Transcriptome analysis of rat liver regeneration in a model of oval hepatic stem cells.

We have performed serial analysis of gene expression of the regenerating liver. In the rat model of partial hepatectomy and 2-acetamidofluorene treatment liver regeneration recruits hepatic stem cells referred to as oval cells. We analyzed a total of 153,057 tags in livers from normal control (52,343 tags), from sham 2-acetamidofluorene-treated control (50,502 tags), and from the early stage of oval cell proliferation (50,212 tags). Comparative analysis of the three transcriptomes identified 27 up-regulated and 18 down-regulated genes. Real-time PCR analysis confirmed 11 temporally regulated genes that correlate with oval cell development. Interestingly, we found by Western blot protein analysis of regenerating livers that the cell cycle gene Cdc42 was induced concomitant with the proliferation marker cyclin D1 and the oval cell marker alpha-fetoprotein. Our studies provide new insights into the molecular mechanism of liver regeneration through oval cells.