Abstract: Objective To investigate the effect of nicotine on the gene expression profile in prefrontal cortex (PFC) region of rat. Methods Twenty-four adult (8-weeks old) male F344 rats were randomly divided into treatment group and control group, with 12 animals in each group. Animals in treatment group were injected with nicotine solution while those in control group were given physiological saline for 17 days. At the end of drug administration, the tissue of PFC region was sliced from the brain of each animal. RNA sequencing was utilized to analyze the gene expression profile in PFC of each animal. Bioinformatics tools including Bowtie, Tophat and Cufflinks were used to map the sequencing reads to the reference genome of rat and to measure the relative expression level of each transcript. Genes whose expression levels were significantly different between the two groups were identified; the functional categories, as well as the biochemical pathways, associated with these genes were further analyzed. Results By comparing the expression level of each transcript between the nicotine treatment group and the control group, 885 significantly differentially expressed genes were identified. These genes were enriched in multiple Gene Ontology Biological Process categories (e.g., G protein coupled receptor protein signaling pathway, protein ubiquitination, and neurotransmitter uptake) and biological pathways (e.g., insulin signaling pathway, Alzheimer's disease, and long term potentiation). Conclusion Nicotine treatment may regulate biological processes like signaling transduction and energy metabolism in PFC of rat brain.

Key words: RNA sequencing, Nicotine addiction, Prefrontal cortex, Gene expression