scholarly journals Fiber Type Distribution, Cross-Sectional Area, and Succinate Dehydrogenase Activity of Soleus and Extensor Digitorum Longus Muscles in Spontaneously Hypertensive Rats

2002 ◽  
Vol 35 (4) ◽  
pp. 315-322 ◽  
Author(s):  
Toshiaki Nakatani ◽  
Toshikatsu Nakashima ◽  
Taizo Kita ◽  
Chiyoko Hirofuji ◽  
Kazuo Itoh ◽  
...  
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Extensor Digitorum Longus ◽  
Fiber Type ◽  
Sectional Area ◽  
Hypertensive Rats ◽  
Succinate Dehydrogenase Activity ◽  
Cross Sectional ◽  
Spontaneously Hypertensive ◽  
Type Distribution ◽  
Fiber Type Distribution

In spontaneously hypertensive rats alterations in aortic wall properties precede development of hypertension

2000 ◽  
Vol 278 (4) ◽  
pp. H1241-H1247 ◽  
Author(s):  
Ad W. van Gorp ◽  
Dorette S. Van Ingen Schenau ◽  
Arnold P. G. Hoeks ◽  
Harry A. J. Struijker Boudier ◽  
Jo G. R. de Mey ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Elastic Modulus ◽  
Spontaneously Hypertensive Rats ◽  
Aortic Wall ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Hypertensive Rats ◽  
Cross Sectional ◽  
Spontaneously Hypertensive ◽  
Wall Properties

In hypertension arterial wall properties do not necessarily depend on increased blood pressure alone. The present study investigates the relationship between the development of hypertension and thoracic aortic wall properties in 1.5-, 3-, and 6-mo-old spontaneously hypertensive rats (SHR); Wistar-Kyoto rats (WKY) served as controls. During ketamine-xylazine anesthesia, compliance and distensibility were assessed by means of a noninvasive ultrasound technique combined with invasive blood pressure measurements. Morphometric measurements provided in vivo media cross-sectional area and thickness, allowing the calculation of the incremental elastic modulus. Extracellular matrix protein contents were determined as well. Blood pressure was not significantly different in 1.5-mo-old SHR and WKY, but compliance and distensibility were significantly lower in SHR. Incremental elastic modulus was not significantly different between SHR and WKY at this age. Media thickness and media cross-sectional area were significantly larger in SHR than in WKY, but there was no consistent difference in collagen density and content between the strains. Blood pressure was significantly higher in 3- and 6-mo-old SHR than in WKY, and compliance was significantly lower in SHR. The findings in this study show that in SHR, in which hypertension develops over weeks, alterations in functional aortic wall properties precede the development of hypertension. The decrease in compliance and distensibility at a young age most likely results from media hypertrophy rather than a change in intrinsic elastic properties.

scholarly journals MyoSight—semi-automated image analysis of skeletal muscle cross sections

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lyle W. Babcock ◽  
Amy D. Hanna ◽  
Nadia H. Agha ◽  
Susan L. Hamilton
Keyword(s):  
Skeletal Muscle ◽  
Image Analysis ◽  
Cross Sections ◽  
Fiber Type ◽  
Sectional Area ◽  
Cross Sectional ◽  
Type Distribution ◽  
Central Nuclei ◽  
Fiber Size ◽  
Fiber Type Distribution

Abstract Background Manual analysis of cross-sectional area, fiber-type distribution, and total and centralized nuclei in skeletal muscle cross sections is tedious and time consuming, necessitating an accurate, automated method of analysis. While several excellent programs are available, our analyses of skeletal muscle disease models suggest the need for additional features and flexibility to adequately describe disease pathology. We introduce a new semi-automated analysis program, MyoSight, which is designed to facilitate image analysis of skeletal muscle cross sections and provide additional flexibility in the analyses. Results We describe staining and imaging methods that generate high-quality images of immunofluorescent-labelled cross sections from mouse skeletal muscle. Using these methods, we can analyze up to 5 different fluorophores in a single image, allowing simultaneous analyses of perinuclei, central nuclei, fiber size, and fiber-type distribution. MyoSight displays high reproducibility among users, and the data generated are in close agreement with data obtained from manual analyses of cross-sectional area (CSA), fiber number, fiber-type distribution, and number and localization of myonuclei. Furthermore, MyoSight clearly delineates changes in these parameters in muscle sections from a mouse model of Duchenne muscular dystrophy (mdx). Conclusions MyoSight is a new program based on an algorithm that can be optimized by the user to obtain highly accurate fiber size, fiber-type identification, and perinuclei and central nuclei per fiber measurements. MyoSight combines features available separately in other programs, is user friendly, and provides visual outputs that allow the user to confirm the accuracy of the analyses and correct any inaccuracies. We present MyoSight as a new program to facilitate the analyses of fiber type and CSA changes arising from injury, disease, exercise, and therapeutic interventions.

Distensibility of the Left Atrial Wall in Spontaneously Hypertensive Rats Compared with That in Normotensive Wistar-Kyoto Rats

1980 ◽  
Vol 59 (s6) ◽  
pp. 361s-363s
Author(s):  
S.-E. Ricksten ◽  
T. Yao ◽  
B. Ljung ◽  
P. Thorean
Keyword(s):  
Left Atrial ◽  
Spontaneously Hypertensive Rats ◽  
Relative Length ◽  
Hypertensive Rats ◽  
Atrial Wall ◽  
Cross Sectional ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto Rats ◽  
Left Atrial Wall ◽  
Wistar Kyoto

1. The cardiac mechanoreceptors, which in rats are mainly located in the left atrial wall, are reset in spontaneously hypertensive rats. The atrial pressure has to be almost twice as high in spontaneously hypertensive rats as in normotensive controls to produce similar receptor activations, as is apparent from previous studies. 2. The present study was performed to investigate whether this resetting is due to decreased distensibility of left atrial walls in the spontaneously hypertensive rats. 3. Static load-length relationships were investigated in vitro on left atrial strips, and pressure-volume relationships were studied on isolated left atria from spontaneously hypertensive and normotensive Wistar-Kyoto rats. 4. The force per cross-sectional area exerted during a relative length increase of 80% was significantly greater in spontaneously hypertensive rats. The dynamic but not the static distensibility was significantly lower in these animals. 5. The decreased dynamic distensibility of left atrial walls in spontaneously hypertensive rats can at least partly explain the resetting of atrial receptor function.

Histochemical fiber type distribution and epinephrine sensitivity in normal and cross-transplanted rat muscles

1987 ◽  
Vol 65 (6) ◽  
pp. 1205-1212 ◽  
Author(s):  
John M. Kennedy ◽  
Franz S. F. Mong ◽  
James L. Poland
Keyword(s):  
Soleus Muscle ◽  
Extensor Digitorum Longus ◽  
Fiber Type ◽  
Extensor Digitorum ◽  
Glycogen Depletion ◽  
Type Distribution ◽  
Control Muscle ◽  
Glycogen Concentration ◽  
Fiber Type Distribution ◽  
Epinephrine Dose

The metabolic integrity of fully regenerated transplants was investigated by measuring induced changes in glycogen concentration. The extensor digitorum longus and the soleus muscles were cross transplanted: the extensor digitorum longus into the soleus muscle bed (SOLT) and the soleus muscle into the extensor digitorum longus bed (EDLT). The histochemical fiber type distribution of the regenerated muscles was determined and was found to transform in cross-transplanted EDLT and SOLT. After transplantation and regeneration, both muscles had initially low glycogen concentrations. However, the EDLT glycogen concentration was not significantly different from that of the contralateral extensor digitoium longus control muscle after 60 days. In the SOLT, glycogen gradually increased but remained less than in the contralateral soleus control muscle. SOLT and control soleus muscles responded with a significant glycogen depletion to an epinephrine dose two orders of magnitude less than the lowest dose affecting glycogen levels in EDLT and extensor digitorum longus muscles. These results indicate that transplanted muscles are capable of regenerating normal glycogenolytic responses and that the sensitivity of the response observed depends on the site of transplantation and is related to the type of innervation and histochemical fiber type.

Role of protein intake on protein synthesis and fiber distribution in the unweighted soleus muscle

1993 ◽  
Vol 75 (3) ◽  
pp. 1226-1232 ◽  
Author(s):  
D. Taillandier ◽  
X. Bigard ◽  
D. Desplanches ◽  
D. Attaix ◽  
C. Y. Guezennec ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Soleus Muscle ◽  
Protein Intake ◽  
Fiber Type ◽  
Weight Bearing ◽  
Type I ◽  
Fiber Distribution ◽  
Cross Sectional ◽  
Type Distribution ◽  
Fiber Type Distribution

Protein turnover in skeletal muscle is very sensitive to protein intake. To examine whether protein intake is able to affect protein synthesis in the atrophied soleus muscle, the effects of a high-protein (30%, HP) and a medium-protein (15%, MP) diet were studied in rats after 21 days of hindlimb unweighting. Three weeks of unweighting induced a sharp decrease in food intake (30%). The fractional rate of protein synthesis (ks) was determined in vivo in the slow-twitch soleus muscle by use of a flooding-dose method. With respect to pair-fed animals, a significant reduction in ks occurred (33%) in MP non-weight-bearing rats, whereas it was of lesser magnitude and not significant in HP rats. In the atrophied soleus muscle of non-weight-bearing MP rats, a large decrease (42%) in type I fiber distribution was accompanied by an increase in intermediate and type IIa fibers. By contrast, a higher percentage of type I fiber was maintained with the HP diet. However, the HP diet had no beneficial effect in preventing the decrease in either type I fiber cross-sectional area (65%) or the average decrease in absolute myofibrillar and mitochondrial volumes (69 and 52%, respectively). These results demonstrate that an HP intake did not prevent soleus muscle atrophy but may sustain protein synthesis and partly preserve fiber type distribution without affecting the ultrastructural composition of fibers. Because the circulating level of free 3,5,3'-triiodothyronine was reduced by 14% with the HP diet, this effect on fiber type distribution, and possibly protein synthesis, may involve thyroid hormones.

scholarly journals Alteration of RhoA Prenylation Ameliorates Cardiac and Vascular Remodeling in Spontaneously Hypertensive Rats

2016 ◽  
Vol 39 (1) ◽  
pp. 229-241 ◽  
Author(s):  
Jian Yang ◽  
Yu-Ning Chen ◽  
Zao-Xian Xu ◽  
Yun Mou ◽  
Liang-Rong Zheng
Keyword(s):  
Cardiac Hypertrophy ◽  
Spontaneously Hypertensive Rats ◽  
Weight Ratio ◽  
Heart Weight ◽  
Farnesyl Pyrophosphate ◽  
Hypertensive Rats ◽  
Cross Sectional ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto ◽  
Aortic Remodeling

Background: In our previous study, farnesyl pyrophosphate synthase (FPPS) was shown to be increased in spontaneously hypertensive rats (SHR) and in mice with angiotensin-II induced cardiac hypertrophy. Overexpression of FPPS induced cardiac hypertrophy and fibrosis in mice, accompanied by an increase in the synthesis of farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). In the present study, we investigated the mechanisms of reversing cardiovascular remodeling in SHR by inhibiting FPPS. Methods and Results: Six-week-old rats were given vehicle or an FPPS inhibitor (alendronate, 100 ug/kg/d) daily for twelve weeks by osmotic mini-pump. The results demonstrated that FPPS inhibition attenuated cardiac hypertrophy and fibrosis in SHR as shown by the heart weight to body weight ratio, echocardiographic parameters, and histological examination. In addition, FPPS inhibition attenuated aortic remodeling as shown by reduced media thickness, media cross-sectional area and collagen of the aorta as well as SBP, DBP, MBP. Furthermore, 12 weeks of alendronate treatment significantly decreased FPP and GGPP levels, RhoA activation and geranylgeranylation in the heart and aorta, all of which were significantly upregulated in SHR compared with normotensive Wistar-Kyoto rats. Conclusion: Taken together, these results indicate that chronic treatment with alendronate decreases the development of cardiac and aortic remodeling, by a pathway which involves inhibition of the geranylgeranylation and activation of RhoA.

scholarly journals Myosin Isoforms and Contractile Properties of Single Fibers of Human Latissimus Dorsi Muscle

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Antonio Paoli ◽  
Quirico F. Pacelli ◽  
Pasqua Cancellara ◽  
Luana Toniolo ◽  
Tatiana Moro ◽  
...  
Keyword(s):  
Latissimus Dorsi ◽  
Fiber Type ◽  
Myosin Heavy Chain Isoforms ◽  
Latissimus Dorsi Muscle ◽  
Myosin Isoforms ◽  
Cross Sectional ◽  
Type Distribution ◽  
Dorsi Muscle ◽  
Fiber Type Distribution

The aim of our study was to investigate fiber type distribution and contractile characteristics of Latissimus Dorsi muscle (LDM). Samples were collected from 18 young healthy subjects (9 males and 9 females) through percutaneous fine needle muscle biopsy. The results showed a predominance of fast myosin heavy chain isoforms (MyHC) with 42% of MyHC 2A and 25% of MyHC 2X, while MyHC 1 represented only 33%. The unbalance toward fast isoforms was even greater in males (71%) than in females (64%). Fiber type distribution partially reflected MyHC isoform distribution with 28% type 1/slow fibers and 5% hybrid 1/2A fibers, while fast fibers were divided into 30% type 2A, 31% type A/X, 4% type X, and 2% type 1/2X. Type 1/slow fibers were not only less abundant but also smaller in cross-sectional area than fast fibers. During maximal isometric contraction, type 1/slow fibers developed force and tension significantly lower than the two major groups of fast fibers. In conclusion, the predominance of fast fibers and their greater size and strength compared to slow fibers reveal that LDM is a muscle specialized mainly in phasic and powerful activity. Importantly, such specialization is more pronounced in males than in females.

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