Banca de DEFESA: RAFAELA DE MELO BARRETO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RAFAELA DE MELO BARRETO
DATE: 24/02/2022
TIME: 08:30
LOCAL: VÍDEO CONFERÊNCIA
TITLE:

EFFECTS OF THE APPLICATION OF PEPTAN ® HETEROLOGOUS COLLAGEN BIOGEL (PIG AND BOVINE) IN THE REPAIR OF SKIN LESIONS IN MICE

KEY WORDS:

HEALING, INJURY REPAIR, SCAFFOLD, COLLAGEN, BIOMATERIALS.

 

PAGES: 20
BIG AREA: Ciências Biológicas
AREA: Morfologia
SUBÁREA: Histologia
SUMMARY:

The skin is constantly exposed to stimuli from the external environment that can cause some injury and interfere with its barrier function. Therefore, mechanisms guarantee the repair of wounds, but some cases can cause pathological scars that involve, among other factors, impaired function and aesthetics. As a result, numerous therapies are being developed to improve healing. Collagen is a biomaterial with potential to be used because it is abundant, biocompatible, biodegradable and capable of aiding cell migration and proliferation, in addition to improving matrix deposition. Collagen may also be able to influence the immune response through inhibitory receptors and the indirect effects of tolerance that influence the inflammatory phase of skin lesion repair. Therefore, the objective of this work was to produce a heterologous collagen biogel (PEPTAN®) and verify its topical application on the wound on the day the injury was performed and its influence on inflammation and extracellular matrix deposition during the wound closure process. in the skin of Swiss mice. First, the morphological and physicochemical characterization of collagen biogels was performed. Biogels were produced: PEPTAN 1[1], PEPTAN 1[2], PEPTAN 2[1] and PEPTAN 2[2], which differ according to the heterologous source, porcine or bovine, and two different molecular weights. Morphological characterization by SEM showed that porcine collagen granules and gelatins, porcine and bovine, have different shapes, but most have a rounded shape. Bovine collagen granules have a filamentous shape. When comparing the size of the granules, the porcine collagen 5000, porcine 2000 and bovine 5000 presented statistically similar sizes. Bovine collagen 2000 presented smaller granules when compared to porcine collagen 5000, however, it presented granules with a similar size to porcine collagen 2000 and bovine collagen 5000. The size of gelatin granules did not show statistically significant differences. The biogels produced from these biomaterials were structured and porous, with the pores formed from overlapping plates. When comparing the pore size, it was observed that the PEPTAN 1[2] biogel has larger pores when compared to the PEPTAN 2 biogel[2]. The other biogels have pores of similar sizes. XRD analysis showed that collagen peptides and gelatins maintain the helical structure of collagen. These data were confirmed with the analysis of AFM, where it was possible to observe the formation of collagen fibers. Finally, the elemental analysis by EDS showed that in all collagens and gelatines used for the production of biogels, C, O and N were detected, with C being the greatest amount, followed by O and N, typical components of proteins. To evaluate the effects of topical application of PEPTAN® heterologous collagen biogels on skin wound repair, in vivo analyzes were performed. The experimental model consisted of performing two excisional lesions and an incisional lesion on the skin of the back, under anesthesia. Then, the treatment was performed according to the experimental group. The micropore that maintained the topical treatment on the lesions remained for 5 days. The animals were euthanized 7 and 60 days after the injury and the healing was analyzed macro and microscopically after staining with H&E, Toluidine Blue and Gomori Trichrome. In the incisional lesions, macroscopically at 7d, the PEPTAN 1[1] group presented an aesthetically better lesion, reduction of fibroblasts in the PEPTAN 2[1] and PEPTAN 2[2] groups, reduction of mast cells in the PEPTAN 1[2] group when compared with the PEPTAN 2[1] group and At 60d, the incisional lesions of the PEPTAN 1[1] and PEPTAN 1[2] groups present clearer and esthetically better scars when compared to saline. The histomorphometric analysis shows that the PEPTAN 2[2] group showed a higher deposition when compared to the Saline group. In excisional lesions, at 7d, the PEPTAN 1[2] group presented a smaller area, while the PEPTAN 1[1] group presented a larger area. Microscopically, quantitative analysis showed no statistical difference in leukocyte and mast cell counts. It was observed that the PEPTAN 2[1] group had a higher number of fibroblasts when compared to the PEPTAN 1[2] and PEPTAN 2[2] groups. At 60d, the PEPTAN 1[1] and PEPTAN 1[2] groups showed better collagen deposition when compared to the Saline group. The saline group presented a more marked and perceptible transition area between the lesion and the adjacent dermis. While the PEPTAN 1[1] and PEPTAN 1[2] groups showed this smoother transition. We conclude that the application of a dressing containing the PEPTAN® heterologous collagen scaffold improves the healing of skin lesions, with better remodeling of the extracellular matrix. 

BANKING MEMBERS:
Presidente - 2104326 - RAQUEL ALVES COSTA
Interna - 2279745 - ERIKA LORENA FONSECA COSTA DE ALVARENGA
Interna - 2144084 - PRISCILA TOTARELLI MONTEFORTE
Externa à Instituição - TATIANA CARLA TOMIOSSO - UFU
Externo à Instituição - MARCOS AUGUSTO DE SÁ - UFMG
Externo à Instituição - THIAGO CANTARUTI ANSELMO