This study aimed to evaluate periosteum-derived mesenchymal stem cells (P-MSCs) cultured under simulated microgravity (SMG) conditions. P-MSCs were induced toward osteogenic differentiation and then exposed to SMG for up to 48 h. As a control, P-MSCs were maintained under identical conditions but without SMG exposure. Cell viability, osteogenesis-related analytes, and gene expression were analyzed at 3, 24 and 48 h. Cell viability under SMG was lower after 3 h but was significantly higher after 24 h, with no difference at 48 h. There was a higher expression of pathways associated with inflammation at 3 h, which was attenuated by 24 h and neutralized at 48 h. P-MSCs under SMG demonstrated three characteristics in at least one timepoint, which supports a pro-osteogenic signaling response: (1) higher osteoprotegerin levels; (2) lower DKK1 and TNF levels; (3) upregulation of genes related to osteogenesis. Our data suggest that P-MSCs exhibit enhanced pro-osteogenic regulatory modulation in SMG.

Periosteum-derived osteo-like cells (PDOCs) and their lyophilized conditioned medium are promising tools for bone regeneration, but their therapeutic potential for osteoporosis remains unknown. This study evaluated the effects of PDOCs and their lyophilized conditioned medium on bone mineralization and microarchitecture in ovariectomized rats. Eighteen ovariectomized rats (six animals per group) received PBS (negative control group—NCG), PDOCs (periosteum osteo-like cell group—POCG), or a PDOC lyophilized conditioned medium (periosteum osteo-like lyophilized conditioned medium Group—POCM). All animals were euthanized after 42 days, and the femurs were submitted to microCT and histomorphometric analysis to determine: (1) thickness of the cortical bone; (2) number of trabeculae; (3) percentage of mineralized tissue; (4) percentage of collagen fibers; and (5) percentage of medullary spaces. The thickness of the cortical bone was statistically higher in POCG and POCM than in NCG animals (p < 0.05). The trabecular number was higher in POCG and POCM than in NCG rats (p < 0.05). The percentage of mineralized tissue was higher in POCG and POCM than in NCG animals (p < 0.05). No statistically significant difference was observed for collagen fibers or percentage of medullary spaces among groups. The use of PDOCs and their lyophilized conditioned medium improved cortical bone thickness, the number of trabeculae, and the level of mineralized tissue, suggesting that tissue engineering approaches with PDOCs and their lyophilized conditioned medium have potential use for the treatment of osteoporosis.

Periosteum-derived osteo-like cells (PDOCs) and their lyophilized conditioned medium are promising tools for bone regeneration, but their therapeutic potential for osteoporosis remains unknown. This study evaluated the effects of PDOCs and their lyophilized conditioned medium on bone mineralization and microarchitecture in ovariectomized rats. Eighteen ovariectomized rats (6 animals per group) received PBS (Negative Control Group–NCG); PDOCs (Periosteum Osteolike Cell Group - POCG), or PDOCs lyophilized conditioned medium (Periosteum Osteolike lyophilized conditioned medium Group - POCM). All animals were euthanized after 42 days, and the femurs submitted to microCT and histomorphometric analysis to determine: (1) thickness of the cortical bone; (2) number of trabeculae; (3) percentage of mineralized tissue; (4) percentage of collagen fibers; and (5) percentage of medullary spaces. The thickness of the cortical bone was statistically higher in POCG and POCM than in NCG animals (p<0.05). The trabecular number was higher in POCG and POCM than in NCG rats (p<0.05). The percentage of mineralized tissue was higher in POCG and POCM than in NCG animals (p<0.05), and no statistically significant difference was observed for collagen fibers and percentage of medullary spaces among groups. The use of PDOCs and their lyophilized conditioned medium improved cortical bone thickness, the number of trabeculae and the level of mineralized tissue, suggesting that tissue engineering approaches with PDOC and their lyophilized conditioned medium have potential use for the treatment of osteoporosis.

Critical bone defects present significant clinical challenges due to their debilitating nature and associated costs. Tissue engineering offers a promising solution, employing biomaterials like porous chitosan (CH) and xanthan gum (XG) membranes as scaffolds for tissue regeneration. Electrical stimulation (ES) and laser (L) therapy, known for osteogenic and anti‐inflammatory effects, respectively, may synergistically enhance bone healing when combined with these membranes. This study evaluated CH/XG membranes and their association with ES and L for the treatment of critical bone defects (25 mm ² ) created in 80 male Wistar rats. The animals were divided into four groups: untreated, CH/XG, CH/XG + ES, and CH/XG + L, assessed at days 30 and 90. Histomorphometric and real‐time PCR analyses revealed greater tissue and blood vessel formation in the CH/XG, CH/XG + ES, and CH/XG + L groups compared to the untreated group. At day 30, reduced Runx‐2 and Osx expression in the treated groups suggested an initial high inflammatory response. The CH/XG group showed pronounced inflammation (elevated Il‐1β and pro‐inflammatory markers) alongside an anti‐inflammatory response. Conversely, compared with the CH/XG‐only group, the CH/XG + ES and CH/XG + L groups generally showed lower expression of the evaluated pro‐inflammatory markers after 30 days, together with treatment‐ and time‐dependent changes in anti‐inflammatory markers. Although inflammation limited the initial effectiveness of CH/XG membranes, significant positive impacts were observed after 90 days. Combining membranes to cover bone defects and adjunctive therapies, as demonstrated in this study, emerges as a beneficial approach for enhancing bone repair outcomes. Adding osteoconductive or osteoinductive fillers may bring further healing improvements.