BACKGROUND: In recent years, researchers discovered that menstrual blood-derived stem cells (MenSCs) have the potential to differentiate into a wide range of tissues including the chondrogenic lineage. In this study, we aimed to investigate the effect of MenSCs encapsulated in fibrin glue (FG) on healing of osteochondral defect in rabbit model. METHODS: We examined the effectiveness of MenSCs encapsulated in FG in comparison with FG alone in the repair of osteochondral defect (OCD) lesions of rabbit knees after 12 and 24 weeks. RESULTS: Macroscopical evaluation revealed that the effectiveness of MenSCs incorporation with FG is much higher than FG alone in repair of OCD defects. Indeed, histopathological evaluation of FG + MenSCs group at 12 weeks post-transplantation demonstrated that defects were filled with hyaline cartilage-like tissue with proper integration, high content of glycosaminoglycan and the existence of collagen fibers especially collagen type II, as well as by passing time (24 weeks post-transplantation), the most regenerated tissue in FG + MenSCs group was similar to hyaline cartilage with relatively good infill and integration. As the same with the result of 12 weeks post-implantation, the total point of microscopical examination in FG + MenSCs group was higher than other experimental groups, however, no significant difference was detected between groups at 24 weeks (p>0.05). CONCLUSION: In summary, MenSCs as unique stem cell population, is suitable for in vivo repair of OCD defects and promising for the future clinical application.
Collagen ; Collagen Type II ; Fibrin Tissue Adhesive ; Fibrin ; Hyalin ; Hyaline Cartilage ; Knee ; Stem Cells

Trichoepitheliomas are benign follicular appendage tumors with differentiation to all three segments of the hair follicle. A 2 years old female domestic short hair cat presented with a mass on the tail. The mass was surgically excised and for histopathologic and immunohistochemical studies, was sent to Department of Pathology. Histologically, the tumor was encapsulated and consisted of many islands of follicular epithelium and also cysts structures which varied in size and shape. The cells of epithelium islands were round to oval and had variable amounts of slightly, eosinophilic cytoplasm and euchromatic nuclei. The cystic structures were lined by a complex layer of squamous epithelium. Often, cells under went an abrupt transition between basal layers and keratinization without the development of a granular cell layer. No tendency of malignancy was seen in this case. According to mentioned characteristics, trichoepithelioma was diagnosed. By immunohistochemical study it was confirmed that this tumor had epithelial origin because squamous tumor cells reacted with the pan-cytokeratin antibody. The expression of β-catenin was predominately cytoplasmic and also together with numerous positive nuclei but membranous expression was inconsistenet. Distribution of neoplastic cells with β-catenin expression was more than 75% and labeling intensity was strong in both cytoplasm and nuclei. According to author’s knowledge, this is the first report of trichoepithelioma in cat in Iran and also investigation of β-catenin expression in feline trichoepithelioma in veterinary literature.