Quantitative technique of protein mass spectrometry and KEGG pathway analysis
The protein sequencing and quantification were performed at Guangzhou Omicsmart Corp. Guangzhou, China. The L3-L5 segments of the spinal cord tissues were treated with lysis buffer (KeyGEN) for 30 min on ice, and then were homogenized using an ultrasonic homogenizer (Voshin, Wuxi, Jiangsu, China) for 2 min. The homogenate was centrifuged at 12000 rpm for 15 min at 4℃ and the supernatant was collected. The protein mass spectrometry was determined by direct data-independent acquisition (dDIA). To explore the biological functions of the different genes involved, gene ontology (GO) terms (http://www.geneontology.org/) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed using the cluster profiler method. The calculated p value was carried out through FDR correction, taking FDR ≤ 0.05 as a threshold. Protein-protein interaction (PPI) network was identified using string, which determined genes as nodes and interaction as lines in a network. The network file was visualized using cytoscape software (version 3.6.1) to present a core and hub gene biological interaction.