Avaliação de biocompósitos baseados no hialuronato de sódio e nos nanotubos de carbono em um modelo experimental de osteoporose

Abstract

Sodium hyaluronate (HY) and carbon nanotubes (CNTs) are biomaterials that are able to accelerate the process of bone repair in rats. HY is an extracellular matrix component and it facilitates the cell migration, adhesion, proliferation and differentiation. Additionally, CNTs serve as nucleation sites for deposition of bone matrix and cell proliferation. The aim of this study was to evaluate the effects of HY, multi-walled carbon nanotubes (MWCNTs) and MWCNTs functionalized with HY (MWCNTs-HY) on bone repair of tibiae of rats ovariectomized (OVX) (osteoporotic rats). The animals were divided into five groups: sham, OVX control, OVX 1% HY, OVX MWCNTs (100µg/mL) and OVX MWCNTs-HY (100µg/mL). The bone defect was created by an 1.6 mm diameter drill and after 7, 14 and 21 days of induction of the defects in tibiae, the rats were eutanized and the tibiae were processed for histological analysis, X-ray micro CT (µCT), quantitative PCR and spectroscopy of Raman. OVX control tibiae showed little bone formation with immature trabeculae. On the other hand, tibiae treated with HY, MWCNTs and MWCNT-HY showed an increase in the number of newly formed trabeculae which were more organized and thicker compared to OVX control. µCT analysis demonstrated an increase in the amount of trabecular bone in tibiae treated with HY, MWCNTs and MWCNTs-HY when compared to OVX control. In addition, the expression of BMPs was higher in tibiae treated with MWCNTs and MWCNTs-HY. Raman spectroscopy showed that incorporation of hydroxyapatite and collagen was more pronounced in tibiae treated with HY and MWCNTs-HY. Thus, the results of this study indicate that MWCNTs alone or combined with HY are promising biomaterials for bone tissue engineering