The variation of AkT/TSC1-TSC1/mTOR signal pathway in hepatocytes after partial hepatectomy in rats

Objective: The aim of this study was to investigate the role and regulatory mechanisms of Akt/TSC1-TSC2/mTOR signal pathway on the hepatocyte growth and proliferation after partial hepatectomy in rats. Methods: We used the animal model of 70% hepatectomy, separated and cultivated hepatocytes. According to the different time points after partial hepatectomy, it could be grouped into 0 h, 2 h, 6 h, 24 h and 72 h. According to the different kinds of specific inhibitor in the nutritive medium after the separation of hepatocytes, it could be grouped into Triciribine (TR), Rapamycin (RA) and Control (CO). We investigated (3)H-Leucine incorporation into protein, the cross section areas of hepatocytes, and detected cell cycle through FCM. The expressions of phosphorylated protein TSC2 and mTOR were observed. Results: (1) The content of phosphorylated protein TSC2 in group CO began to increase at 2 h and got to the peak at 6 h but declined at 24 h. The content of phosphorylated protein TSC2 in group RA had the same variation with that of phosphorylated protein TSC2 in group CO. (2) At the time point of 0 h, 2 h, 6 h and 24 h after operation, the incorporation efficiency of 3 H-Leucine in groups RA and TR was different from that in group CO in statistics (P<0.01). (3) It could be seen that the cross section areas of hepatocytes in groups RA and TR were different from that in group CO in statistics at 2 h and 6 h after operation (P<0.05). (4) Comparing with the other two inhibitor groups (TR and RA), the number of cells during the period of G(0)/G(1), in group CO became fewer, while the number of cells during the period of S and G(2)/M grew obviously (referring to Fig. 8). After operation, each time point was different from the inhibitor groups obviously (P<0.05 or P<0.01). The peak declined greatly at 24 h and 72 h after operation. Conclusions: These data strongly suggest the effects of Akt/TSC1-TSC2/mTOR signal pathway on hepatocyte growth, protein synthesis and cell cycle, and prove its contribution to liver regeneration. (C) 2009 Published by Elsevier Inc.