Evaluation of bone repair of critical defects treated with polyamide 6 nanocomposite biomaterials and trimetaphosphate nanoparticles decorated with silver nanoparticles: histomorphometry, microtomographic and immunohistochemical study in rat calvaria

Author(s)

Maria Juliana Sismeiro Dias Morabito

• Document type: Master's Dissertation
• Press: Araçatuba. 2022-05-05.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2021-12-17
• Advisor: Alberto Carlos Botazzo Delbem

Abstract

The aim of this study was to evaluate the influence of nanocomposite materials obtained from the incorporation of sodium trimetaphosphate (TMP) nanoparticles decorated with 2.5% silver nanoparticles (AgNP) in polymeric matrices of polyamide-6 (Pa6), in bone repair of surgically created critical size defects (CDA) in rat calvaria. Thirty male Wistar rats were divided into three groups, according to treatment: Control Group (C) - blood clot; Pa6-AgNP; and Pa6-TMP-AgNP. A 5mm diameter DTC was created on the calvaria of each animal. In Group C, the defect was filled with blood clot only, and in the other groups with scaffolds with Pa6-AgNP and Pa6-TMP-AgNP. The animals were euthanized 30 days after surgery. Microtomographic, histomorphometric and immunohistochemical analyzes were performed. Thus, the area of neoformed bone (AON) was calculated as a percentage of the total area of the original defect, and immunostaining for TGFβ-1, BMP- 2/4 and OCN was determined. From the intergroup analysis, it was observed that the Pa6- TMP-AgNP Group had a larger neoformed bone area, and the Pa6-AgNP Group had higher AON than the control group (P < 0.05). Immunohistochemistry revealed that the Pa6-TMP-AgNP and Pa6-AgNP groups showed high and moderate immunostaining for TGFβ-1 and OCN, respectively. Pa6-TMP-AgNP had a higher number of BMP-2/4 positive cells compared to the other groups (p <0.001). From these results, we can conclude that Pa6-TMP-AgNP provides biological response to bone neoformation, as well as osteoinductive and osteoconductive behavior when used to fill critical defects created in rat calvaria. (AU)

• FAPESP's process: 19/09287-7 - Evaluation of the bone repair of critical defects treated with polyamide 6 nanocomposite biomaterials and trimetaphosphate nanoparticles decorated with silver nanoparticles: histomorphometric study in rats calvaries
• Grantee: Maria Juliana Sismeiro Dias Morábito
• Support Opportunities: Scholarships in Brazil - Master