Quantitative gene expression analysis by cDNA microarray during liver regeneration after partial hepatectomy in rats.

Abstract

PURPOSE: It is speculated that genetic regulation plays an important role during liver regeneration. We conducted this study to analyze quantitative gene expression during liver regeneration after partial hepatectomy. METHODS: Sixty male Wistar rats were randomly assigned into ten groups of six. One group of rats was killed preoperatively and the other nine groups were killed 2, 4, 6, 12, 24, 48, and 72 h, and 5 and 7 days after 70% partial hepatectomy, respectively. The remnant livers were isolated for mRNA extraction. A mass survey of gene expression by cDNA microarray carrying 6144 polymerase chain reaction-amplified cDNA fragments was prepared by an arraying machine. The microarray images were scanned, digitized, and analyzed using a flatbed scanner. RESULTS: The variations in gene expression were classified into 72 different patterns including a pattern with a single peak, 2, 4, 6, 12, and 72 h, and 5 and 7 days after partial hepatectomy. The other patterns included double peaks, enhancing trend, diminished trend, protruding curve, excavated curve, and various mixed types. Each category of gene expression pattern contained 40-218 different proto-oncogenes. CONCLUSION: The quantitative gene expression profiles have important implications, warranting further investigation of the genetic mechanisms involved in the process of liver regeneration.