Plasma-Activated Polydimethylsiloxane Microstructured Pattern with Collagen for Improved Myoblast Cell Guidance

We focused on polydimethylsiloxane (PDMS) as a substrate for replication, micropatterning, and construction of biologically active surfaces. The novelty of this study is based on the combination of the argon plasma exposure of a micropatterned PDMS scaffold, where the plasma served as a strong tool for subsequent grafting of collagen coatings and their application as cell growth scaffolds, where the standard was significantly exceeded. As part of the scaffold design, templates with a patterned microstructure of different dimensions (50 × 50, 50 × 20, and 30 × 30 μm2) were created by photolithography followed by pattern replication on a PDMS polymer substrate. Subsequently, the prepared microstructured PDMS replicas were coated with a type I collagen layer. The sample preparation was followed by the characterization of material surface properties using various analytical techniques, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). To evaluate the biocompatibility of the produced samples, we conducted studies on the interactions between selected polymer replicas and micro- and nanostructures and mammalian cells. Specifically, we utilized mouse myoblasts (C2C12), and our results demonstrate that we achieved excellent cell alignment in conjunction with the development of a cytocompatible surface. Consequently, the outcomes of this research contribute to an enhanced comprehension of surface properties and interactions between structured polymers and mammalian cells. The use of periodic microstructures has the potential to advance the creation of novel materials and scaffolds in tissue engineering. These materials exhibit exceptional biocompatibility and possess the capacity to promote cell adhesion and growth.

Effect of Boron-Doped Mesoporous Bioactive Glass Nanoparticles on C2C12 Cell Viability and Differentiation: Potential for Muscle Tissue Application

Mesoporous bioactive glasses (MBGs) exhibit a high surface area and a highly ordered mesoporous structure. MBGs have potential for both hard and soft tissue engineering applications. MBGs may be doped with biologically active ions to tailor their biological activity. Boron is being widely studied as a dopant of bioactive glasses. Recently, research has demonstrated the potential of boron-containing bioactive glasses for muscle regeneration. In this study, boron-containing MBGs, 10B-MBG and 18B-MBG nanoparticles, were produced by a microemulsion-assisted sol-gel approach for potential muscle regeneration applications. First, X-ray diffraction (XRD), Fourier transform infrared (FTIR), and energy-dispersive X-ray spectroscopy (EDX) analyses were conducted to study the chemical structure and composition of the nanoparticles. To examine the nanoparticle morphology, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images were analyzed. Both SEM images and particle size distribution determined by dynamic light scattering (DLS) indicated a decrease of the average particle size after boron doping. TEM images indicated a slit-shaped mesoporous structure of nanoparticles for all compositions. The ζ potential was measured, and a negative surface charge was found for all study groups due to the presence of silanol groups. Cytocompatibility and fluorescence microscopy studies were also carried out. The results indicated that low concentrations (0.1 and 1 mg mL^-1) of all MBG nanoparticles led to high viability of C2C12 cells. Fluorescence microscopy images indicated that at lower nanoparticle concentrations (0.1 and 1 mg mL^-1), C2C12 cells appeared to differentiate into myotubes, which was indicated by a spindle-shaped morphology. For 10 mg mL^-1 concentration of nanoparticles, C2C12 cells had a lower aspect ratio (estimated qualitatively by inspection of the images), which implied a lower degree of differentiation. Boron-doped MBG nanoparticles in reduced concentrations are suitable to induce differentiation of C2C12 cells into myotubes, indicating their potential for applications in muscle tissue repair.

Diospyros kaki extract protects myoblasts from oxidative stress-induced cytotoxicity via secretions derived from intestinal epithelium

Under oxidative stress, reactive oxygen species (ROS) alter signal transduction and induce macromolecular damage in cells. Such oxidative damage can lead to sarcopenia, an age-related syndrome characterized by a progressive loss of mass and strength of skeletal muscles. Because food components do not directly come in contact with muscle cells, we focused on the effects of secretions produced by stimulated intestinal epithelial cells on oxidative stress in myoblast cells. An extract of Diospyros kaki was fractionated using different concentrations of ethanol. Each fraction showed different levels of antioxidant and phenolic compounds. The biological activity was evaluated using a Caco-2 cell coculture system. Secretions from Caco-2 cells exposed to 0.5 mg/mL D. kaki extract attenuated the oxidative stress-induced reduction of C2C12 cell viability, suggesting that the D. kaki extract could stimulate intestinal epithelial cells to produce secretions that reduce oxidative stress in myoblasts in vitro.

Daidzein stimulates fatty acid-induced fat deposition in C2C12 myoblast cells via the G protein-coupled receptor 30 pathway

Fat deposition in skeletal muscle is an important aspect of improving meat quality. Isoflavones can promote animal anabolism, but whether and how they regulate muscle fat deposition remain largely unclear. In this study, we explored the role and corresponding molecular mechanism of one of the major isoflavones, daidzein, in fat deposition in C2C12 myoblast cells. In the absence of fatty acids (FAs), daidzein did not promote triglyceride synthesis and lipid droplet formation in cells but increased sterol regulatory element-binding protein 1c (SREBP-1c) expression and maturation. In the presence of FAs, daidzein enhanced FAs-induced fat deposition and the SREBP-1c signaling. Daidzein promoted FAs-induced nuclear factor κB1 (NFκB1) phosphorylation and activated the SREBP-1c signaling in a PI3K-dependent manner. G protein-coupled receptor 30 (GPR30) knockdown but not estrogen receptor α (ERα) knockdown blocked the stimulation of daidzein on the PI3K-NFκB1-SREBP-1c signaling pathway, while both knockdown did not affect the stimulation of FAs on this signaling. qRT-PCR and ChIP-qPCR further detected that daidzein stimulated NFκB1-targeted SREBP-1c transcription. Daidzein did not affect ERα expression in cells, but it stimulated GPR30 expression and cytoplasmic localization. These results reveal that daidzein promotes FAs-induced fat deposition through the GPR30 signaling in C2C12 myoblast cells.