能量负平衡是奶牛酮病的病理学基础，非酯化脂肪酸（NEFA）和β-羟丁酸（BHBA）是能量负平衡条件下机体产生的重要内生性信号分子；泌乳初期奶牛肝脏存在明显的未折叠蛋白应答（UPR），其有可能参与能量代谢障碍性疾病的病理学过程。本项目以NEFA可介导奶牛肝细胞UPR，且BHBA能通过缓解UPR参与机体代谢适应性调节的事实为依据，提出NEFA介导肝细胞UPR促发奶牛酮病，而BHBA通过参与UPR过程影响奶牛酮病发生发展的理论假设。通过不同类型奶牛酮病的体内实验，结合体外培养奶牛肝细胞添加NEFA和BHBA实验，分别构建重组腺病毒载体过表达和沉默PERK、IRE1和ATF6，并分别转染上述腺病毒，检测肝脂代谢和UPR关键分子变化，明确NEFA和BHBA可介导UPR调控奶牛肝脂代谢，探究BHBA通过参与NEFA介导的UPR过程影响奶牛酮病发生发展的作用机制，为探索奶牛酮病防治的新途径提供理论支持。

Negative energy balance (NEB) is considered as the pathological basis of ketosis in dairy cows, and non-esterified fatty acids (NEFA) and β-hydroxybutyric acid (BHBA) are the important endogenous signal molecules produced by the body under the condition of NEB. Studies have shown that livers of early lactation cows emerge the obvious unfolded protein response (UPR), which may participate in the pathological process of energy metabolism disorders. On the basis of the facts that NEFA could mediate the hepatocyte UPR of dairy cows and BHBA involves in the metabolic adaptive adjustment through reducing UPR, we hypothesize that NEFA mediates hepatocyte UPR thus contributing to the ketosis in dairy cows, while BHBA could influence the occurrence and development of ketosis in dairy cows via participating in the UPR process. In vivo, dairy cows with ketosis were used as animal model. In vitro, the bovine hepatocytes were cultured and treated with varied concentrations of NEFA and/or BHBA, and transfected with overexpression or silencing of PERK, IRE1 and ATF6 adenovirus, respectively. The key molecules in the hepatic lipid metabolism and UPR signaling pathway were measured to make clear the NEFA- and BHBA-mediated the regulation of UPR on lipid metabolism of dairy cows, which will explore the signaling mechanism of the occurrence and development of ketosis in dairy cows affected by BHBA participating in the NEFA-mediated UPR process. The present study will provide theoretical basis for searching new approach for preventing of ketosis in dairy cows.