Prevention of myonecrosis in mdx mice: Effect of immobilization by the local tetanus method

1992 ◽  
Vol 14 (5) ◽  
pp. 319-322 ◽  
Author(s):  
Yoshihiko Mizuno
Keyword(s):  
Mdx Mice ◽  
Author(s):  
H.D. Geissinger ◽  
C.K. McDonald-Taylor

A new strain of mice, which had arisen by mutation from a dystrophic mouse colony was designated ‘mdx’, because the genetic defect, which manifests itself in brief periods of muscle destruction followed by episodes of muscle regeneration appears to be X-linked. Further studies of histopathological changes in muscle from ‘mdx’ mice at the light microscopic or electron microscopic levels have been published, but only one preliminary study has been on the tibialis anterior (TA) of ‘mdx’ mice less than four weeks old. Lesions in the ‘mdx’ mice vary between different muscles, and centronucleation of fibers in all muscles studied so far appears to be especially prominent in older mice. Lesions in young ‘mdx’ mice have not been studied extensively, and the results appear to be at variance with one another. The degenerative and regenerative aspects of the lesions in the TA of 23 to 26-day-old ‘mdx’ mice appear to vary quantitatively.


Author(s):  
H. D. Geissinge ◽  
L.D. Rhodes

A recently discovered mouse model (‘mdx’) for muscular dystrophy in man may be of considerable interest, since the disease in ‘mdx’ mice is inherited by the same mode of inheritance (X-linked) as the human Duchenne (DMD) muscular dystrophy. Unlike DMD, which results in a situation in which the continual muscle destruction cannot keep up with abortive regenerative attempts of the musculature, and the sufferers of the disease die early, the disease in ‘mdx’ mice appears to be transient, and the mice do not die as a result of it. In fact, it has been reported that the severely damaged Tibialis anterior (TA) muscles of ‘mdx’ mice seem to display exceptionally good regenerative powers at 4-6 weeks, so much so, that these muscles are able to regenerate spontaneously up to their previous levels of physiological activity.


Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 481
Author(s):  
Paulina Podkalicka ◽  
Olga Mucha ◽  
Katarzyna Kaziród ◽  
Iwona Bronisz-Budzyńska ◽  
Sophie Ostrowska-Paton ◽  
...  

Duchenne muscular dystrophy (DMD), caused by a lack of functional dystrophin, is characterized by progressive muscle degeneration. Interestingly, dystrophin is also expressed in endothelial cells (ECs), and insufficient angiogenesis has already been hypothesized to contribute to DMD pathology, however, its status in mdx mice, a model of DMD, is still not fully clear. Our study aimed to reveal angiogenesis-related alterations in skeletal muscles of mdx mice compared to wild-type (WT) counterparts. By investigating 6- and 12-week-old mice, we sought to verify if those changes are age-dependent. We utilized a broad spectrum of methods ranging from gene expression analysis, flow cytometry, and immunofluorescence imaging to determine the level of angiogenic markers and to assess muscle blood vessel abundance. Finally, we implemented the hindlimb ischemia (HLI) model, more biologically relevant in the context of functional studies evaluating angiogenesis/arteriogenesis processes. We demonstrated that both 6- and 12-week-old dystrophic mice exhibited dysregulation of several angiogenic factors, including decreased vascular endothelial growth factor A (VEGF) in different muscle types. Nonetheless, in younger, 6-week-old mdx animals, neither the abundance of CD31+α-SMA+ double-positive blood vessels nor basal blood flow and its restoration after HLI was affected. In 12-week-old mdx mice, although a higher number of CD31+α-SMA+ double-positive blood vessels and an increased percentage of skeletal muscle ECs were found, the abundance of pericytes was diminished, and blood flow was reduced. Moreover, impeded perfusion recovery after HLI associated with a blunted inflammatory and regenerative response was evident in 12-week-old dystrophic mice. Hence, our results reinforce the hypothesis of age-dependent angiogenic dysfunction in dystrophic mice. In conclusion, we suggest that older mdx mice constitute an appropriate model for preclinical studies evaluating the effectiveness of vascular-based therapies aimed at the restoration of functional angiogenesis to mitigate DMD severity.


2021 ◽  
Author(s):  
Sarbesh R. Pandeya ◽  
Janice A. Nagy ◽  
Daniela Riveros ◽  
Carson Semple ◽  
Rebecca S. Taylor ◽  
...  

2021 ◽  
pp. 1-5
Author(s):  
Gian Luca Vita ◽  
Luisa Politano ◽  
Angela Berardinelli ◽  
Giuseppe Vita

Background: Increasing evidence suggests that Duchenne muscular dystrophy (DMD) gene is involved in the occurrence of different types of cancer. Moreover, development of sarcomas was reported in mdx mice, the murine model of DMD, in older age. So far, nine isolated DMD patients were reported with concomitant cancer, four of whom with rhabdomyosarcoma (RMS), but no systematic investigation was performed about the true incidence of cancer in DMD. Methods: All members of the Italian Association of Myology were asked about the occurrence of cancer in their DMD patients in the last 30 years. Results: Four DMD patients with cancer were reported after checking 2455 medical records. One developed brain tumour at the age of 35 years. Two patients had alveolar RMS at 14 and 17 years of age. The fourth patient had a benign enchondroma when 11-year-old. Conclusion: Prevalence of cancer in general in the Italian DMD patients does not seem to be different from that in the general population with the same age range. Although the small numbers herein presented do not allow definitive conclusion, the frequent occurrence of RMS in DMD patients raises an alert for basic researchers and clinicians. The role of DMD gene in cancer merits further investigations.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Mongillo ◽  
M Franzoso ◽  
V Prando ◽  
L Dokshokova ◽  
A Di Bona ◽  
...  

Abstract Background Sympathetic neurons (SNs) innervate the myocardium with a defined topology that allows physiological modulation of cardiac activity. Neurotrophins released by cardiac cells control SN viability and myocardial distribution, which are impaired in heart diseases with reduced (e.g. heart failure) or heterogenous sympathetic stimulation (e.g. arrhythmias). We previously demonstrated that SNs interact directly with cardiomyocytes (CMs) at neuro-cardiac junctions (NCJ), and such structured contact sites allow neurons to efficiently activate β-adrenoceptors on the myocyte membrane. Aims We here asked whether NCJs are functional for retrograde (myocyte to neuron) neurotrophic signaling. Methods and results Electron microscopy and immunofluorescence on mouse heart slices and SN/CM co-cultures showed that the NGF receptor, TrkA, is preferentially found in correspondence of the NCJ. Consistently, neurons taking structured contact with CMs showed fast TrkA activation and its retrograde transport to the soma, which was monitored using live confocal imaging in cells expressing TrkA-RFP. In accord with NGF dependent effects, CM-contacted SN showed larger synaptic varicosities and did not require NGF supplementation in the culture medium. In support that NGF locally released at NCJs sustains SN viability, the neurotrophin concentration in the culture medium was 1.61 pg/mL, and did not suffice to maintain neuronal viability, which was also perturbed (66% decrease of neuronal density) by silencing NGF expression in CMs. These results support that the NCJ is essential for intercellular neurotrophin signaling. Consistently, by applying competitive inhibition of TrkA with increasing doses of K252a, we estimated NGF concentration at the contact site to be about 1000-fold higher than that released by CM in the culture medium. To seek for the structural determinants of the NCJ, we focused on dystrophin, based on the finding that the protein accumulates on the CM membrane portion contacted by SNs, as observed in mouse heart slices, and co-cultured CMs. In support of a role of CM-expressed dystrophin in neurotrophic signaling, hearts from dystrophin-KO (mdx) mice showed 74.36% decrease of innervation, with no significant changes of NGF expression. In line with the purported role of NCJs, in co-cultures between wild type SNs and mdx CMs, TrkA activation (TrkA movements toward SN soma (%): WTCM-WTSN=18±4; MDXCM-WTSN= 12±3; p<0,05) and neuronal survival were reduced. Conclusions Taken together, our results suggest that NGF-dependent signaling to SNs requires a direct and specialized interaction with myocytes, and that loss of dystrophin at the CM membrane impairs retrograde signaling to the neurons leading to cardiac sympathetic dys-innervation. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): University of Padova


2002 ◽  
Vol 283 (3) ◽  
pp. C773-C784 ◽  
Author(s):  
Karl Rouger ◽  
Martine Le Cunff ◽  
Marja Steenman ◽  
Marie-Claude Potier ◽  
Nathalie Gibelin ◽  
...  

The mdx mouse is a model for human Duchenne muscular dystrophy (DMD), an X-linked degenerative disease of skeletal muscle tissue characterized by the absence of the dystrophin protein. The mdx mice display a much milder phenotype than DMD patients. After the first week of life when all mdx muscles evolve like muscles of young DMD patients, mdx hindlimb muscles substantially compensate for the lack of dystrophin, whereas mdx diaphragm muscle becomes progressively affected by the disease. We used cDNA microarrays to compare the expression profile of 1,082 genes, previously selected by a subtractive method, in control and mdx hindlimb and diaphragm muscles at 12 time points over the first year of the mouse life. We determined that 1) the dystrophin gene defect induced marked expression remodeling of 112 genes encoding proteins implicated in diverse muscle cell functions and 2) two-thirds of the observed transcriptomal anomalies differed between adult mdx hindlimb and diaphragm muscles. Our results showed that neither mdx diaphram muscle nor mdx hindlimb muscles evolve entirely like the human DMD muscles. This finding should be taken under consideration for the interpretation of future experiments using mdx mice as a model for therapeutic assays.


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