Veterinary Research Forum

Abstract Bone tissue engineering offers a potential alternative to conventional grafting by combining biocompatible scaffolds with biological stimulants. Polycaprolactone (PCL) is a biodegradable polyester with good mechanical strength and biocompatibility. Hydroxyapatite (HA) is a calcium phosphate mineral that is a major component of bone and has excellent bioactivity and biocompatibility. This research investigated the histopathological effects of PCL-HA nanocomposite scaffolds along with their combination with platelet-rich fibrin (PRF), on the regeneration of bone in rabbit calvarial bone defects. Four circular full-thickness bone defects of 5.00 mm in diameter were created on the calvarial bone of 15 male New Zealand white rabbits. Three defects were filled with PRF, PCL-HA, and PCL-HA/PRF, and one defect was served as a control with no filler. Histopathological evaluations were conducted at 4-, 8-, and 12-weeks post-implantation. Data were evaluated using the Kruskal-Wallis and Mann-Whitney U tests. Significant differences were observed between the treatment and control groups regarding bone regeneration throughout all 12^th weeks studied. In the 4^th weeks, no significant differences in bone regeneration were noted among the treatment groups. In the 8^th weeks, most new bone formation was observed in the PCL-HA/PRF group. Both the PCL-HA and PCL-HA/PRF groups significantly improved bone regeneration compared to the control and PRF groups, with the PCL-HA/PRF group demonstrating the greatest bone formation, and vascularization and the lowest inflammation by the 12^th week. Thus, PCL-HA/PRF could be considered as a suitable alternative to bone grafts and could be increasingly utilized in orthopedic surgery and bone tissue engineering.

Abstract Scaffolds play a crucial role in tendon healing by providing structural support, promoting cell infiltration, and guiding tissue regeneration. Polycaprolactone (PCL) has been used as a polymer in biological scaffolds for several tissue engineering studies. This study aimed to investigate the effects of curcumin-loaded PCL scaffold on Achilles tendon using a tenotomy model in rats. Twenty adult male Wistar rats were randomized into two groups. In control group, tenotomy and suture placement were performed. The identical intervention followed by the implantation of curcumin-loaded PCL scaffold around the tendon stumps was performed in the treatment group. The nanofibrous PCL scaffold containing 5.00% curcumin was fabricated by electrospinning. Walking track analysis was performed weekly. Then, after 6 weeks, histopathological examination and tendon mechanical tests were performed. The weekly walking track analysis revealed a significant improvement in Achilles functional index in scaffold-treated rats from week three to six. The rate of functional improvement was remarkably slower in the control group. Histopathological examination revealed aseptic inflammation and enhanced neovascularization in the treatment group. Also, collagen arrangement and density were significantly improved in this group compared to the control samples including less regular orientation and loose organization of collagen fibers. Significant increase in mechanical properties, except for strain, was observed in the treatment group. The present study demonstrated that implantation of curcumin-loaded PCL scaffold resulted in increased fibrillar architecture, as well as improved mechanical properties and Achilles functional index in rats. To reduce the biodegradation-induced inflammation, an anti-inflammatory treatment is recommended.

Abstract The aim of this study was to investigate the interactions between rat intestine decellularized scaffold and human adipose derived mesenchymal stem cells. Rat large intestine was dissected in fragments and decellularized by physicochemical methods. The scaffolds were loaded by human adipose derived mesenchymal stem cells expressing green fluorescent protein. Microscopic sections were prepared from the scaffolds after two weeks of culture with stem cells and studied by histological methods. The interactions of scaffolds with MSCs were also studied by electron microscopy. Histological and electron microscopy studies revealed human mesenchymal stem cell adhesion, migration, division and maintenance during the 14 days of culture in vitro. According to the results, scaffolds prepared from rat intestine matrix could be a suitable scaffold for studying in vitro cell behaviors such as division, migration and attachment. These various behaviors of cultured cells might be due to inductive effects of the extracellular matrix derived scaffold. However, more investigations are required to discover the exact effects of this scaffold and its interactions with mesenchymal stem cells.