Drug delivery sistem in injetable and 3D impress hidrogel to bone repair in ovariectomized rats

Abstract

The objective of this project will be investigated the influence of local drug delivery systems using hydrogels embedded with drug combined with bioglass on in vitro osteogenesis, as well as on the regeneration of critical bone defects in femurs of ovariectomized rats. The drugs that will be combined with bioglass particles will be raloxifene and strontium ranelate, which will have a local action. This project will be executed in 3 stages. In the first, the synthesis and characterization of the bioglass will be performed, following by its association with the drugs, through the sonochemical method. Sequentially the characterization of the drug combined with bioglass hydrogels will be performed, both hydrogels, injectable and 3D printing, with a cylindrical shape of 4x4mm. In the second stage, the cell culture tests will be performed using mesenchymal cells differentiated into osteoblasts, isolated from femurs of ovariectomized rats and submitted to radiotherapy. Cell activity and differentiation will be evaluated, as well as the expression of genes for osteogenesis. After the validation by physicochemical tests and biological tests in cell cultures, the third step, the in vivo experiment, will be performed. For this, young adult female Wistar rats (n=8 for each group and subgroup) will be divided into 3 groups: S- submitted to sham surgery of bilateral ovariectomy; O- submitted to bilateral ovariectomy surgery. After 8 weeks of surgeries, all animals will be submitted to a critical bone defect in the distal epiphysis of the femurs bilaterally, which will be filled with clot, hydrogel incorporated with raloxifene combined with bioglass or hydrogel incorporated with strontium ranelate combined with bioglass. All animals will receive the same medicament in the drug delivery system, but in the right femurs the hydrogel will be injectable, while in the left femurs the hydrogel will be printed in a 4x4 mm cylinder design to fill the defect. The animals will be euthanized 2 and 8 weeks after the surgical procedure, and 10 ml of blood will be taken from each animal for cytokine analysis. After euthanasia, the femurs will be submitted to computerized microtomography analysis for the morphometric evaluation of the bone formed in the critical defect area. Subsequently, these same specimens will be submitted to laboratory processing for histological, histomorphometric and immunohistochemical analysis. Quantitative data will be submitted to the test for normality test to select the appropriate statistical test (parametric or non-parametric), with a significance level of 5%. (AU)