Certain aspects of mesenchymal stem cells in small ruminants: An overview

In recent years, there has been tremendous progress in the fields of tissue engineering and cellular therapy. Bone tissue engineering is an alternative for regeneration of large bone defects caused by trauma and other bone pathologies. Treatments employed for bone regeneration are based on the use of bioactive molecules, stem cells and scaffold among others. Among these treatments, mesenchymal stem cells (MSCs) have number of advantages: i) available in large quantities from patients (ii) capable of suppressing large immune response and (iii) migrate to sites of injury. A number of farm animal models have been used for tissue-engineered products. Within each animal model, studies were categorised further according to MSC delivery/culture techniques. These techniques included direct application, fibrin glue/gel/clot, intra-articular injection, scaffold, tissue-engineered construct, meniscus tissue, pellets/aggregates and hydrogel. Till date MSCs have been isolated from various sources in small ruminants like bone marrow, adipose tissues, amniotic fluids and characterised by flow cytometry, specific staining methods and immunocytochemistry methods. Moreover, consequent to their isolation and characterization they have differentiated into osteocytes, chondrocytes, adipocytes, neural-like cells, oocyte-like cells etc. This review focuses on the biology of MSCs, including isolation, characterization, purification, in vitro differentiation potential and goat and sheep models that can be used to test tissue-engineered constructs.