THE ROLE OF MRNA LEVEL OF THE NOTCH SIGNALING PATHWAY GENES IN INDUCED RAT LIVER FIBROGENESIS

Objectives. To study the role of mRNA level of the Notch signaling pathway genes in induced rat liver fibrogenesis. Material and methods. Fibrosis followed by the transition to liver cirrhosis in rats of Wistar line was induced with thioacetamide at a dose of 200 mg/kg of animal body weight twice a week for 17 weeks. The rats were randomized into 9 groups of 12 animals each. The mRNA level of the Notch signaling pathway genes was assessed by real-time PCR. The notch1, notch2, yap1 and hes1 genes were used as molecular targets. Microscopic analysis of histological preparations was performed using the OLYMPUS BX51 microscope. The degree of fibrosis was assessed according to the scale of Ishak K.G. Results. The study of the classical transcription factor of the Notch signaling pathway, hes1, revealed its very low and stable activity in all studied samples. The analysis of relative dynamics of the mRNA level of the notch1, notch2, and yap1 genes made it possible to determine marked changes in their levels at the point of transition from the normal state of liver tissues to the development of fibrosis. Conclusions. Within the framework of this study, the hes1 gene is not a target of the Notch pathway and can be used as a reference gene. The noted decrease in the mRNA level of the yap1 gene, probably, inhibits the compensatory-restorative processes in the liver, activates the stellate cells, and promotes the transformation of fibrosis into cirrhosis. In addition, it has been found that the revealed fluctuations in the mRNA levels of the notch1 and yap1 genes in relation to the starting point (there are no changes in the liver tissue) quite accurately describe the period of the onset of the transition of advanced fibrosis to cirrhosis. In this regard, they can be considered as potential markers of the transition of fibrosis to cirrhosis.