Biological effects of baicalin on the ovine mammary cells and regulatory mechanism study by transcriptomic analysis

Baicalin is a natural flavonoid compound with a wide range of biological activities, including anti-oxidant and anti-inflammatory properties. Previous we found that the abundance of baicalin in bovine serum is significantly higher than in ovine serum at mid-lactation. It suggests that baicalin may play a role in the regulation of lactation performance. Here, the biological effects of baicalin on proliferative, oxidative stress response, synthesis capacities of major milk components of ovine mammary epithelial cells (OMECs) were investigated. And the transcriptomic analysis was utilized to explore the possible regulatory mechanism. Results showed that 25 μg/mL baicalin can significantly enhance the proliferation, antioxidant, triglyceride and lactose synthesis capacities of OMECs. In transcriptomic analysis, 150 differentially expressed genes (DEGs) were screened between 25 μM baicalin treated (Baicalin) and 0 μM baicalin treated (NT) groups. Functional analysis of DEGs showed that lipid metabolic process, response to oxidative stress, biosynthesis of fat and saccharide pathways were enriched. qRT-PCR result showed that antioxidation-related negative regulatory gene MPO was significantly down-regulated and milk fat biosynthesis related genes PLA2G12A, GPCPD1, LPIN1, FASN and lactose biosynthesis related genes MGEA5, RHOQ were significantly up-regulated in baicalin treated OMECs (P < 0.01). In summarize, 25 μM baicalin can significantly enhance the proliferation, antioxidant and biosynthesis of milk fat and lactose capacities through lipid metabolic process, response to oxidative stress, biosynthesis of fat and saccharide pathways related genes regulation in OMECs. The study would provide a theoretical basis for the improvement of lactation performance and the exploration of lactation regulation theory of dairy sheep.