ABSTRACT
Objective To determine the effect of hypoxia conditions on the expression of autophagyrelated genes including P62,LC3 and Beclin-1 in the gastrocnemius muscles of rats with alimentary obesity and the possible mechanism of cellular autophagy induced by hypoxia exercises.Methods The model of rats with alimentary obesity was induced in Sprague-Dawley rats using high-fat diet.Then the obese rats were randomly divided into a control(C) group,a hypoxia-exercises-for-1-week(E1) group,a hypoxia-exercises-for-2-weeks (E2) group,a hypoxia-exercises-for-3-weeks (E3) group and a hypoxia-exercises-for-4-weeks(E4) group,each of 10.The rats were exposed to the environment where the simulated hypoxia was of about 13.6％ oxygen concentration(about the oxygen concentration at an actual altitude of 3,500 m),and underwent treadmill running with the speed at 20 m/min on a slope of 0 gradient every day,five days a week.After the last training,the rats were killed and sampled.The RT-PCR was used to detect the level of P62,LC3 and Beclin-1 mRNA and Western Blotting was conducted to examine the changes of protein P62 and LC3 before and after the intervention.Results Compared with group C,the expression of Beclin-1 mRNA in group E1,E2 and E3 increased significantly(P＜0.05),while the expression of protein Beclin-1 decreased significantly in group E2.The expression of protein Beclin-1 of group E2 and E3 was significantly lower than that of group E4,but there were no significant differences between group E2 and E3.Compared with group C,the relative expression of P62 mRNA in group E1 and E2 increased significantly(P＜0.05,P＜0.01),with that of group E2 significantly higher than group E1 (P＜0.05).Moreover,the relative expression of P62 mRNA in group E3 was significantly lower than that of E2(P＜0.01),and that of group E4 was significantly higher than group C,E1 and E3(P＜0.01).The relative expression of protein P62 in the obese rats in group E3 was significantly higher than that of group E2(P＜0.05).The relative expression of LC3 mRNA in group E2,E3 and E4 was significantly higher than that of group C(P＜0.01).Moreover,there were no significant differences in LC3-Ⅱ/LC3-Ⅰ protein among the five groups.Conclusion Hypoxia exercise can significantly enhance the relative expression of autophagy genes,and promote,to some extent,the autophagy.However,the transcription of autophagy genes does not happen synchronically with the synthesis of autophagy proteins.Moreover,an increase in autophagy in the skeletal muscle can be seen in the first two weeks of hypoxia exercises,followed by a gradual decrease with time prolonged,which may be the result of the gradual adaptation to hypoxia stimulation of the body.
ABSTRACT
Aim To study the effects of HiHi and HiLo on the lipid metabolism in rats through blood lipids and fatty acid oxidation in gastrocnemius of rats. Methods Thirty male SD rats were selected by means of adaptive training, and then divided into 3 groups randomly: living low-training low group (LoLo), living high-training high group (HiHi), and living high-training low group (HiLo). The rats ran on a treadmill 60 min a day at the speed of 35 m/min under normoxic condition or 30 m/min under hypoxic condition (13.6% of ambient FIO_2), 6 days a week for 4 weeks. The samples from blood and gastrocnemius were removed 24 hours after the last training by the end of 4-week experiment. TC, TG, HDL and LDL were tested with a full-automatic biochemical analyzer. LPL, leptin and AD were measured using ELISA. Real-time quantitative PCR was adopted to test the expression of PPARa and CPT-1 mRNA in rats' gastrocnemius. Results Compared to the LoLo, TC and TG decreased significantly (P0.05) and LPL and AD increased significantly (P<0.01) in HiHi.' PPARa mRNA and CPT-1 mRNA expressions in gastrocnemius were significantly higher in HiHi(P<0.05) than in LoLo, and significant descent of HDL(P<0.05) and CPT-1 mRNA expression(P<0.01) revealed in HiLo, as compared to the LoLo. Compared to the HiLo, HDL(P<0.05), and LPL, AD and CPT-1 mRNA expression(P<0.01) enhanced in HiHi. Conclusion (l) HiHi was more superior in regulation of blood lipids than LoLo due to increasing of LPL, and could facilitate fatty acid oxidation because of enhancement of CPT-1 mRNA, AD and PPARa mRNA. (2) Comparing to the normoxic training, HiLo had no beneficial effect on the blood lipid metabolism and decreased the fatty acid oxidation in gastrocnemius.(3 )HiHi was more superior in the effeet of HDL thah HiLo due to increasing of LPL, and could facilitate fatty acid oxidation because of enhancement of AD and CPT-1 mRNA.
ABSTRACT
Objective This paper is aimed to study the effect of endurance training and supplementation of different-dosage L-Arg on skeletal muscle NOS gene expression in rats. Methods We used the reverse transcription polymerase chain reaction technique to measure the NOS gene expression of skeletal muscle in rats. Results Endurance training significantly increase the eNOS (P