宰后牦牛肉细胞凋亡对肌肉内环境与嫩度的影响

摘要

With the aim to explore the effects of apoptosis on muscle internal environment,apoptosis factors and tenderness during postmortem aging,the longissimus dorsi muscles injected with specific inhibitor cyclosporin A (CsA) of MPTP were taken as experiment objects.The muscle internal environment factors,apoptosis factors and tenderness index were measured.The results indicated that myofiber diameter and cross section area in the CsA group were significantly or extremely significantly larger than those in the control group (P ＜0.05,P ＜0.01);after 6 h and 72 ～ 120 h of postmortem,the pH value in the CsA group was lower than that in the control group (P ＜ 0.05),and at 6 ～ 168 h of postmortem,ATP contents in the CsA group were higher than those in control group,specially,after 12 h and 72 ～ 168 h of postmortem,ATP contents in the two groups had significant difference (P ＜ 0.05);the degree of MPTP opening in the CsA group was lower than that in the control group (P ＜ 0.01);Cyt-c content in the cytoplasm was significantly or extremely significantly lower in the early aging stage,and the result was opposite in the late aging time;caspase-3 activities in the CsA group was lower than those in the control group during the whole time except after 72 ～ 120 h of postmortem;Hsp27 expression in the CsA group was lower than that in the control group,after 12 ～24 h of postmortem,the shear force of the CsA group was higher compared with the control group.Cyclosporin A could suppress the changes of internal environment,caspase-3 activities,Hsp27 expression level and the shear force and changes of myofibrils and mitochondrial ultrastructure by suppressing the opening of MPTP,the apoptotic process played a significant role in the changes of internal environment and yak meat tenderness during postmortem aging and the changes of internal environment and tenderness could be adjusted by controlling the apoptosis process.%为探究牦牛肉宰后成熟过程中细胞凋亡对肌肉内环境、细胞凋亡因子及嫩度的影响,以经环孢菌素A(CsA)处理的牦牛背最长肌为研究对象,测定了成熟过程中肌肉内环境指标、凋亡因子及嫩度指标的变化.结果表明,24 ～ 120 h时间内,CsA组肌纤维直径和肌纤维横截面积均显著(P＜0.05)或极显著(P＜0.01)大于对照组;宰后6h、72 ～ 120 h,CsA组pH值显著低于对照组(P＜0.05),宰后6～168 h,CsA组ATP含量均高于对照组,且在宰后12h、72 ～ 168 h两者之间ATP含量存在显著差异(Jp＜0.05);成熟过程中CsA组MPTP开放程度极显著低于对照组(P＜0.01);成熟前期CsA组胞浆中Cyt-c浓度显著或极显著低于对照组,成熟后期CsA组胞浆中Cyt-c浓度显著或极显著高于对照组;在整个成熟过程中(除72 ～ 120 h),CsA组caspase-3活性均显著或极显著低于对照组,CsA组Hsp27表达量均显著或极显著低于对照组;12 ～24 h,CsA组剪切力显著(P＜0.05)或极显著(P＜0.01)高于对照组.表明CsA能够通过抑制MPTP的开放而抑制细胞凋亡的发生并影响肌肉内环境、caspase-3活性、Hsp27表达,剪切力及肌原纤维微观结构的变化,说明细胞凋亡的发生对肌肉内环境变化及宰后牦牛肉嫩化具有重要影响,且可以通过控制宰后肌肉细胞凋亡发生进程来调节肌肉内环境变化及肌肉嫩化程度.