羊肉成熟中内质网应激介导细胞凋亡的作用机制

After slaughter, the muscles of animal would be in the state of hypoxia ischemia. In addition to apoptosis, it also lead to the phenomenon of endoplasmic reticulum stress in animal cells. The important role of apoptosis on the tenderization of meat has been confirmed. However, the relationship between endoplasmic reticulum stress and the tenderization of meat has not been studied. To solve this issue, skeletal muscle cells of goat are cultured and hypoxia ischemia cell model is made. The effects of factors of endoplasmic reticulum stress during goat postmortem ageing such as PERK, IRE1, ATF6 signaling pathways, Ca2+ homeostasis, as well as related regulatory factors GRP78, CHOP, CRT, JNK, caspase-12, c-Fos, EIK-1, TNF Bim, etc. are investigated, to find out which factors will mainly contribute to goat postmortem ageing. Furthermore, the effects of these factors which were screened out on degradation of myofibril are tested by using inhibitor and activator of endoplasmic reticulum stress. The results of this study will complete the existing mechanism of meat ageing and offer a new insight and theoretical guidance for improving meat quality.

畜禽被屠宰后，肌肉处于缺氧缺血的状态，除细胞凋亡外，还会导致动物体细胞出现内质网应激的现象。细胞凋亡在肉类成熟嫩化中的重要作用已被证实，然而内质网应激与宰后肉的成熟和嫩化之间的关系还未被研究，机制尚不清楚。针对这一改善肉类嫩度品质的关键问题，本项目以羊肉为研究对象，模拟肉类成熟过程建立缺氧缺血的肌细胞模型，研究羊肉成熟过程中内质网应激的PERK、IRE1、ATF6三条信号通路，Ca2+稳态变化，以及相关调控因子GRP78、CHOP、CRT、JNK、caspase-12、c-Fos、EIK-1、TNF、Bim等的调控效应。探究内质网应激介导的肌细胞凋亡过程中促进宰后羊肉成熟的关键信号因子。进一步利用内质网应激的激活剂和抑制剂分析筛选出的信号因子对羊肉肌原纤维降解的影响。项目成果将完善现有的肉类成熟嫩化理论，为改善肉的嫩度提供新的思路和理论指导。

畜禽被屠宰后，肌肉处于缺氧缺血的状态，除细胞凋亡外，还会导致动物体细胞出现内质网应激的现象。利用内质网应激激活剂衣霉素(TM)和抑制剂4-苯基丁酸（4-PBA）处理宰后成熟过程中的肉类，探究内质网应激介导的细胞凋亡信号通路中关键调节因子的变化情况。同时分析这些关键因子对肌原纤维降解的影响。研究发现诱导内质网应激的发生，可以加剧肌原纤维蛋白的水解，进而促进了宰后肉的成熟过程，提高了肉的嫩度。建立缺氧缺血的细胞模型，研究宰后肉成熟过程中肌细胞内质网应激的发生情况。检测 GRP78、CHOP、caspase-12以及内应网应激介导的细胞凋亡下游的信号因子的变化，同时观察肌细胞结构的变化。利用氯化钙、茶多酚、槲皮素处理宰后成熟过程中的肉类，发现内质网应激的相关调控因子GRP78、CHOP、caspase-12、Bim等的活性升高。探究了这三种诱导剂通过内质网应激介导的肌细胞凋亡过程中促进宰后肉类成熟的调控机制。筛选出可以促进肉类肌原纤维降解的诱导剂。本项目一方面利用内质网应激的激活剂和抑制剂，分析筛选出了内质网应激中对肉类肌原纤维降解的影响关键信号因子。另一方面，茶多酚、槲皮素的抗炎、抗肿瘤、抗氧化功能已被熟知，所以利用茶多酚和槲皮素提高宰后肉类嫩度的技术是一种新型的、绿色的食品处理技术，本项目证明了茶多酚和槲皮素技术在提高肉类嫩度方面的积极应用价值，为茶多酚和槲皮素技术在食品加工领域的广泛应用提供了理论支撑。