Proteomics Analysis of Testis of Rats Fed a High-Fat Diet

The adverse effects of obesity on male fertility have been widely reported. In recent years, the relationship between the differential expression of proteins and long non-coding RNAs with male reproductive disease has been reported. However, the exact mechanism in underlying obesity-induced decreased male fertility remains unclear.

We used isobaric tags for relative and absolute quantification to identify differential protein expression patterns in the testis of rats fed a high-fat diet and normal diet. A microarray-based gene expression analysis protocol was used to compare the differences in long non-coding RNAs in high-fat diet-fed and normal diet-fed rats. Five obviously upregulated or downregulated proteins were examined using western blot to verify the accuracy of their expression. Then, we carried out functional enrichment analysis of the differentially expressed proteins using gene ontology and pathway analysis. Finally, the metabolic Gene Ontology terms and pathways involved in the differential metabolites were analyzed using the MetaboAnalyst 2.0 software to explore the co-expression relationship between long non-coding RNAs and proteins.

We found 107 proteins and 263 long non-coding RNAs differentially expressed between rats fed a high-fat diet and normal diet. The Gene Ontology term enrichment analysis showed that the protein function most highly enriched was related to negative regulation of reproductive processes. We also found five Gene Ontology terms and two metabolic pathways upregulated or downregulated for both proteins and long non-coding RNAs.

The study revealed different expression levels for both proteins and long non-coding RNAs and showed that the function and metabolic pathways of differently expressed proteins were related to reproductive processes. The Gene Ontology terms and metabolic pathways upregulated or downregulated in both proteins and long non-coding RNAs may provide new candidates to explore the mechanisms of obesity-induced male infertility for both protein and epigenetic pathways.