Capillary Supply and Fiber Morphometry in Rat Myocardium after Intermittent Exposure to Hypobaric Hypoxia

Panisello, Pere; Torrella, Joan Ramón; Pagés, Teresa; Viscor, Ginés

doi:10.1089/ham.2007.1030

Cited by 22 publications

(20 citation statements)

References 34 publications

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“…Previous work on myocardium muscle showed a progressive increase from C to H to P20 in capillary and Wbre densities associated with signiWcant reductions in Wbre area, perimeter and diVusion distances (Panisello et al 2007). Those results contrast with the results obtained in the present study due to the diVerent oxidative demands of the three muscles (myocardium, TA and DG) considered.…”

Section: Hypoxia and Muscle Workloadcontrasting

confidence: 99%

“…With this approach in mind, we developed animal experiments using techniques and methods that cannot be used on humans for ethical or technical reasons. In a recent work we applied an IHHE protocol to laboratory rats in order to study myocardial morphofunctional parameters (Panisello et al 2007). Our Wndings indicate that the programme induces an adaptive response in rat myocardium for more eYcient O 2 delivery to the mitochondria of cardiac muscle cells.…”

Section: Introductionmentioning

confidence: 99%

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Capillary supply, fibre types and fibre morphometry in rat tibialis anterior and diaphragm muscles after intermittent exposure to hypobaric hypoxia

et al. 2008

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Three groups of sedentary male rats were exposed to intermittent hypobaric hypoxia (IHH) for 22 days (4 h/day, 5 days/week) in a hypobaric chamber at a simulated altitude of 5,000 m. Tibialis anterior (TA) and diaphragm (DG) were removed at the end of the programme (H group), and 20 or 40 days later (P20 and P40 groups). A control group (C) was maintained at sea-level pressure and their TA and DG were compared to those of the experimental rats at the end of the IHH programme, and also 20 and 40 days later. We measured the fibre morphometry and capillaries of each muscle. Our results demonstrate that IHH does not change the fibre type composition (with reference to either their contractile or oxidative properties) for most muscle regions of the muscles analysed analysed. We found few significant differences in muscle capillarity and fibre morphometry for TA after IHH. However, IHH did induce some statistically significant changes in DG: capillary density of the H rats (736 capillaries/mm2) increased compared to C animals (610 capillaries/mm2). Although IHH did not change the fibre capillarization or morphometric parameters of fast fibre types, we observed reductions ranging from 7 to 13% in fibre area, perimeter and diffusion distances between C and H for slow fibres. Moreover, these morphometric changes accounted for increases of 10-20% in capillarization, fibre unit area and fibre unit perimeter. This indicates that SO fibres are more sensitive to IHH than both fast fibre types.

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Section: Hypoxia and Muscle Workloadcontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Capillary supply, fibre types and fibre morphometry in rat tibialis anterior and diaphragm muscles after intermittent exposure to hypobaric hypoxia

et al. 2008

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“…A clear diminution of soleus muscle capillarization was observed, accompanied by a similar, but less marked, trend in extensor digitorum longus muscle. This decrease in the number of capillaries per mm 2 in both muscles does not agree with the findings of most studies on hypoxia effects (Valdivia, 1958;Banchero, 1975;Banchero et al 1976), including studies previously undertaken in our laboratory (Panisello et al 2007). However, the present results are in partial agreement with the few studies on anaemia and capillary density (Celsing et al 1988).…”

Section: Discussioncontrasting

confidence: 85%

Morphofunctional responses to anaemia in rat skeletal muscle

et al. 2008

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Adult male Sprague-Dawley rats were randomly assigned to two groups: control and anaemic. Anaemia was induced by periodical blood withdrawal. Extensor digitorum longus and soleus muscles were excised under pentobarbital sodium total anaesthesia and processed for transmission electron microscopy, histochemical and biochemical analyses. Mitochondrial volume was determined by transmission electron microscopy in three different regions of each muscle fibre: pericapillary, sarcolemmal and sarcoplasmatic. Muscle samples sections were also stained with histochemical methods (SDH and m-ATPase) to reveal the oxidative capacity and shortening velocity of each muscle fibre. Determinations of fibre and capillary densities and fibre type composition were made from micrographs of different fixed fields selected in the equatorial region of each rat muscle. Determination of metabolites (ATP, inorganic phosphate, creatine, creatine phosphate and lactate) was done using established enzymatic methods and spectrophotometric detection. Significant differences in mitochondrial volumes were found between pericapillary, sarcolemmal and sarcoplasmic regions when data from animal groups were tested independently. Moreover, it was verified that anaemic rats had significantly lower values than control animals in all the sampled regions of both muscles. These changes were associated with a significantly higher proportion of fast fibres in anaemic rat soleus muscles (slow oxidative group = 63.8%; fast glycolytic group = 8.2%; fast oxidative glycolytic group = 27.4%) than in the controls (slow oxidative group = 79.0%; fast glycolytic group = 3.9%; fast oxidative glycolytic group = 17.1%). No significant changes were detected in the extensor digitorum longus muscle. A significant increase was found in metabolite concentration in both the extensor digitorum longus and soleus muscles of the anaemic animals as compared to the control group. In conclusion, hypoxaemic hypoxia causes a reduction in mitochondrial volumes of pericapillary, sarcolemmal, and sarcoplasmic regions. However, a common proportional pattern of the zonal distribution of mitochondria was maintained within the fibres. A significant increment was found in the concentration of some metabolites and in the proportion of fast fibres in the more oxidative soleus muscle in contrast to the predominantly anaerobic extensor digitorum longus.

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“…Michel et al [26] reported a relationship of 1 capillary to 4 cardiomyocytes in domestic chickens, 1:6 in domestic ducks and 1:9 in pheasants. In the mammalian heart the number of capillaries per mm 2 was reported as about 2000–4000 in the human [27, 28] and rat [29, 30], 5000 capillaries in sheep [31] and 2500 in the Yak [32]. These results indicate the large range of these allied parameters among different species.…”

Section: Discussionmentioning

confidence: 99%

Comparative Quantitative Studies on the Microvasculature of the Heart of a Highly Selected Meat-Type and a Wild-Type Turkey Line

et al. 2017

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In this study the macroscopic and microscopic structure of the heart of a fast growing, meat-type turkey line (British United turkeys BUT Big 6) and a wild-type turkey line (Canadian Wild turkey) were compared. At 8 and 16 weeks of age, 10 birds of each genotype and sex were sampled. The body mass and heart mass of the meat-type turkey both increased at a faster rate than those of the wild-type turkey. However in both turkey lines, the relative heart mass decreased slightly with age, the decrease was statistically significant only in the male turkeys. Furthermore meat-type turkeys had a significantly (p < 0.01) lower relative heart mass and relative thickness of the left ventricle compared to the wild-type turkeys of the same age. The wild-type turkeys showed no significant change in the size of cardiomyocytes (cross sectional area and diameter) from 8 weeks to 16 weeks. In contrast, the size of cardiomyocytes increased significantly (p < 0.001) with age in the meat-type turkeys. The number of capillaries in the left ventricular wall increased significantly (p < 0.001) in wild-type turkeys from 2351 per mm2 at the age of 8 weeks to 2843 per mm2 at 16 weeks. However, in the meat-type turkeys there were no significant changes, capillary numbers being 2989 per mm2 at age 8 weeks and 2915 per mm2 at age 16 weeks. Correspondingly the area occupied by capillaries in the myocardium increased in wild-type turkeys from 8.59% at the age of 8 weeks to 9.15% at 16 weeks, whereas in meat-type turkeys this area decreased from 10.4% at 8 weeks to 9.95% at 16 weeks. Our results indicate a mismatch in development between body mass and heart mass and a compromised cardiac capillary density and architecture in the meat-type turkeys in comparison to the wild-type turkeys.

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Capillary Supply and Fiber Morphometry in Rat Myocardium after Intermittent Exposure to Hypobaric Hypoxia

Cited by 22 publications

References 34 publications

Capillary supply, fibre types and fibre morphometry in rat tibialis anterior and diaphragm muscles after intermittent exposure to hypobaric hypoxia

Capillary supply, fibre types and fibre morphometry in rat tibialis anterior and diaphragm muscles after intermittent exposure to hypobaric hypoxia

Morphofunctional responses to anaemia in rat skeletal muscle

Comparative Quantitative Studies on the Microvasculature of the Heart of a Highly Selected Meat-Type and a Wild-Type Turkey Line

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