ABSTRACT
This study aimed to verify the efficacy of low-level laser irradiation (LLLI) on the proliferation of MC3T3-E1 preosteoblasts cultured on poly(lactic acid) (PLA) films. The produced films were characterized by contact angle tests, scanning electron microscopy (SEM), atomic force microscopy, differential scanning calorimetry, and X-ray diffraction. The MC3T3-E1 cells were cultured as three different groups: Control-cultured on polystyrene plastic surfaces; PLA-cultured on PLA films; and PLA + Laser-cultured on PLA films and submitted to laser irradiation (660 nm; 30 mW; 4 J/cm2 ). Cell proliferation was analyzed by Trypan blue and Alamar blue assays at 24, 48, and 72 h after irradiation. Cell viability was assessed by Live/Dead assay, apoptosis-related events were evaluated by Annexin V/propidium iodide (PI) expression, and cell cycle events were analyzed by flow cytometry. Cell morphology on the surface of films was assessed by SEM. Cell counting and biochemical assay results indicate that the PLA + Laser group exhibited higher proliferation (p < 0.01) when compared with the Control and PLA groups. The Live/Dead and Annexin/PI assays indicate increased cell viability in the PLA + Laser group that also presented a higher percentage of cells in the proliferative cell cycle phases (S and G2/M). These findings were also confirmed by the higher cell density observed in the irradiated group through SEM images. The evidence from this study supports the idea that LLLI increases the proliferation of MC3T3-E1 cells on PLA surfaces, suggesting that it can be potentially applied in bone tissue engineering.
Subject(s)
Low-Level Light Therapy , Osteoblasts/cytology , Osteoblasts/radiation effects , Polyesters/pharmacology , Animals , Apoptosis/drug effects , Apoptosis/radiation effects , Cell Cycle/drug effects , Cell Cycle/radiation effects , Cell Proliferation/drug effects , Cell Proliferation/radiation effects , Cell Shape/drug effects , Cell Shape/radiation effects , Cells, Cultured , Crystallization , Mice , Microscopy, Atomic Force , Osteoblasts/drug effects , X-Ray DiffractionABSTRACT
Introduction: Tissue engineering aims at the development of biological substitutes that can restore, maintain, or improve the functionality of damaged tissue or organs. To this end, molecular and cellular interactions may influence the tissue reactions to biomaterials. In order to be effective and integrated to the receiving area, the bone graft is required to allow a strong cell adhesion, interacting with several molecules to induce migration, differentiation, and thus the mineralization of the new bone on the graft. These cell adhesion molecules (CAM) will mediate the contact between two cells or between cells and the extracellular matrix, an essential process to the success of the implant. Objective: This paper is a systematic review of the literature on the mechanisms of cell adhesion to bone grafts associated to nanotechnology, describing the importance and the role of those molecules in the adhesion and thus in tissue regeneration. Literature review: After the use of search strategies, 18 articles that describe processes of cell adhesion to bone grafts were selected. Results: The main reported mechanisms involve cell adhesion molecules (CAMs) and extracellular matrix components. Conclusion: Several molecules are involved in the process of cell adhesion to bone grafts, highlighting the role of integrins, the focal adhesion mechanism, the influence of the collagen matrix, and the activity of alkaline phosphatase in bone matrix formation. Accurate identification of these mechanisms of cell adhesion is essential for further advancement in tissue engineering, such as the production of biological bone substitutes that achieve a better clinical outcome.
