Abstract: Objective To explore the role of the mammalian target of rapamycin(mTOR) signaling pathway in eight types of hepatic cells during rat liver regeneration (LR) at the gene transcription level. Methods Based on the establishment of the rat 2/3 hepatectomy model, isolation and identification of eight liver cell types from rat regenerating liver, detection of expression profiles of above eight liver cell types by Rat Genome 230 2.0 array, and application of quantitative real-time PCR, this study summarized and established the network of the mTOR signaling pathway, analyzed the expression profiles of mTOR signaling pathway-related genes in eight liver cell types during liver regeneration, and then applied systems biology method to analyze the physiological activities predicted by gene expression profiles. Results The mTOR signaling pathway was subdivided into 25 branches and contained a total of 110 genes. Among the 99 genes detected by arrays, 82 genes were identified as LR-related. At priming phase, mTOR signaling pathway was mainly involved in activating and promoting the growth of hepatocytes, pit cells, Kupffer cells, dendritic cells, hepatic stellate cells and sinusoidal endothelial cells. At the progressive phase, mTOR signaling pathway promoted the growth of hepatocytes, biliary epithelial cells, oval cells, hepatic stellate cells, Kupffer cells, pit cells and dendritic cells. At the terminal phase, the enhancement effect of mTOR pathway on the growth of hepatocytes, Kupffer cells and dendritic cells was remarkably reduced, but the inhibitory role of pathway 25 in the growth of hepatocytes, sinusoidal endothelial cells, hepatic stellate cells and pit cells was significantly increased.Conclusion The 25 branches and 82 genes involved in mTOR signaling pathway play a critical role in regulating the growth of eight cell types during rat liver regeneration.

Key words: Liver regeneration, mTOR signaling pathway, Eight liver cell types, Genome 230 2.0 array, Quantitative real-time PCR, Rat