Nano-TiO2 inhibit cytotoxicity and osteogenic differentiation of CXCR4-transfected bone marrow mesenchymal stem cells

Mesenchymal stem cells (MSCs) are applied to clinical practice. Nanometer titanium dioxide (Nano-TiO2) is a type of biological material with great biocompatibility. Herein, we aimed to explore Nano-TiO2’s effects on differentiation of bone marrow MSCs (BMSCs) after transfection with CXCR4. After transfection of CXCR4 to BMSCs, we cultured BMSCs in medium containing 70 nm and 100 nm Nano-TiO2. At the same time, BMSCs without CXCR4 transfection were cultured using 100nm Nano-TiO2 medium and set as NC group. Then the cytotoxicity was detected by MTT assay, followed by ALP staining. Western blot and RT-qPCR were conducted to determine Runx2 and BGP expression. Application of TiO2 (70 nm and 100 nm) decreased the viability of BMSCs (P < 0.05) and ALP activity, while ALP activity of 70 nm group was markedly greater than that of 100 nm group. After BMSCs were cultured for 7 d and 14 d, lower expression of Runx2 and BGP was noticed in BMSCs of 100 nm group relative to 70 nm group (P < 0.05), accompanied with lower CXCR4 mRNA expression. In conclusion, Nano-TiO2 exhibited inhibitory effects on CXCR4-transfected BMSCs in a participle size-dependent manner. Increased size of nanoparticles was associated with decreased viability and greater cytotoxicity.