递增负荷低氧训练对大鼠股外肌eNOS、HO-1、VEGF mRNA表达的影响

目的:探讨递增负荷低氧训练对调节大鼠骨骼肌血管生长和舒张相关基因(eNOS、HO-1、VEGF)的影响。方法:80只雄性SD大鼠适应性训练后分为常氧安静组,常氧训练组,常氧递增训练Ⅰ、Ⅱ组,低氧安静组,低氧训练组,低氧递增训练Ⅰ、Ⅱ组,共8组;所有训练组进行4周水平跑台训练,常氧训练组(35m/min)和低氧训练组(30m/min)采用恒定负荷,1h/d,5d/w,持续4周;4个递增训练组采用递增负荷,1h/d,5d/w,持续4周。低氧组每天在低氧环境(氧浓度13.6%,模拟海拔约3500米)中生活。采用荧光定量PCR测定股外肌eNOS、HO-1、VEGF mRNA表达。结果:(1)低氧训练组骨骼肌eNOS mRNA表达较常氧安静、常氧训练和低氧安静组显著下降(P<0.05),常氧递增训练Ⅱ组较常氧训练组显著上升(P<0.01),低氧递增训练Ⅱ组较低氧训练、低氧递增训练Ⅰ组均显著下降(P<0.05)。(2)常氧训练、低氧训练组骨骼肌HO-1 mRNA表达较常氧安静和低氧安静组均显著下降(P<0.05),常氧递增训练I组较常氧训练组显著上升(P<0.05),低氧递增训练Ⅱ组较低氧训练和低氧递增训练Ⅰ组显著性下降。(3)常氧训练、低氧训练组骨骼肌VEGF mRNA表达较常氧安静组显著上升(P<0.01),低氧递增训练Ⅱ组较常氧递增训练Ⅱ、低氧训练、低氧递增训练Ⅰ组均显著降低。结论:(1)低氧环境长期训练抑制股外肌eNOS mRNA表达;一定强度常氧递增训练促进其表达,低氧递增负荷训练则抑制其表达。(2)4周常氧和低氧训练均抑制股外肌HO-1 mRNA表达;低氧和常氧递增负荷对HO-1的影响与对eNOS一致。(3)常氧训练和低氧训练可促进股外肌VEGF mRNA表达,低氧环境下增加训练负荷抑制其表达。

Effects of Hypoxic Training with Increasing Load on the eNOS,HO-1 and VEGF mRNA Expression in Vastus Lateralis of Rats

Objective To evaluate the effects of hypoxic training with progressively increasing load on the genes related to the vascular growth and vasodilation in vastus lateralis of rats.Methods After adaptive training,80 male SD rats were divided into normoxic control group,normoxic training group,normoxic increasing load training groupⅠ,normoxic increasing load training group Ⅱ,hypoxic control group,hypoxic training group,hypoxic increasing load training group Ⅰ,and hypoxic increasing load training group Ⅱ.All training groups underwent 4-week treadmill training without slope.Constant load treadmill exercise was applied to the normoxic training group and hypoxic training group with 35m/min and 30m/min,respectively,1h/d,5d/w,for a total of 4 weeks,while increasing load was applied to the other training groups.All hypoxic traiing groups stayed in the environment with 13.6% oxygen concentration(simulated altitude of 3500m).The nitricoxide synthase(eNOS),haem oxygenase(HO-1)and vascular endothelial growth factor(VEGF)mRNA genes expressions in vastus lateralis were measured by quantitative fluorescent PCR.Results(1)eNOS mRNA expression decreased significantly in hypoxia training group,comparing to the normoxic control group and normoxic training group(P<0.05),and was significantly higher in normoxic increasing load training group Ⅱ than normoxic training group(P <0.01),and significantly decreased in hypoxic increasing load training group Ⅱ,comparing to the hypoxic increasing load training group Ⅱ and hypoxic training group(P <0.05).(2)HO-1 mRNA experssion in normoxic training group and hypoxic training group significantly decreased,comparing to the normoxic control group and hypoxic control group(P <0.05),significantly enhanced in normoxic increasing load training group Ⅰ,comparing to the normoxic training group(P <0.05),and significantly decreased in hypoxic increasing load training group Ⅱ,comparing to the hypoxic training group and hypoxic increasing load training group Ⅰ(.3)VEGF mRNA expression in normoxic training and hypoxic training groups significantly enhanced,comparing to the normoxic control group(P <0.01),and significantly decreased in hypoxic increasing load training group Ⅱ,comparing to the normoxic increasing load training group Ⅱ,hypoxic training group and hypoxic increasing load training group Ⅰ.Conclusion(1) Long-term hypoxic training inhibits the eNOS mRNA gene expression in rat vastus lateralis,and normoxic training with appropreate increasing load can increase the eNOS mRNA gene expression.(2)4-week normoxic and hypoxic training can inhibit the HO-1 mRNA gene expression in rats’vastus lateralis,same as the effect of increasing load normoxic training and hypoxic training.(3)VEGF mRNA gene expression in rats’vastus lateralis can be induced by normoxic and hypoxic training,but inhibited by hypoxic increased load.