Transcriptional alterations of genes related to fertility decline in male rats induced by chronic sleep restriction

The adverse effects of sleep disorders on male fertility are of increased concern. In this study, a rat model of chronic sleep restriction (CSR) was established using the modified multiplatform method. The effects of CSR on the fertility of male rats were evaluated first based on sexual behavior. Serum hormones, including testosterone (T), prolactin (PRL), luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and sperm parameters (concentration, viability, motility, deformation rate) were measured, and testicular histology was analysed by hematoxylin and eosin staining. The transcriptional differences between CSR rats and control rats were detected by RNA sequencing (RNA-Seq), and DNA methylation was then detected by bisulfite sequencing. After the differentialy expressed genes of CSR rats were sequenced and screened, representative up- and down-regulated genes were randomly sampled to verify the sequencing results by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Finally, functional annotations were completed, including gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomic (KEGG) pathway analyses. The results showed that the sexual behavior of CSR rats did not change when compared with control group rats. The sperm concentration, viability and motility of the CSR rats decreased significantly, while the sperm malformation rate increased significantly. In the KEGG pathway analysis database, some specific differentially expressed genes were screened, which are involved in metabolic pathways, inflammation-related pathways, the renin-angiotensin system, as well as others. However, the aforesaid differentially expressed genes in the testes were not related to their DNA methylation status. CSR could significantly reduce the fertility of male rats, and one of its mechanisms occurs by altering gene expression in the testes, which is not related to their state of DNA methylation. The results of this study suggest that CSR could cause male infertility by significantly altering the testicular transcriptome.Abbreviations: CSR: chronic sleep restriction; SD: sleep deprivation; RNA-Seq: RNA sequencing; NGS: next generation sequencing; qRT-PCR: real-time quantitative reverse transcription polymerase chain reaction; KEGG: Kyoto encyclopedia of genes and genomic; NO: nitric oxide; INOS: Inducible nitric oxide synthase; Il6: interleukin-6; Tnf: tumour necrosis factor alpha; Hsd11b1: hydroxysteroid 11-beta dehydrogenase 1; Dnmt3a: DNA methyltransferase 3Ax; PSD: paradoxic sleep deprivation; DNMTs: DNA methyltransferases family; REM: rapid eye movement sleep; PGD: preimplantation genetic diagnosis; PGS: preimplantation genetic screening; ECS: expanded carrier screening; T: testosterone; FSH: follicle stimulating hormone; LH: luteinizing hormone; PRL: prolactin; BC group: Blank Control group; MC group: Model Control group; Hist1h2ba: histone cluster 1 H2ba; Lgr4: leucine-rich repeat-containing G protein-coupled receptor 4; Atrn: attractin ; Ogg1: 8-oxoguanine DNA glycosylase; SNVs: single nucleotide variants ; HPG axis: hypothalamic-pituitary-adrenal axis; Star protein: steroid acute regulatory protein; Dmac2l: distal membrane arm assembly complex 2 like; Esr1: estrogen receptor 1; MAPK pathways: mitogen-activated protein kinase pathways; Sos2: SOS Ras/Rho guanine nucleotide exchange factor 2; Jak2: Janus kinase 2; Pik3cb: phosphatidylinositol-4,5-bisphosphate 3-kinase, and catalytic subunit beta; Kras: KRAS proto-oncogene and GTPase; RRBS: reduced representation bisulfite sequencing; DEGs: differently expressed genes; SPF: Specific Pathogen Free; HE: hematoxylin & eosin; DMR: differentially methylated region; GO Analysis: Gene Ontology analysis; SINE: short interspersed nuclear elements; LINE: long interspersed nuclear elements; LTR: long terminal repeats