Fractal dimension analysis reveals skeletal muscle disorganization in mdx mice

Abstract

Duchenne Muscular Dystrophy (DMD) is characterized by muscle extracellular matrix disorganization due to the increased collagen deposition leading to fibrosis that significantly exacerbates disease progression. Fractal dimension analysis is a method that quantifies tissue/cellular disorganization and characterizes complex structures. The first objective of the present study was use fractal analysis to evaluate extracellular matrix disorganization in mdx mice soleus muscle. Next, we mimic a hyper-proliferation of fibrogenic cells by co-culturing NIH3T3 fibroblasts and C2C12 myoblasts to test whether fibroblasts induce disorganization in myoblast arrangement. Here, we show mdx presented high skeletal muscle disorganization as revealed by fractal analysis. Similarly, this method revealed that myoblasts co-cultured with fibroblast also presented cellular arrangement disorganization. We also reanalyzed skeletal muscle microarrays transcriptomic data from mdx and DMD patients that revealed transcripts related to extracellular matrix organization. This analysis also identified Osteoglycin, which was validated as a potential regulator of ECM organization in mdx dystrophic muscles. Our results demonstrate that fractal dimension is useful tool for the analysis of skeletal muscle disorganization in DMD and also reveal a fibroblast-myoblast cross-talk that contributes to "in vitro" myoblast disarrangement.

Dexamethasone and Training-Induced Cardiac Remodeling Improve Cardiac Function and Arterial Pressure in Spontaneously Hypertensive Rats

“…Sections of 5 mm thickness (hematoxylin-eosin staining, Easy Path, SP) were used for capillary density and myocyte diameter, 7 while 7 mm thickness (Picrosirius Red staining, Merck-Millipore, USA) were used for collagen deposition area analyses. 24 All images were captured using Leica MC170 HD camera, coupled to the Leica DM4 B microscope (20 or 40x magnification). Analyses (off-line) were performed using Ima-geJ software, on blinded slides.…”

Fractal dimension in the evaluation of different treatments of muscular injury in rats

“…In a study by Cury et al (2018) using the box counting method, the muscle disorganization of elderly rats with muscular dystrophy (mdx) and healthy animals was differentiated. The aspect of the dystrophic muscle resembles the injured muscle, showing affinity of the DF to differentiate between injured and healthy muscles.…”

“…In this way FD has been successfully used to identify cancer cells, discriminate the architecture of muscles with dystrophy as well as differentiate brain cells (Lee et al, 2014;Pantic et al, 2015Pantic et al, , 2014Cury et al, 2018), and these processes are linked to the number of nuclei in the analyzed site. In another study from our group (Ozaki et al, 2015), FD proved to be effective in differentiating injured muscle from healthy muscle, a fact that was again observed in the present study.…”

Preventive training interferes with mRNA-encoding myosin 7 and collagen I expression during pulmonary arterial hypertension

“…The result was quantitatively expressed as the FD of the object with DF ¼ (Log Nr/Log r_1; Nr as the quantity of equal elements needed to fill the original object with scale applied to the object). FD was calculated using the ImageJ software set between 0 and 2, without distinguishing different textures [23,24,25].…”