Effect of NO-mediated Hypoxic Factor-1α Activation on Glycolysis and Tenderness of Postmortem Yak Muscle
Nan Sun
2024, 45(5):
0-0.
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To investigate the effects of Nitric oxide (NO)-mediated hypoxia-inducible factor-1α (HIF-1α) on glycolysis and tenderness of postmortem yak muscle and its regulatory mechanism. In this study, the yak longissimus dorsi was injected with 0.9% saline (control), 200 μmol/L S-nitrosoglutathione (GSNO), 200 μmol/L GSNO + 100 μmol/L YC-1 (HIF-1α inhibitor), and NO levels, HIF-1α, mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway activation, glycolysis-related enzyme activity, and shear force of muscle were analyzed at indicated timepoints (3, 6, 9, 12, 24, and 72 h). The results revealed that NO levels of the GSNO group were significantly higher than those in the control group during 3-72 h (P<0.05), reaching a peak at 6 h.,ERK 1/2 and p-ERK 1/2 expression levels were higher in the GSNO group than the control and GSNO+PD98059 (ERK inhibitor) groups during 3-72 h (P<0.05), reaching a peak at 24 h; during 3-72 h. HIF-1α expression levels were significantly higher in the GSNO group than in the control and GSNO+YC-1 groups (P<0.05), peaking at 12 h. Hexokinase (HK), pyruvate kinase (PK) and lactate dehydrogenase (LDH) reached their maximum values at 9, 12 and 12 h, respectively in the GSNO group (P<0.05) and were significantly higher than in the control group; at 3, 12 and 72 h, the glycolytic potential of the GSNO group was significantly higher than in the other two groups (P<0.05); at 6, 9 and 72 h, the pH value of the GSNO group was significantly lower than those in the other groups (P<0.05); In addition, shear force and HE staining were used to assess the tenderness of the yaks. Shear force, myofiber area and diameter were lower in the GSNO group than in the other groups, and myofiber space was higher in the GSNO group than in the other groups. In conclusion, during the early postmortem aging, NO-mediates HIF-1α expression levels, thereby activating the MAPK/ERK pathway and upregulating HK, PK and LDH activity, accelerating the rate of glycolysis of postmortem yak meat and speeding up pH within the normal range, further improving the tenderness of yak meat. The results of this study may serve as an potential regulatory mechanism regulating the tenderness of yak muscle and provide a reference for improving the theoretical system of glycolysis and tenderness during postmortem aging.