Peripheral oxygen transport and utilization in rats following continued selective breeding for endurance running capacity
Peripheral oxygen transport and utilization in rats following continued selective breeding for endurance running capacity
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DOI：
10.1152/japplphysiol.00914.2007
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发表时间：
2009-06-01
影响因子：
3.3
通讯作者：
Wagner, Peter D.
中科院分区：
文献类型：
--
作者：
Howlett, Richard A.;Kirkton, Scott D.;Wagner, Peter D.
Howlett RA, Kirkton SD, Gonzalez NC, Wagner HE, Britton SL, Koch LG, Wagner PD。持续选择性饲养大鼠耐力跑能力后外周氧运输和利用。中国生物医学工程学报（英文版），2009,31(2):444 - 444。首次发表于2008年4月17日；doi: 10.1152 / japplphysiol.00914.2007。-未经训练的大鼠选择性饲养高（HCR）或低（LCR）跑步机跑步能力，早在第七代（G7）就表现出不同的生理特征。我们想知道继续选择性繁殖到第15代（G15）是否会进一步增加骨骼肌毛细血管、形态测定和氧化能力的差异，这些差异在之前的G7中已经看到。在G15时，HCR大鼠的平均体重（n = 11; 194 +/- 3 g）显著低于LCR大鼠（n = 12; 259 +/- 9 g），而相对腓肠肌内侧肌肉质量无差异（0.23 +/- 0.01 vs. 0.22 +/- 0.01%总体重）。尽管绝对肌肉质量较低，但在HCR中，常氧（FIO2 = 0.21） (V)比dotO（2max）高50% (P < 0.001)，骨骼肌O-2电导（在缺氧时测量，FIO2 = 0.10）在HCR中高49% （P < 0.001）。HCR组肌肉氧化酶活性显著提高(柠檬酸合成酶：16.4 +/- 0.4 vs. 14.0 +/- 0.6； β -羟酰基辅酶a脱氢酶：5.2 +/- 0.2 vs. 4.2 +/- 0.2 mmol.kg（-1).min(-1)）。HCR大鼠的总肌纤维增加了36%，内侧腓肠肌的毛细血管增加了36%。由于平均肌纤维面积小35%，HCR组毛细血管密度高36%，但毛细血管/纤维比相同。与G7相比，G15 HCR动物的总纤维数量增加了38%，平均纤维面积减少了25%。这些数据表明，许多骨骼肌结构和功能的适应，使七岁时HCR中O-2的利用率更高，在耐力能力的额外选择性育种后，继续取得进展。然而，G15的最大变化与O-2向骨骼肌的输送有关，而与骨骼肌使用O-2的能力无关。
Howlett RA, Kirkton SD, Gonzalez NC, Wagner HE, Britton SL, Koch LG, Wagner PD. Peripheral oxygen transport and utilization in rats following continued selective breeding for endurance running capacity. J Appl Physiol 106: 1819-1825, 2009. First published April 17, 2008; doi:10.1152/japplphysiol.00914.2007.-Untrained rats selectively bred for either high (HCR) or low (LCR) treadmill running capacity previously demonstrated divergent physiological traits as early as the seventh generation (G7). We asked whether continued selective breeding to generation 15 (G15) would further increase the divergence in skeletal muscle capillarity, morphometry, and oxidative capacity seen previously at G7. At G15, mean body weight was significantly lower (P < 0.001) in the HCR rats (n = 11; 194 +/- 3 g) than in LCR (n = 12; 259 +/- 9 g) while relative medial gastrocnemius muscle mass was not different (0.23 +/- 0.01 vs. 0.22 +/- 0.01% total body weight). Normoxic (FIO2 = 0.21) (V) over dotO(2max) was 50% greater (P < 0.001) in HCR despite the lower absolute muscle mass, and skeletal muscle O-2 conductance (measured in hypoxia; FIO2 = 0.10) was 49% higher in HCR (P < 0.001). Muscle oxidative enzyme activities were significantly higher in HCR (citrate synthase: 16.4 +/- 0.4 vs. 14.0 +/- 0.6; beta-hydroxyacyl-CoA dehydrogenase: 5.2 +/- 0.2 vs. 4.2 +/- 0.2 mmol.kg(-1).min(-1)). HCR rats had similar to 36% more total muscle fibers and also 36% more capillaries in the medial gastrocnemius. Because average muscle fiber area was 35% smaller, capillary density was 36% higher in HCR, but capillary-to-fiber ratio was the same. Compared with G7, G15 HCR animals showed 38% greater total fiber number with an additional 25% decrease in mean fiber area. These data suggest that many of the skeletal muscle structural and functional adaptations enabling greater O-2 utilization in HCR at G7 continue to progress following additional selective breeding for endurance capacity. However, the largest changes at G15 relate to O-2 delivery to skeletal muscle and not to the capacity of skeletal muscle to use O-2.