Laser-Modified Ti Surface Improves Paracrine Osteogenesis by Modulating the Expression of DKK1 in Osteoblasts.

Titanium surface modifications are widely used to modulate cellular behavior by recognition of topographical cues. However, how those modifications affect the expression of mediators that will influence neighboring cells is still elusive. This study aimed to evaluate the effects of conditioned media from osteoblasts cultured on laser-modified titanium surfaces on the differentiation of bone marrow cells in a paracrine manner and to analyze the expression of Wnt pathway inhibitors. Mice calvarial osteoblasts were seeded on polished (P) and Yb:YAG laser-irradiated (L) Ti surfaces. Osteoblast culture media were collected and filtered on alternate days to stimulate mice BMCs. Resazurin assay was performed every other day for 20 days to check BMC viability and proliferation. After 7 and 14 days of BMCs maintained with osteoblasts P and L-conditioned media, alkaline phosphatase activity, Alizarin Red staining, and RT-qPCR were performed. ELISA of conditioned media was conducted to investigate the expression of Wnt inhibitors Dickkopf-1 (DKK1) and Sclerostin (SOST). BMCs showed increased mineralized nodule formation and alkaline phosphatase activity. The L-conditioned media enhanced the BMC mRNA expression of bone-related markers Bglap, Alpl, and Sp7. L-conditioned media decreased the expression of DKK1 compared with P-conditioned media. The contact of osteoblasts with Yb:YAG laser-modified Ti surfaces induces the regulation of the expression of mediators that affect the osteoblastic differentiation of neighboring cells. DKK1 is among these regulated mediators.

Preadministration of yerba mate (Ilex paraguariensis) helps functional activity and morphology maintenance of MC3T3-E1 osteoblastic cells after in vitro exposition to hydrogen peroxide.

Natural substances with antioxidant effects may benefit prevention and treatment of people with or prone to bone diseases after menopause, such as osteoporosis. This study aimed to evaluate the in vitro effect of preadministration of yerba mate extract (YM) in the metabolism of MC3T3-E1 osteoblasts exposed to hydrogen peroxide (H2O2). The cells (MC3T3-E1) were cultured in 24-well plates with the concentration of 1 µg/mL yerba mate extract dissolved in culture medium throughout the culture period. Four hours before each experiment, 400 µmol/L H2O2 was added per well to simulate oxidative stress. There were evaluated cell adhesion and proliferation, in situ detection of alkaline phosphatase (ALP), mineralized nodules, and immunolocalization of osteocalcin (OCN), bone sialoprotein (BSP) and alkaline phosphatase (ALP) proteins. The results showed that YM preadministration to H2O2 exposition significatively increased cell adhesion after 3 days as well as proliferation and in situ ALP detection after 10 and 7 days respectively, when compared to H2O2 group. Besides, staining of OCN and BSP proteins was less intense and scattered in poor spread cells with cytoskeletal changes in H2O2 group when compared to control and YM H2O2 group. ALP staining was restrained to intracellular regions and similar in all experimental groups. Our results suggest that preadministration of yerba mate extract may prevent deleterious effects in the morphology and functional activity of osteoblasts exposed to H2O2, which could enable the maintenance of extracellular matrix in the presence of oxidative stress.