ABSTRACT
Complex wounds in dogs are a recurrent problem in veterinary clinical application and can compromise skin healing; in this sense, tissue bioengineering focused on regenerative medicine can be a great ally. Decellularized and recellularized skin scaffolds are produced to be applied in different and complex canine dermal wounds in the present investigation. Dog skin fragments are immersed in a 0.5% sodium dodecyl sulfate (SDS) solution at room temperature and overnight at 4 °C for 12 days. Decellularized samples are evaluated by histological analysis, scanning electron microscopy (SEM) and gDNA quantification. Some fragments are also recellularized using mesenchymal stem cells (MSCs). Eight adult dogs are divided into three groups for the application of the decellularized (Group I, n = 3) and recellularized scaffolds (Group II, n = 3) on injured areas, and a control group (Group III, n = 2). Wounds are evaluated and measured during healing, and comparisons among the three groups are described. In 30- and 60-day post-grafting, the histopathological analysis of patients from Groups I and II shows similar patterns, tissue architecture preservation, epithelial hyperplasia, hyperkeratosis, edema, and mononuclear inflammatory infiltrate. Perfect integration between scaffolds and wounds, without rejection or contamination, are observed in both treated groups. According to these results, decellularized skin grafts may constitute a potential innovative and functional tool to be adopted as a promising dog cutaneous wound treatment. This is the first study that applies decellularized and recellularized biological skin grafts to improve the healing process in several complex wounds in dogs, demonstrating great potential for regenerative veterinary medicine progress.
ABSTRACT
Racehorses are constantly exposed to stress. Aiming to verify the state of blood components and cortisol alterations during their routine and after races, phagocytosis and oxidative neutrophil burst assays, serum cortisol determination, erythrocytes apoptosis evaluation, lymphoproliferation assays, and blood count tests were performed in thirty Thoroughbred racehorses, which were divided in two groups. The samples were taken right after races (moment 0 d), during rest periods (-11 d, +1 d, +3 d), and after training (-8, +2, +5). In both groups, the phagocytosis showed a decrease in percentage and intensity immediately after the race when comparing samples collected during rest or training periods. In the mean values of oxidative burst on samples collected immediately after the race, group I animals demonstrated a decrease (524.2 ± 248.9) when compared with those samples collected in other moments. No significant differences were found between the results of different moments regarding the apoptotic cells and lymphoproliferation assays. The mean values of serum cortisol levels were increased immediately after racing. There was an increase in the percentage of neutrophils found immediately after the race. It was possible to conclude that, although a transient reduction was found in the number of neutrophils, the horses' adaptive function was not affected.
ABSTRACT
Decellularized extracellular matrix (ECM) has frequently been applied as a biomaterial for tissue engineering purposes. When implanted, their role can be essential for partial trachea replacement in patients that require a viable transplant solution. Acellular canine tracheal scaffolds with preserved ECM structure, flexibility, and proteins were obtained by high pressure vacuum decellularization. Here, we aimed to evaluate the cell adhesion and proliferation of canine tracheal epithelial cells (EpC) and canine yolk sac endothelial progenitor cells (YS) cultivated on canine decellularized tracheal scaffolds and test the in vivo biocompatibility of these recellularized scaffolds implanted in BALB-c nude mice. In order to evaluate the recellularization efficiency, scaffolds were evaluated by scanning electron microscopy (SEM), immunofluorescence, DNA quantification, mycoplasma test, and in vivo biocompatibility. The scaffolds sterility was confirmed, and EpC and YS cells were cultured by 7 and 14 days. We demonstrated by SEM, immunofluorescence, and genomic DNA analyzes cell adhesion to tracheal ECM. Then, recellularized scaffolds were in vivo subcutaneously implanted in mice and after 45 days, the fragments were collected and analyzed by Hematoxylin-Eosin and Gömori Trichrome staining and PCNA, CD4, CD8, and CD68 immunohistochemistry. In vivo results confirmed that the implanted tissue remains preserved and proliferative, and no fibrotic tissue process was observed in animals. Finally, our results showed the recellularization success due the preserved ECM proteins, and that these may be suitable to future preclinical studies applications for partial trachea replacement in tissue engineering.
Subject(s)
Endothelial Progenitor Cells , Trachea , Animals , Dogs , Extracellular Matrix , Humans , Mice , Mice, Nude , Tissue Engineering/methods , Tissue ScaffoldsABSTRACT
BACKGROUND: Cardiovascular diseases are the leading cause of death in many countries. Advances in technology have been promoted in this regard, especially in tissue engineering, to meet the need for tissue or organ grafts. In this way, the porcine model has been used due to its morphophysiological similarity between the human species, mainly regarding the cardiovascular system. Tissue engineering is employed using biological scaffolds that are currently derived from porcine. These scaffolds are produced by decellularization, a process to remove cells aiming to maintain only its three-dimensional structure, formed by extracellular matrix (ECM). Its main objective is to produce organs through recellularized scaffolds that could eventually substitute the ones with impaired functions. AIM: In this way, the present study aimed to establish a new protocol for porcine heart decellularization with potential application on tissue engineering. METHODS: A porcine heart aorta was cannulated with a silicon tube, and the organ was washed in 0.1% phosphate-buffered saline through a peristaltic pump (Harvard Peristaltic Pump - Harvard Apparatus). After that, deionized water was introduced in the same system. The decellularization procedure was carried out using ionic and non-ionic detergents, namely 4% sodium dodecyl sulfate (SDS) and 1% Triton X-100, respectively. SDS was perfused through myocardial circulation at 400 mL/min for 24 h for 6 days. Subsequently, the heart was infused with Triton X-100 and washed by PBS and water for 24 h. The heart volume was measured before and after the recellularization. After macroscopic evaluation, the heart samples were processed and stained by Hematoxylin and Eosin, Masson's Trichrome, Weigert-Van Gieson, Alcian Blue, and Pricrosirius Red techniques for microscopic analysis. To observe the cell adhesion, the recellularization was provided in this scaffold, which was analyzed under immunofluorescence and scanning electronic microscopy. RESULTS: The protocol provided cells remotion, with adequate concentration of remaining DNA. ECM components as collagen type I, elastin, and glycosaminoglycans were successfully maintained. The scaffold showed a high cells adherence and proliferation in the recellularization process. CONCLUSION: According to results, the protocol described in this work preserved the ECM components and the organ architecture, minimizing ECM loss and being possible to state that it is a promising approach to tissue bioengineering. RELEVANCE FOR PATIENTS: This study provides a protocol for whole porcine heart decellularization, which will ultimately contribute to heart bioengineering and may support further studies on biocompatibility relationship of new cells with recellularized scaffolds.
