  Mesoporous bioactive glasses (MBGs) are bioceramics designed to induce bone
tissue regeneration and very useful materials with the ability to act as drug
delivery systems. MBGs can be implanted in contact with bone tissue in
different ways, as particulate material, in 3D scaffolds or as nanospheres. In
this work, we assessed the effects of particles of mesoporous bioactive glass
MBG-75S and mesoporous nanospheres NanoMBG-75S on RAW 264.7 and J774A.1
macrophages, which present different sensitivity and are considered as ideal
models for the study of innate immune response. After evaluating several
cellular parameters (morphology, size, complexity, proliferation, cell cycle
and intracellular content of reactive oxygen species), the action of MBG-75S
particles and NanoMBG-75S on the polarization of these macrophages towards the
proinflammatory (M1) or reparative (M2) phenotype was determined by the
expression of specific M1 (CD80) and M2 (CD206, CD163) markers. We previously
measured the adsorption of albumin and fibrinogen on MBG-75S particles and the
production of proinflammatory cytokines as TNF-{\alpha} and IL-6 by macrophages
in response to these particles. This comparative study demonstrates that
particles of mesoporous bioactive glass MBG-75S and mesoporous nanospheres
NanoMBG-75S allow the appropriated development and function of RAW 264.7 and
J774A.1 macrophages and do not induce polarization towards the M1
pro-inflammatory phenotype. Therefore, considering that these mesoporous
biomaterials offer the possibility of loading drugs into their pores, the
results obtained indicate their high potential for use as drug-delivery systems
in bone repair and osteoporosis treatments without triggering an adverse
inflammatory response.
