Blood Transcriptome Analysis Reveals Immune Characteristics of Captive Forest Musk Deer (Moschus berezovskii) at High Altitude in Bianba County, Tibet

The hypoxic, cold, and high-ultraviolet radiation environments at high altitude pose severe challenges to mammalian immune and metabolic systems. However, little is known about how captive forest musk deer adapt to high-altitude environments and their seasonal variations. This study analyzed peripheral blood transcriptomes of 33 captive forest musk deer (<i>Moschus berezovskii</i>) at high altitude (~3900 m) and low altitude (~1450 m) during autumn-winter and spring-summer seasons. Results revealed comprehensive immune suppression in the high-altitude group during autumn-winter (downregulation of complement system <i>CFB</i>/<i>C2</i>/<i>C3</i>, interferon pathway genes including <i>FLT3</i>, with only natural killer (NK) cell <i>PRKCQ</i> upregulated), coupled with energy-conserving metabolic reprogramming (altered carbohydrate metabolism, inhibited lipid synthesis, fat mobilization, suppressed protein degradation). During spring-summer, neutrophil antimicrobial responses (<i>SLPI</i>/<i>NCF1</i>/<i>ELANE</i>) and humoral immunity (B cell differentiation genes <i>PAX5</i>/<i>RUNX1</i>; class-switch enzyme <i>AICDA</i>) partially recovered while cellular immunity (<i>IL15</i>/<i>B2M</i>) remained suppressed, accompanied by enhanced anabolic metabolism and adipocyte differentiation. Notably, NK cell-mediated cytotoxicity showed selective enhancement despite comprehensive immune suppression, representing an energy-efficient innate defense strategy. This study provides the first characterization of seasonal immune dynamics in a high-altitude cervid species. These findings reveal persistent immune constraints in high-altitude populations and provide theoretical foundations for disease prevention and health management in captive forest musk deer at high altitudes.