Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Key Laboratory of Animal Physiology and Biochemistry, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Phytomedicine. 2024 Dec;135:156056. doi: 10.1016/j.phymed.2024.156056. Epub 2024 Sep 19.
Mitochondria play a crucial role in upholding metabolic homeostasis. Mitochondrial damage closely associated with the pathogenesis of fatty liver hemorrhagic syndrome (FLHS), while mitophagy being among the most effective methods for eliminating the damaged mitochondria. Dioscin, a natural extract, can activate autophagy; however, its effects on FLHS regarding mitophagy regulation remain unelucidated.
We explored the impact of dioscin on FLHS induced by a high-energy and low-protein (HELP) diet in laying hens, mainly focused the protective effects of dioscin on mitochondrial injury.
To investigate the impact of dioscin on fatty liver syndrome in laying hens, we first induced the condition by feeding them a high-energy and low-protein diet. Then, we assessed lipid metabolism-related markers using oil red staining and a commercial detection kit. In addition, the role of dioscin on fatty liver syndrome in laying hens was confirmed by assessing the activation of hepatocyte fat deposition and hepatocyte apoptosis; and the mechanism of dioscin in FLHS was investigated through LMH cell experiment in vitro. Furthermore, CETSA and molecular docking were conducted for additional confirmation.
The results showed that dioscin alleviated mitochondrial damage, relieved the excessive deposition of hepatic lipid droplets and oxidative stress induced by HELP diet in laying hens. Furthermore, dioscin regulated the mitophagy by activating the estrogen receptor α (ERα)/adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling pathway, thus mitigating mitochondria injury and apoptosis in hepatocytes. In addition, we found that dioscin promoted the translocation of nuclear transcription factor into nucleus by activating ERα-AMPK signaling, facilitating autophagic flux in the liver of laying hens and LMH cells. Furthermore, cells pretreated with the lysosomal acidification inhibitor bafilomycin A1 blocked the inhibitory effect of dioscin on the apoptosis induced by palmitic acid (PA)-stimulation in LMH cells, suggesting that dioscin reduces PA-induced apoptosis by activating mitophagy. Moreover, dioscin-induced lysosomal acidification and mitochondrial biogenesis were reversed in PA-induced LMH cells pretreated with ERα-specific inhibitor methylpiperidino pyrazole.
This study firstly demonstrated that dioscin alleviates fatty liver syndrome induced by HELP diet in laying hens. The findings from this study illustrated that dioscin plays a significant role in reducing mitochondrial damage and apoptosis, and these beneficial effects mainly achieve through promotion of ERα-AMPK signaling, which mediates autophagy within the liver of laying hens fed a HELP-diets. These findings provide a theoretical basis for considering dioscin as a possible treatment option for mitigating FLHS in egg-laying hens.
线粒体在维持代谢稳态方面起着至关重要的作用。线粒体损伤与脂肪肝出血综合征（FLHS）的发病机制密切相关，而自噬是消除受损线粒体最有效的方法之一。薯蓣皂苷元是一种天然提取物，可激活自噬，但它在调节 FLHS 中的作用尚不清楚。
本研究旨在探讨薯蓣皂苷元对高能低蛋白（HELP）饮食诱导的产蛋母鸡 FLHS 的影响，主要关注薯蓣皂苷元对线粒体损伤的保护作用。
为了研究薯蓣皂苷元对产蛋母鸡脂肪肝综合征的影响，我们首先用高能低蛋白饮食诱导母鸡出现这种情况，然后使用油红染色和商业检测试剂盒评估脂质代谢相关标志物。此外，通过评估肝细胞脂肪沉积和肝细胞凋亡的激活，确认薯蓣皂苷元对产蛋母鸡脂肪肝综合征的作用；并通过体外 LMH 细胞实验研究薯蓣皂苷元在 FLHS 中的作用机制。此外，还进行了 CETSA 和分子对接以进行进一步验证。
结果表明，薯蓣皂苷元缓解了 HELP 饮食诱导的产蛋母鸡的线粒体损伤，减轻了肝内脂质滴的过度沉积和氧化应激。此外，薯蓣皂苷元通过激活雌激素受体 α（ERα）/腺苷 5'-单磷酸激活蛋白激酶（AMPK）信号通路调节自噬，从而减轻肝细胞的线粒体损伤和凋亡。此外，我们发现薯蓣皂苷元通过激活 ERα-AMPK 信号转导促进核转录因子向核内易位，促进产蛋母鸡和 LMH 细胞的自噬流。此外，用溶酶体酸化抑制剂巴弗洛霉素 A1 预处理细胞可阻断薯蓣皂苷元对 LMH 细胞中棕榈酸（PA）刺激诱导的凋亡的抑制作用，表明薯蓣皂苷元通过激活自噬来减少 PA 诱导的凋亡。此外，在用 ERα 特异性抑制剂甲基哌啶基吡唑预处理的 PA 诱导的 LMH 细胞中，薯蓣皂苷元诱导的溶酶体酸化和线粒体生物发生被逆转。
本研究首次证明薯蓣皂苷元可减轻高能低蛋白饮食诱导的产蛋母鸡脂肪肝综合征。本研究结果表明，薯蓣皂苷元通过促进 ERα-AMPK 信号转导在产蛋母鸡的肝脏中发挥作用，从而减少线粒体损伤和凋亡，这些有益作用主要通过促进 ERα-AMPK 信号转导介导的自噬来实现。这些发现为将薯蓣皂苷元作为减轻产蛋母鸡 FLHS 的一种可能治疗选择提供了理论依据。
