The effects of painful procedures during neonatal period on rats' hippocampal gene expression profiles in later life / 中国新生儿科杂志

ABSTRACT

Objective To study the effects of painful procedures during neonatal period on rats' hippocampal gene expression in later life.Method A total of 28 newborn male rats were randomly assigned into two equal groups.From day1 (P1) to day7(P7) after birth,rats in the pain group received four times of needle acupuncture at the foot everyday,simulating the infants' experience in the NICU.Rats in control group were touched at the same side of the foot with a cotton swab.Transcriptome sequencing of the hippocampus of the two groups were examined on day 8 (P8) and day 21 (P21).The gene expression profiles were established and the differentially expressed genes were screened for functional analysis.Quantitative Real-time polymerase chain reaction (qRT-PCR) was used to confirm these differentially expressed genes (GABRB1,GRIN2A,IL1 RAPL1) related to pain-stimulated response or brain cognition,and one of the key genes was further verified using Western blotting.Result The sequencing results showed that there were only 6 differentially expressed genes in hippocampal tissues of rats on P8 in the two groups.Howerer,the number increased to 53 on P21 and 85.0％ of these genes were down-regulated (45/53).Gene Ontology (GO) function enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the differentially expressed genes were mainly expressed on the cell membrane,voltage-gated ion channels,synapses,neurotransmitter receptors,immune responses,etc.The qRT-PCR and Western-blot results of key genes were consistent with the transcriptome sequencing.Conclusion Pain stimuli at an early stage after birth may trigger differentially expression of voltage-gated ion channel proteins,neurotransmitter receptors,and some key genes such as GABRB1 on hippocampal synaptic cell membranes in rats.These phenomenon may provide initial explanation for the molecular mechanism of early pain stimuli on neonatal brain development.