| Objective:To evaluate the effects of hypoxic training on skeletal muscle glycolytic enzyme and its transcription activation pathway.Methods:After 3d environment and 2weeks treadmill training adapt,50 male SD rats were selected from 70 and divided into 5 groups randomly:living-low quiet control group(LC), living-low training-low group(LoLo), living-high quiet control group (HC), living-high training-low group (HiLo) and living-high exercise-high training-low (HiHiLo). All living-high groups stayed in the environment with 13.6% oxygen concentration, about altitude of 3500 m, for 12h/day. All training groups underwent treadmill training with 35m/min for 1 hour/day,5days/week,4 weeks(under the condition of not changing the total training time, HiHiLo groups underwent treadmill training with 30m/min for 30min/day,3days/week, and training in the environment with 13.6% oxygen concentration). Gastrocnemius was got after 24h of last training. The activity of HK, PFK, PK and the content of muscle glycogen, pyruvic acid, ATP was detected by colorimetry. Technology of Real Time Quantitative PCR and Western blotting are adopted in order to test the genes expression, protein or phosphorylation level changes of HK, PFK, PK, PI3K, PKB, mTOR, ERK, p38MAPK, JNK, HIF-la, PP2A, Mix and ChREBP.The main results:1. The HK activity of living-high groups were higher than the LC group, but there was no significant difference (P>0.05). The HK protein expression of the HiLo group was significantly lower than other groups (P<0.05 or P<0.01), and the HiHiLo group was significantly higher than the other groups (P<0.05 or P<0.01). The HK gene expression of living-high groups were significantly higher than living-low groups (P<0.05 or P<0.01), and the HiHiLo group was significantly higher than the other groups (P<0.05 or P<0.01).2. The PFK activity of LoLo and HiHiLo group were significantly higher than LC and HC groups (P<0.05). The PFK protein expression of HiLo and HiHiLo groups were significantly lower than LC and HC groups (P<0.05 or P<0.01), and the HiHiLo group significantly lower than the HiLo group (P<0.05). The PFK gene expression of HiLo group was significant higher than the LC, LoLo and HC group (P<0.05 or P<0.01), and HiHiLo group was significant higher than the other groups (P<0.05 or P<0.01).3. The PK activity of living-high groups have no significantly difference each other (P>0.05), but were all significantly lower than living-low groups (P<0.05 or P<0.01). The PK protein expression of HiLo group was significantly higher than the LC group (p<0.05), and the HiHiLo group was significantly higher than the other groups (P<0.05 or P<0.01). The PK gene expression of the HiLo and HiHiLo groups were significantly higher than the other groups (P<0.01).4. The muscle glycogen content of the LC group was significantly lower than the other groups (P<0.05 or P<0.01), and the LoLo group was significantly higher than HiLo and HiHiLo groups (P<0.01). There was no significant difference of pyruvate content between each groups (P>0.05). The ATP content of living-low groups were significantly higher than living-high groups (P<0.01).5. The PI3K protein expression and phosphorylation of the HiLo and HiHiLo groups were significantly higher than the LC group (P<0.05). The PI3K genes expression of the HiLo and HiHiLo groups were significantly higher than the other groups (P<0.05 or P<0.01).6. The PKB protein expression of HC group was significantly higher than the HiHiLo group (P<0.05), and the HiLo group was significantly higher than the LC and HiHiLo groups (P<0.05). The p-PKB expression of living-high groups were significantly higher than living-low groups (P<0.05 or P<0.01). The PKB gene expression of HiLo group was significantly higher than the other groups (P<0.05 or P<0.01), and the HiHiLo group was significantly higher than the LC group but significantly lower than the other groups (P<0.05).7. The mTOR protein expression of living-high groups were significantly lower than the LoLo group (P<0.05). The p-mTOR expression of HiLo and HiHiLo groups were significantly higher than the other groups (P<0.05 or P<0.01), and the HiHiLo group was significantly higher than the HiLo group (P<0.05). The mTOR gene expression of HiLo group was significantly lower than the LC, LoLo and HiHiLo groups (P<0.05), and HiHiLo group was significantly lower than the LoLo group (P<0.05).8. The ERK protein expression of HiLo and HiHiLo groups were significantly higher than the LC group (P<0.05). The p-ERK expression of the HiHiLo group was significantly higher than the LC, HC and HiLo groups (P<0.05 or P<0.01). The ERK gene expression of HiLo and HiHiLo groups were significantly higher than the other groups (P<0.05 or P<0.01).9. The p38MAPK protein expression of HiLo and HiHiLo groups were significantly higher than the LC and HC groups (P<0.05). The p-p38MAPK expression of HiLo and HiHiLo groups were lower than the other groups, but the difference was not statistically significant level (P>0.05). The p38MAPK gene expression of living-high groups were significantly higher than living-low groups (P<0.05 or P<0.01), and HiHiLo group was significantly higher than HC and HiLo groups (P<0.05).10. The JNK protein expression of living-high groups were significantly higher than the LoLo group (P<0.05), and the HiHiLo group was significantly lower than HC and HiLo groups (P<0.05). The p-JNK expression of the the LC group was significantly lower than the other groups (P<0.01). The JNK gene expression of HiHiLo and LoLo were significantly lower than the other groups (P<0.05 or P<0.01), and the HiLo group was significantly higher than the other groups (P<0.01).11. The HIF-1? protein expression of LC group was significantly lower than the other groups (P<0.01), and the HiHiLo group was significantly higher than LoLo and HC group (P<0.05). The HIF-lagene expression of HiLo and HiHiLo groups were significantly higher than the other groups (P<0.01), and the HiHiLo group was significantly higher than the the HiLo group (P<0.05).12. The PP2A protein expression of HiLo and HiHiLo groups were significantly higher than LoLo and HC groups (P<0.05). The p-PP2A expression of HiLo group was significantly higher than LC, LoLo, and HiHiLo groups (P<0.05 or P<0.01), and the HiHiLo group significantly higher than the LoLo group and significantly lower than the HC group (P<0.05). The PP2A gene expression of the HiLo group was significantly higher than the LC, LoLo and HiHiLo groups (P<0.05 or P<0.01), and the HiHiLo group was higher than the LC and significantly lower than the HC group (P<0.05).13. The Mlx protein expression of the HiLo group was significantly lower than the LoLo, HC and HiHiLo groups (P<0.01), and the HiHiLo group was significantly higher than LC group and significantly lower than the LoLo group (P<0.01). The Mix gene expression of HiLo and HiHiLo groups were significantly than the other groups (P<0.01), and the HiHiLo group was significantly higher than the the HiLo group (P<0.05).14. The ChREBP protein expression of the HiLo group was significantly higher than the LoLo and HC groups (P<0.01), and HiHiLo group was significantly higher than the other groups (P<0.01). The ChREBP gene expression of HiLo and HiHiLo groups were significantly higher than the other groups (P<0.01).The main conclusions:1. Hypoxic training can increase rats skeletal muscle glycolytic key enzymes HK, PFK activity and decrease PK activity below quiet condition, is advantageous to the glycolysis level on the whole to maintain a certain balance or steady state.2. Hypoxic training significantly raise HK, PFK, PK gene expression level which suggesting that hypoxic training to increase the level of transcription of the glycolytic key enzyme, which is beneficial to energy mobilization metabolic demand.3. Hypoxic training may through raise the phosphorylation level of PI3K/PKB/mTOR, JNK and ERK to increases skeletal muscle HIF-la gene and protein expression.4. Hypoxic training may through phosphorylation of PP2A and improve Mix gene and protein level be beneficial to the transcriptional activation of ChREBP.5. Hypoxic training through improve HIF-la and ChREBP gene and protein expression levels, promote downstream HK, PFK and PK gene transcriptional activation, thus contributing to the body of the glycolytic pathway function and to meet the needs of the body for energy. |
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