Li Long, Cao Heran, Yang Jinmeng, Jin Tianqi, Ma Yuxuan, Wang Yang, Li Zhenpeng, Chen Yining, Gao Huihui, Zhu Chao, Yang Tianhao, Deng Yalong, Yang Fangxia, Dong Wuzi
College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China.
Biology Research Centre of Qin Mountains Wildlife, Northwest A&F University, Yangling 712100, China.
J Zhejiang Univ Sci B. 2023;24(9):807-822. doi: 10.1631/jzus.B2200692.
: The musk glands of adult male Chinese forest musk deer ( Flerov, 1929) (FMD), which are considered as special skin glands, secrete a mixture of sebum, lipids, and proteins into the musk pod. Together, these components form musk, which plays an important role in attracting females during the breeding season. However, the relationship between the musk glands and skin of Chinese FMD remains undiscovered. Here, the musk gland and skin of Chinese FMD were examined using histological analysis and RNA sequencing (RNA-seq), and the expression of key regulatory genes was evaluated to determine whether the musk gland is derived from the skin. : A comparative analysis of musk gland anatomy between juvenile and adult Chinese FMD was conducted. Then, based on the anatomical structure of the musk gland, skin tissues from the abdomen and back as well as musk gland tissues were obtained from three juvenile FMD. These tissues were used for RNA-seq, hematoxylin-eosin (HE) staining, immunohistochemistry (IHC), western blot (WB), and quantitative real-time polymerase chain reaction (qRT-PCR) experiments. : Anatomical analysis showed that only adult male FMD had a complete glandular organ and musk pod, while juvenile FMD did not have any well-developed musk pods. Transcriptomic data revealed that 88.24% of genes were co-expressed in the skin and musk gland tissues. Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analysis found that the genes co-expressed in the abdomen skin, back skin, and musk gland were enriched in biological development, endocrine system, lipid metabolism, and other pathways. Gene Ontology (GO) enrichment analysis indicated that the genes expressed in these tissues were enriched in biological processes such as multicellular development and cell division. Moreover, the Metascape predictive analysis tool demonstrated that genes expressed in musk glands were skin tissue-specific. qRT-PCR and WB revealed that sex-determining region Y-box protein 9 (),Caveolin-1 (), andandrogen receptor () were expressed in all three tissues, although the expression levels differed among the tissues. According to the IHC results, Sox9 and AR were expressed in the nuclei of sebaceous gland, hair follicle, and musk gland cells, whereas Cav-1 was expressed in the cell membrane. : The musk gland of Chinese FMD may be a derivative of skin tissue, and Sox9, Cav-1, and AR may play significant roles in musk gland development.
成年雄性林麝（Flerov，1929）的麝香腺被认为是特殊的皮肤腺体，它将皮脂、脂质和蛋白质的混合物分泌到香囊中。这些成分共同形成麝香，麝香在繁殖季节吸引雌性方面发挥着重要作用。然而，林麝麝香腺与皮肤之间的关系仍未被发现。在此，利用组织学分析和RNA测序（RNA-seq）对林麝的麝香腺和皮肤进行了研究，并评估了关键调控基因的表达，以确定麝香腺是否起源于皮肤。
对幼年和成年林麝的麝香腺解剖结构进行了比较分析。然后，根据麝香腺的解剖结构，从三只幼年林麝身上获取腹部和背部的皮肤组织以及麝香腺组织。这些组织用于RNA-seq、苏木精-伊红（HE）染色、免疫组织化学（IHC）、蛋白质免疫印迹（WB）和定量实时聚合酶链反应（qRT-PCR）实验。
解剖分析表明，只有成年雄性林麝有完整的腺体器官和香囊，而幼年林麝没有任何发育良好的香囊。转录组数据显示，88.24%的基因在皮肤和麝香腺组织中共同表达。京都基因与基因组百科全书（KEGG）信号通路分析发现，在腹部皮肤、背部皮肤和麝香腺中共同表达的基因在生物发育、内分泌系统、脂质代谢等通路中富集。基因本体论（GO）富集分析表明，在这些组织中表达的基因在多细胞发育和细胞分裂等生物学过程中富集。此外，Metascape预测分析工具表明，在麝香腺中表达的基因是皮肤组织特异性的。qRT-PCR和WB结果显示，性别决定区Y框蛋白9（Sox9）、小窝蛋白-1（Cav-1）和雄激素受体（AR）在所有三种组织中均有表达，尽管各组织中的表达水平有所不同。根据免疫组织化学结果，Sox9和AR在皮脂腺、毛囊和麝香腺细胞的细胞核中表达，而Cav-1在细胞膜中表达。
林麝的麝香腺可能是皮肤组织的衍生物，Sox9、Cav-1和AR可能在麝香腺发育中发挥重要作用。
