Titanium dioxide doped phosphate glasses modulating pro-inflammatory macrophages reponses for tissue regeneration application

Abstract

ObjectivesThere is an urgent need to understand how novel biomaterials interact with the immune system to improve patients’ safety. This study aimed to explore the immune-inflammatory responses of titanium dioxide doped phosphate glass (TDPG) using RAW 264.7 macrophage cells. MethodsThe ion release was investigated using Inductively Coupled Plasma Optical Emission Spectroscopy and Ion Chromatography. Cell attachment, viability, percentage apoptosis, cell cycle stages, release of reactive oxygen species (ROS) and pro-inflammatory (IL-6, IL-β & TNF-α) and anti-inflammatory (IL-10) cytokines expression were explored for cells grown directly or indirectly in presence of TDPG using different microscopy techniques, XTT assay, flow cytometry, ROS Assay and RT-PCR respectively. The commercially available ProRoot® MTA was used as a control material and cells grown in the normal tissue culture medium was used as control cells. ResultsTDPG released less calcium but more phosphorus than ProRoot® MTA. Aluminum release was only seen with ProRoot® MTA, but sodium, and titanium were detected with TDPG. Macrophages grown in presence of TDPG or its extract showed rounded morphology with expression of F4/80 surface marker, comparable viability and percentage apoptosis to control cells while with ProRoot® MTA, cells showed an enlarged morphology, lower viability, higher percentage apoptosis than control cells. TDPG even at twice dose as ProRoot® MTA did not affect the cell cycle stages as control cells while ProRoot® MTA induced significant changes in the G1, S, G2/M phases and increased cell granularity. ROS level significantly increased in presence of ProRoot® MTA when compared with TDPG and control cells. A transient induction of pro-inflammatory cytokines (IL-6, IL1β, TNF-α) was observed with TDPG treatments whereas their levels sustained for longer time periods with ProRoot® MTA. ConclusionsTDPG showed better immune response than ProRoot® MTA and can modulate tissue regeneration.