Mechanism of benzo (k) fluoranthene induced reproductive damage in mice based on proteomics and metabolomics analysis

To explore the potential mechanism of Benzo (K) fluoranthene (BkF) on male reproductive injury in mice by proteomics and metabolomics.

Twenty healthy and clean male Kunming mice (6 weeks old, 18±2 g) were randomly divided into control group (corn oil group), low-, medium- and high-dose BkF groups (7.5, 15.0 and 30.0 mg/kg), with 5 mice in each group. The corresponding agents were gavaged at a dose of 10 mL/kg, 5 d per week, for 35 consecutive days. After modeling, the rats were fasted for 10 h, and then sperm samples and testicular tissues were harvested. Computer assisted sperm analysis (CASA) was used to detect and analyze semen parameters. HE staining was employed to observe the histopathological structure of the testicular tissue. Bioinformatics analysis was applied to analyze the differential protein pathways. Volcano plot were conducted to analyze the top 10 differentially expressed proteins (DEPs) in the control and high-dose BkF group. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) untargeted metabolomics techniques were utilized to screen out differential metabolites. KEGG signaling pathway and KEGG annotation analyses and GO enrichment analysis were used to analyze the differential metabolites.

Compared with the control group, the sperm number and motility of BkF-treated mice showed a decreased trend, with statistical differences (P<0.05). Pathological observation showed that BkF treatment resulted in dilated seminal tubules and badly-arranged spermatogenic cells when compared with the control group. Proteomics analysis found that the protein levels of Spata46 and Rab5b were decreased, while those of Zscan21 and Aifm2 were increased (P<0.01). Proteomic KEGG enrichment analysis showed that it was mainly involved in phagosome, protein export, ribosome and other pathways. GO enrichment analysis indicated that it was mainly involved in male meiosis I, histone acetylation, regulation of p53 signaling pathway, positive regulation of cell cycle, positive regulation of cell death and other signaling pathways. Metabonomics KEGG displayed that amino sugar and nucleotide sugar metabolism were most closely related to other metabolic pathways.

Proteomics and metabolomics analyses show that BkF exposure is associated with spermatogenesis, apoptosis and cell cycle, DNA damage, amino sugar and nucleotide sugar metabolism.