Microfluidic high-throughput reverse-transcription quantitative PCR analysis of liver gene expression in lactating animals

We have evaluated a microfluidic lab-on-chip quantitative reverse transcription (RT) quantitative PCR (qPCR) method by measuring the expression of key actors of liver metabolism in lactating cattle. Animals in the early and in the late lactation phases were chosen because of the extreme adaptations in gene expression expected to occur. During the lactation cycle, 28 out of 48 genes were significantly regulated, notably in the same direction as previously shown by other techniques. This demonstrates that this high-throughput platform represents an attractive alternative to microarrays due to its ease of application, rapidity and lower costs. A set of 13 genes was identified—in combination with a dynamic PCA algorithm—that allowed the clearest separation between the two physiologically different groups. This paves the way for classification and diagnosis of animals in different metabolic situations by a reliable microfluidic RT-qPCR assay. Figure To determine the pattern of genes, which visualizes the separation of animals in the two lactation stages best, dynamic PCA was employed. A pattern of 13 genes was identified. Black dots represent the samples obtained from animals in early lactation and white dots represent samples from animals in late lactation.