Evaluation of Collection and Distribution of Samples for Histological,Stereological Analysis and Cell Culture of Canine Mast Cell Tumors

Objective: To collect high quality, representative tissue material from tumors and manage its distribution to different laboratories. Design: Prospective controlled study. Animals: Thirty-six dogs with mast cell tumors. Procedures: The samples were submitted for the following analyses: stereology;histopathology;cell culture;breakdown for cytogenetic analysis of chromosomes (based on the Boxer breed published genome);Cell lysis for Real Time PCR and quantification of gene expression of CX 43, 32 and E-cadherin in canine mast cells. Results: Cytogenetic chromosome analysis, 90.9% of the samples were considered to be of good quality. For gene expression quantification of CX 43, 32 and E-cadherin in canine mast cell tumors (MCT), 95.5% of samples were considered to be of good quality. Conclusions and Clinical Relevance: We seek to assess the importance of surgical collection and post-surgical tissue preparation on laboratory testing by collecting surgical material appropriately to allow accurate diagnosis and reliable clinical prognosis and minimize errors caused by inadequate preparation of samples.

Use of hybrid chitosan membranes and human mesenchymal stem cells from the Wharton jelly of umbilical cord for promoting nerve regeneration in an axonotmesis rat model

Many studies have been dedicated to the development of scaffolds for improving post-traumatic nerve regeneration. The goal of this study was to assess the effect on nerve regeneration, associating a hybrid chitosan membrane with non-differentiated human mesenchymal stem cells isolated from Wharton＇s jelly of umbilical cord, in peripheral nerve reconstruction after crush injury. Chromosome analysis on human mesenchymal stem cell line from Wharton＇s jelly was carried out and no structural alterations were found in metaphase. Chitosan membranes were previously tested in vitro, to assess their ability in supporting human mesenchymal stem cell survival, expansion, and differentiation. For the in vivo testing, Sasco Sprague adult rats were divided in 4 groups of 6 or 7 animals each： Group 1, sciatic axonotmesis injury without any other intervention （Group 1-Crush）; Group 2, the axonotmesis lesion of 3 mm was infiltrated with a suspension of 1 250 -1 500 human mesenchymal stem cells （total volume of 50 pL） （Group 2-CrushCell）; Group 3, axonotmesis lesion of 3 mm was enwrapped with a chitosan type Ill membrane covered with a monolayer of non-differentiated human mesenchymal stem cells （Group 3-CrushChitlllCell） and Group 4, axonotmesis lesion of 3 mm was enwrapped with a chitosan type III membrane （Group 4-CrushChiUll）. Motor and sensory functional recovery was evaluated throughout a healing period of 12 weeks using sciatic functional index, static sciatic index, extensor postural thrust, and withdrawal reflex latency. Stereological analysis was carded out on regenerated nerve fibers. Results showed that infiltration of human mesenchymal stem cells, or the combination of chitosan membrane enwrapment and human mesenchymal stem cell enrichment after nerve crush injury provide a slight advantage to post-traumatic nerve regeneration. Results obtained with chitosan type III membrane alone confirmed that they significantly improve post-traumatic axonal regrowth and may represent a very promising clinical tool in peripheral nerve reconstructive surgery. Yet, umbilical cord human mesenchymal stem cells, that can be expanded in culture and induced to form several different types of cells, may prove, in future experiments, to be a new source of cells for cell therapy, including targets such as peripheral nerve and muscle.