| The liver has many physiological functions and a vigorous ability of regeneration. When injured by physical, chemical, biological or pathological factors, hepatocytes can rapidly enter the cell cycle from the Go phase, together with other liver cells to compensate for the injury and/or lost liver tissues, and recover the function of liver, which is named as liver regeneration (LR). Hepatocyte proliferation plays a fundamental role in rat liver regeneration, which was regulated by many factors including growth factors, chemokines and signaling pathways. Previous studies on liver regeneration mostly focus on one or several genes/proteins. In fact, liver regeneration involves lots of genes and proteins, and complex interactions between them, which synergistically promote the completion of rat liver regeneration. Therefore, to highlight the molecular mechanisms of liver regeneration, it is necessary to study the kinds and function of liver regeneration-related genes/proteins at transcriptomic and proteomic levels.In order to reveal the ways and manners of hepatocytes proliferation in rat liver regeneration at transcriptomic and proteomic levels, this study isolated the hepatocytes using two-step collagenase perfusion and Percoll density gradient centrifugation. The expression changes of genes at post-PH 0,2,6, 12,24,30,36,72,120 and 168 h were determined by the Rat Genome 230 2.0 Array, and the expression changes of proteins in these ten time points were detected by two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) combined with mass spectrometry (MS). The differentially changed genes/proteins and liver regeneration-related genes/proteins were analysed by statistic methods. The interactions among them were analyzed by the Ingenuity Pathway Analysis 9.0 (IPA) and KEGG databases. The activity of the signal pathways and cell proliferation were calculated by spectral function (Ep(t)). The results showed that 4,654 genes were three times higher or lower than the control, which were called as meaningful expression genes, of them,3,869 were up-regulated,703 down-regulated, and 82 up/down-regulated.4,602 genes were significantly differences between partial hepatectomy (PH) group and sham operation (SO) group by F-test, which were named as LR-related genes with 3840 up-regulated,680 down-regulated and 82 up/down-regulated. It was also found that 1,169 proteins were twice higher or lower than the control, which were called as meaningful expression proteins. Among them,793 proteins were up-regulated,242 down-regulated, and 134 up/down-regulated.557 proteins, found to be significantly differences between PH group and SO group by F-test, were named as LR-related proteins with 485 up-regulated,36 down-regulated, and 36 up/down-regulated. Gene Ontology (GO) analysis showed that these genes/proteins were involved in 33 kinds of physiological activities. Among them,635 genes and 110 proteins participated in cell proliferation signaling pathways, and 1220 genes and 142 proteins in cell proliferation. Finally, synergistic effect (Ep(t)) analysis showed that the activities of signaling pathways of growth factors, chemokines and JAK/STAT were significantly increased at 6-72 h after PH. The activity of cell proliferation was also increased at the corresponding time. The network analysis showed that protein kinase AKT1 was located in the central node of the three pathways and increased at transcription and translation levels. In summary, the growth factors, chemokines and JAK/STAT signaling pathways may promote hepatocyte proliferation in the progressing phase of rat liver regeneration (6-72h after PH) via AKT1. |
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