Decellularized peripheral nerve grafts by a modified protocol for repair of rat sciatic nerve injury

Studies have shown that acellular nerve xenografts do not require immunosuppression and use of acellular nerve xenografts for repair of peripheral nerve injury is safe and effective.However,there is currently no widely accepted standard chemical decellularization method.The purpose of this study is to investigate the efficiency of bovine-derived nerves decellularized by the modified Hudson’s protocol in the repair of rat sciatic nerve injury.In the modified Hudson’s protocol,Triton X-200 was replaced by Triton X-100,and DNase and RNase were used to prepare accelular nerve xenografts.The efficiency of bovine-derived nerves decellularized by the modified Hudson’s protocol was tested in vitro by hematoxylin&eosin,Alcian blue,Masson’s trichrome,and Luxol fast blue staining,immunohistochemistry,and biochemical assays.The decellularization approach excluded cells,myelin,and axons of nerve xenografts,without affecting the organization of nerve xenografts.The decellularized nerve xenograft was used to bridge a 7 mm-long sciatic nerve defect to evaluate its efficiency in the repair of peripheral nerve injury.At 8 weeks after transplantation,sciatic function index in rats subjected to transplantation of acellular nerve xenograft was similar to that in rats undergoing transplantation of nerve allograft.Morphological analysis revealed that there were a large amount of regenerated myelinated axons in acellular nerve xenograft;the number of Schwann cells in the acellular nerve xenograft was similar to that in the nerve allograft.These findings suggest that acellular nerve xenografts prepared by the modified Hudson’s protocol can be used for repair of peripheral nerve injury.This study was approved by the Research Ethics Committee,Research and Technology Chancellor of Guilan University of Medical Sciences,Iran(approval No.IR.GUMS.REC.1395.332)on February 11,2017.

In Vivo Confocal Microscopic Observation of Lamellar Corneal Transplantation in the Rabbit Using Xenogenic Acellular Corneal Scaffolds as a Substitute

Background： The limiting factor to corneal transplantation is the availability of donors. Research has suggested that xenogenic acellular corneal scaffolds （XACS） may be a possible alternative to transplantation. This study aimed to investigate the viability of performing lamellar corneal transplantation （LCT） in rabbits using canine XACS. Methods： Fresh dog corneas were decellularized by serial digestion, and LCT was performed on rabbit eyes using xenogeneic decellularized corneal matrix. Cellular and morphological changes were observed by slit-lamp, light, and scanning electron microscopy at 7, 30 and 90 days postoperatively, lmmunocytochemical staining for specific markers such as keratin 3, vimentin and MUC5AC, was used to identify cells in the graft. Results： Decellularized xenogenic corneal matrix remained transparent for about l-month after LCT. The recipient cells were able to survive and proliferate into the grafts. Three months after transplantation, grafts had merged with host tissue, and graft epithelialization and vascularization had occurred. Corneal nerve fibers were able to grow into the graft in rabbits transplanted with XACS. Conclusions： Xenogenic acellular corneal scaffolds can maintain the transparency of corneal grafts about 1-month and permit growth of cells and nerve fibers, and is, therefore, a potential substitute or carrier for a replacement cornea.

3D porous acellular cartilage matrix scaffold with surface mediated sustainable release of TGF-β3 for cartilage engineering

Acellular tissue matrix scaffolds are much closer to tissue’s complex natural structure and biological characteristics,thus assess great advantages in cartilage engineering.We used rabbit costal cartilage to prepare acellular microfilaments and further 3D porous acellular cartilage scaffold via crosslinking.Poly(_L-lysine)/hyaluronic acid(PLL/HA)multilayer film was then built up onto the surface of the resulting porous scaffold.Furthermore,TGF-β3 was loaded into the PLL/HA multilayer film coated scaffold to obtain a 3D porous acellular cartilage scaffold with sustained releasing of TGF-β3 up to 60 days.The success of this project will provide a new way for the treatment of articular cartilage defects.Meanwhile,the anchoring and on-site sustained releasing of growth factors mediated by polyelectrolyte multilayered film can also provide a new method for improving the biocompatibility and the biofunctionality for other implanted biomaterials.

O-alg-THAM/gel hydrogels functionalized with engineered microspheres based on mesenchymal stem cell secretion recruit endogenous stem cells for cartilage repair

Lacking self-repair abilities,injuries to articular cartilage can lead to cartilage degeneration and ultimately result in osteoarthritis.Tissue engineering based on functional bioactive scaffolds are emerging as promising approaches for articular cartilage regeneration and repair.Although the use of cell-laden scaffolds prior to implantation can regenerate and repair cartilage lesions to some extent,these approaches are still restricted by limited cell sources,excessive costs,risks of disease transmission and complex manufacturing practices.Acellular approaches through the recruitment of endogenous cells offer great promise for in situ articular cartilage regeneration.In this study,we propose an endogenous stem cell recruitment strategy for cartilage repair.Based on an injectable,adhesive and self-healable o-alg-THAM/gel hydrogel system as scaffolds and a biophysio-enhanced bioactive microspheres engineered based on hBMSCs secretion during chondrogenic differentiation as bioactive supplement,the as proposed functional material effectively and specifically recruit endogenous stem cells for cartilage repair,providing new insights into in situ articular cartilage regeneration.