Single-cell analysis of adult mouse testes exposed to cigarette smoke.

BACKGROUND

Smoking is a significant global public health concern that has been shown to cause damage to testicular tissue and impair the entire process of spermatogenesis.

METHODS

A passive smoking mouse model was established to investigate the effects of cigarette smoke exposure. The study included measurements of body weight and testicular weight, pathological assessment of testicular damage, apoptosis experiments, and single-cell RNA sequencing (scRNA-seq) to analyze transcriptomic changes. Additionally, differentially expressed genes were examined, along with gene ontology (GO) analysis and gene set enrichment analysis (GSEA).

RESULTS

Both testicular weight (control: 126.90 ± 8.26; smoking: 111.60 ± 6.91; P 0.05) and body weight (control: 37.10 ± 1.55; smoking: 27.73 ± 1.20; P 0.0001) were significantly reduced in the smoking group, while the organ coefficient increased significantly (control: 3.31 ± 0.33; smoking: 4.14 ± 0.47; P 0.001). Smoking markedly increased the proportion of apoptotic cells in testicular tissue (control: 0.24 ± 0.08; smoking: 1.06 ± 0.20; P 0.001). ScRNA-seq revealed time-dependent alterations in the proportions of various testicular cell types due to smoking. Smoking affected cytoskeleton and microtubule formation in multiple cell types, as well as flagella development during spermatogenesis. Smoking induced apoptosis across several testicular cell types and disrupted exocrine functions. Mitochondrial energy metabolism was also impaired in multiple cell types. GSEA further supported the induction of apoptosis in various testicular cells.

CONCLUSION

Smoking significantly impairs testicular structure and spermatogenesis through multiple mechanisms, including induction of apoptosis, disruption of cellular structure and flagella formation, alteration of exocrine function, and impairment of mitochondrial energy metabolism. These findings highlight the detrimental effects of smoking on male reproductive health at the cellular and molecular levels.