MicroRNAs-26 and related osteogenic target genes can play a pivotal role in improving the mechanical and cellular properties of critical-sized foot defects in photobiomodulation and adipose-derived stem cell-based treatments in a rat model

Abstract Photobiomodulation (PBM) and stem cell-based treatments are relatively invasive methods for treating bone defects. Specific and oriented cellular and molecular functions can be induced by applying an appropriate type of PBMT and ADSs. This study aimed to explore the role of MicroRNAs in the PBM & hADS-based treatments in improving the mechanical and cellular properties of a critical size fracture in a rat model. A critical size femoral defect (CSFD) is induced in both femoral bones of 24 rats. Then a human demineralized bone matrix scaffold (hDBMS) was engrafted into the CSFDs of all rats. Experiments are performed on 4 groups (12 rats per group): (1) Control (hDBMS); (2) hDBMS + hADS, hADS was engrafted into CSFDs; (3) hDBMS + PBM, the CSFD was exposed to PBM(810 nm wavelength, 1.2 J/cm2 energy density); (4) hDBMS+(hADS + PBM), hADSs were implanted into CSFD then were exposed to PBM. At 42 days after CSFD induction, the rats were killed and, the left and right CSFDs were removed for the mechanical compression tests, and molecular and cellular studies, respectively. The results indicate that miRNA-26a, BMP, SMAD, RUNX, and OSTREX were more expressed in the treated groups than in the control group. Furthermore, the biomechanical and histological properties of CSFDs in treated groups were better than the control group. The correlation tests revealed a positive relationship between microRNA and improving biomechanical and cellular parameters of CSFDs in the rat model. We concluded that MicroRNA-26 plays a significant role in the hADS, PBM, and hADS + PBM-based healing of CSFDs in rats.