Dietary Supplementation with <i>N</i> -Acetylcysteine Ameliorates Sleep Deprivation-Induced Ruminal Apoptosis in Tibetan Sheep

Sleep deprivation (SD) is associated with gastrointestinal dysfunction. However, the mechanisms underlying SD-induced ruminal epithelial apoptosis remain elusive. This study revealed that N-acetylcysteine (NAC), a naturally occurring antioxidant in Allium plants with antioxidant properties, ameliorates SD-induced ruminal microbiota dysbiosis, lipopolysaccharide (LPS) leakage, and apoptosis in sheep. Concurrently, NAC increased the ruminal levels of anti-inflammatory and antioxidant metabolites while reducing proapoptotic metabolite levels. Using a machine learning-based approach, we identified KRT8 as a candidate target gene associated with limited LPS/TLR4-triggered inflammatory responses. Mechanistically, in vitro experiments demonstrated that NAC upregulated KRT8 expression in LPS-induced ruminal epithelial cell inflammatory models and mitigated reactive oxygen species accumulation, inflammatory responses, and apoptosis, whereas KRT8 knockdown abolished the aforementioned protective effects of NAC. These findings suggest that KRT8 may become a potential therapeutic target for sleep disorder-related ruminal pathologies and demonstrate that NAC exerts its protective effect by modulating ruminal microbiota, metabolites, and KRT8.