[Differential expression of MAPK-pathway genes during liver regeneration of mouse.]

To investigate the different expression profiles of MAPK pathway genes and their corresponding functions during liver regeneration, we used a CCl4 induced mouse liver regeneration model in this study. Mouse was injected with CCl4 in the abdominal cavity to cause damage in the liver and followed by liver histology examination and measurement of serum ALT levels in blood sample collected at 0, 0.5, 1.5, 4.5, and 7 d after CCl4 injection. Differentially expressed genes in the MAPK pathway during liver regeneration were analyzed using mouse cDNA microarray method (Affymetrix). The results obtained were further subjected to hierarchical clustering study and were validated with real-time PCR. Microarray hybridization identified 31 out of the 93 MAPK pathway component genes, which have significantly altered their expression levels during liver regeneration. Among them, both up- and down-regulated genes were classified into various groups according to clustering studies and functional analysis. At the initial stage of liver regeneration, the number of up-regulated genes was greater than the down-regulated genes, while at the late stage the situation was reversed. Our results suggest that MAPK pathway might play different regulatory roles in responding to different stages of liver regeneration.