HIGH ALTITUDE INDUCED ALTERATION OF LIVER TRANSCRIPTOME IN RAT (Rattus Norvigicus)

Living at high altitude (HA) represent several risks to living organism mainly including oxidative stress and its associated metabolic disorders and hypoxia with its associated metabolic alterations. The focus of this study was to investigate the alteration of transcriptome in response to HA in Taif region. Two groups of rats were used in this study; sea level (SL) and high altitude (HL). RNA was isolated from rat liver and used in cDNA library construction, sequencing, and transcriptome analysis. Mapping of clean reads to the reference genome differed between SL and HL especially mapping to introns, where SL had more reads mapped to introns than HL. Co-expression of genes revealed that 754 genes were uniquely expressed in SL, 680 genes were uniquely expressed genes in HL, and 10197 genes were co-expressed in both groups. A total of 483 deferentially expressed genes (DEGs) were detected in HL compared to SL of which 250 were downregulated and 233 were upregulated. DEGs were used in the gene ontology (GO) and the KEGG pathway enrichment analysis. Forty-two GO terms were enriched including 15 biological process (BP) and 27 molecular functions (MFs), whereas no cellular components were enriched. The enriched terms included iron transport, transmembrane transport, oxidation-reduction process, ATP synthesis coupled proton transport, passive transmembrane transporter activity, and heme binding. Twenty-seven KEGG pathways were enriched including linoleic acid metabolism, nitrogen metabolism, drug metabolism-cytochrome P450, chemical carcinogenesis, necroptosis, and steroid hormone biosynthesis. Results of this study will contribute to us in depth understanding of HA impact on biological systems and how to enhance life at HA.