HIIT与MICT如何改善糖尿病小鼠糖代谢？2024线粒体机制全解析

3. Effects of MICT and HIIT on Glycolytic Metabolism in Skeletal Muscle of db/db Mice (1) MICT and HIIT Increase Glycogen Content in Skeletal Muscle of db/db Mice: PAS staining images revealed that the NC group muscle fibers had densely and uniformly stained deep purple granules. Compared to the NC group, the DC group muscle fibers showed sparse and unevenly distributed deep purple glycogen granules. The HIIT group muscle fibers exhibited densely and uniformly stained granules, similar to the normal group. The staining intensity in the MICT group was intermediate, confirming its partial restorative effect. Statistical analysis of the area of glycogen-positive regions showed that the glycogen content in the DC group mice was significantly lower than that in the NC group (P < 0.001). Compared to the DC group, the glycogen content in both the MICT and HIIT groups was significantly higher (P < 0.001). Compared to the MICT group, the glycogen content in the HIIT group was significantly higher (P < 0.001). (2) MICT and HIIT Improve Glycolytic Metabolism-Related Indicators in Skeletal Muscle of db/db Mice: Compared to the NC group, the protein expression of GLUT4 in the DC group was significantly decreased (P < 0.01). Compared to the DC group, the protein expression of GLUT4 in both the MICT and HIIT groups was significantly increased (P < 0.001). Compared to the MICT group, the protein expression of GLUT4 in the HIIT group was significantly increased (P < 0.001). Compared to the NC group, the L-LDH enzyme activity in the DC group was significantly increased (P < 0.001), while the G6PDH enzyme activity was significantly decreased (P < 0.001). Compared to the DC group, the L-LDH enzyme activity in both the MICT and HIIT groups was significantly decreased (P < 0.05, P < 0.01), and the G6PDH enzyme activity was significantly increased (P < 0.001). Compared to the MICT group, the L-LDH enzyme activity in the HIIT group was significantly decreased (P < 0.001), and the G6PDH enzyme activity was significantly increased (P < 0.05). 4. Regulation of Mitochondrial Quality Control in Skeletal Muscle by MICT and HIIT (1) MICT and HIIT Improve Mitochondrial Quality in Skeletal Muscle of db/db Mice: Electron microscopy showed that mitochondria in the NC group muscle cells were typically ellipsoidal or rod-shaped, arranged tightly and orderly, with clear and complete cristae structures and homogeneous dense matrix. Compared to the NC group, most mitochondria in the DC group were swollen and vacuolated, with disrupted cristae structures and damaged membrane structures. Compared to the DC group, the mitochondrial morphology in both the MICT and HIIT groups was significantly improved, with reduced swelling, partially restored cristae structures, and improved membrane integrity. (2) MICT and HIIT Promote Mitochondrial Biogenesis in Skeletal Muscle of db/db Mice: Compared to the NC group, the protein expression of NRF2 and TFAM in the DC group was significantly decreased (P < 0.01, P < 0.001). Compared to the DC group, the protein expression of NRF2 and TFAM in both the MICT and HIIT groups was significantly increased (P < 0.001). Compared to the MICT group, the protein expression of NRF2 and TFAM in the HIIT group was significantly increased (P < 0.05, P < 0.001). Compared to the NC group, the mtDNA copy number in the DC group was significantly decreased (P < 0.01). Compared to the DC group, the mtDNA copy number in both the MICT and HIIT groups was significantly increased (P < 0.001). Compared to the MICT group, the mtDNA copy number in the HIIT group was significantly increased (P < 0.001). (3) MICT and HIIT Regulate Mitochondrial Dynamics in Skeletal Muscle of db/db Mice: Compared to the NC group, the protein expression of OPA1, MFN2, and DRP1 in the DC group was significantly decreased (P < 0.001). Compared to the DC group, the protein expression of OPA1, MFN2, and DRP1 in both the MICT and HIIT groups was significantly increased (P < 0.001). Compared to the MICT group, the protein expression of OPA1 and DRP1 in the HIIT group was significantly increased (P < 0.01, P < 0.05), while the protein expression of MFN2 showed no significant change. (4) MICT and HIIT Regulate Mitochondrial Autophagy in Skeletal Muscle of db/db Mice: Compared to the NC group, the protein expression of PINK1 and PARKIN in the DC group was significantly decreased (P < 0.001). Compared to the DC group, the protein expression of PINK1 and PARKIN in both the MICT and HIIT groups was significantly increased (P < 0.001). Compared to the MICT group, the protein expression of PINK1 in the HIIT group was significantly increased (P < 0.05), while the protein expression of PARKIN showed no significant change.