples were collected 12, 24, 48, 72, and 168 h after the operation. Liver volume, liver color, non-ligated liver percentage, and the expressions of light chain (LC) 3, beclin 1, and cyclin D1 in the non-ligated liver lobes were determined. RESULTS When compared to sham rats, increased (P<0.001) growth of the non-ligated liver lobes was observed in PVL rats as early as 12 h after surgery; an increased (P≤0.001) LC3 II/I ratio was observed in the non-ligated lobes of PVL rats as early as 24 h after surgery. Increased expressions of beclin 1 (P≤0.001) and cyclin D1 (P<0.001) were observed in the non-ligated lobes of PVL rats from 12 to 72 h after surgery and from 12 to 168 h after surgery, respectively, when compared to sham rats. In the non-ligated lobes, the expressions of beclin 1 and cyclin D1 were linearly and positively correlated with the LC3 II/I ratio. CONCLUSIONS Autophagy is activated in the non-ligated liver after PVL. Both beclin 1 and cyclin D1 are linearly and positively correlated with autophagy activity in the PVL-induced rapid liver regeneration model.