Background: In regenerative medicine, cell-free therapy has emerged as a promising new method over the past decade. The dental mesenchymal stem cells (MSCs) secretome has been considered an innovative therapeutic biological strategy capable of modulating cellular crosstalk and functionality for enhanced tissue regeneration. The purpose of the study is to evaluate the functionality of the secretome isolated from either gingiva (GSCs) or human dental pulp (hDPSCs) in healing a critical-sized tibial bone defect in a rabbit model.
Methodology: Twenty New Zealand white rabbits were used to induce four critical-sized bone defects in their tibiae (two defects in each tibia). Bone defects in each rabbit were randomized into four groups. Group 1: The defects were left empty. Group 2: The defects were filled with collagen scaffold only. Group 3: The defects were filled with collagen scaffold loaded with hDPSCs’ secretome. Group 4: The defects were filled with collagen scaffold loaded with GSCs’ secretomes. Six rabbits underwent sequential fluorescent labeling and were euthanized at day 56 for detecting mineral apposition rate. The other 14 rabbits were divided into two groups according to the euthanized dates (28 and 56 days) for the histologic, histomorphometric evaluation, and RT-PCR to measure osteocalcin gene expression.
Results: The histological, histomorphometric, and fluorescent microscopic analysis revealed that dental pulp MSCs secretome enhanced the new bone formation process compared to gingival MSCs. In addition, osteocalcin expression was higher in dental pulp MSCs secretome.
Conclusion: Dental MSCs secretomes, particularly from dental pulp MSCs, appear to be a promising therapeutic strategy for promoting bone tissue repair and regeneration in future clinical applications.
Keywords: Secretome, dental pulp MSCs, gingival MSCs, critical-sized bone defect.