Tehran University Medical Journal

The cartilage is a connective tissue that, due to the strength of its extracellular matrix, allows the tissue to tolerate mechanical stress without undergoing permanent deformation. It is responsible for the support of soft tissues and due to its smooth surface and elasticity, gives the joints the ability to slip and bend. excessive weight, excessive activity, or trauma can all cause cartilage to injury. The injury can lead to swelling, pain and varying degrees of mobility loss. The process of repairing musculoskeletal (orthopedic) injuries has led to problems in the medical field, which can be attributed to the inherent weakness of adult cartilage tissue. Therefore, this necessitates research focused on the development of a new restructuring strategy by combining chondrocytes or stem cells with scaffolds and growth factors to address these problems. Correspondingly, the recent tissue engineering strategies strongly support the simultaneous use of stem cells, scaffolds and growth factors. It has also been observed that due to the relatively low proliferation of transplanted chondrocytes, new cartilage models construction have examined the use of adipose-derived stem cells. Mature adipose tissue is produced as an important source of multi-functional stem cells that can be easily separated from the stromal vascular fraction (SVF) by adipose liposuction digestion. The adipose-derived stem cells are easily accessible without any serious complications and have the power to differentiate into several cell lines, including chondrocytes as well as, they evidence self-renewal when trapped in gel scaffolds such as collagen. Also, recent studies demonstrate some of the mechanisms involved in the process of making cartilage of adipose-derived stem cells in vitro and their restorative ability in bio-engineered scaffolds in the presence of growth factors. In addition, the important role of non-encoding mRNA molecules (miRNAs) has been identified in the process of chondrogenic differentiation of adipose-derived stem cells. Furthermore, in several studies, the effect of several miRNAs has been confirmed on the regulation of the cartilage differentiation of the adipose-derived stem cells and has also been associated with effective results. In this article, we will present an overview of the advance in adipose-derived stem cells application in cartilage regeneration.

Background: Tissue engineering is a developing multidisciplinary and interdisciplinary field involving the use of bioartificial implants for tissue remodeling with the target for repair and enhancing tissue or organ function. Acellular nerve has been used in experimental models as a peripheral nerve substitute. The purpose of the present study was to evaluate the mechanical and histological characteristics of acellular nerve scaffolds compared to the fresh nerve for application in environmental nerve repair.
Methods: This experimental study was conducted in Ferdowsi University of Mashhad Regeneration Research Laboratory, Mashhad, Iran, from May 2017 to October 2018. In this study for preparing the scaffold. The rats were sacrificed by intraperitoneal anesthesia with 10 % Chloral Hydrate solution. Then sciatic nerve fragments of the rats were removed above the nerve branching site and after cleansing of the tissues were decellularized by Sondell method, briefly nerves were treated with a series of detergent baths consisting of distilled water for 8 h, Triton X-100 for 12 h, and sodium deoxycholate for 24 hours according to the Sondell protocol. All acellularization steps were performed at room temperature. Then decellularized scaffolds were evaluated histologically and mechanically.
Results: The results of tissue evaluations showed that decellularization of scaffolds were done completely, this was demonstrated by hematoxylin and eosin staining and DAPI staining. Also the specialized tissue evaluations by picro-fuchsin staining and evaluation the scaffolds by scanning electron microscopy (SEM) micrographs showed that the collagen and elastin strands are relatively preserved in the extracellular matrix in comparison with control groups. As well as mechanical examination of scaffolds in tensile test showed that extracellular matrix of scaffolds was relatively preserved the main components of tissue compared to control group and scaffolds have good mechanical resistance quality for use in tissue engineering.
Conclusion: The results of the present study showed that decellularized scaffolds that prepared with Sondell decellularization method by preserving the main components of the tissue can be a good platform for investigating cellular behaviors.