Heightened anti-inflammatory and antioxidant effects of bone marrow stem cell-conditioned media with mono and doped TiO2 nanoparticles in Carrageenan-induced inflammation

Inflammation and oxidative stress are key mediators of tissue damage in numerous pathological conditions. This study investigated the anti-inflammatory and antioxidant effects of titanium dioxide nanoparticles (TiO₂ NPs), mono-doped TiO₂ (Cu), and dual-doped TiO₂ (Cu/Zn) in a carrageenan-induced paw edema model. TiO₂ nanoparticles were synthesized and characterized by XRD, SEM, TEM, DLS, and EDX, confirming an anatase crystalline phase, spherical morphology, and uniform size distribution with successful dopant incorporation. Bone marrow mesenchymal stem cells (BM-MSCs) were isolated and characterized by flow cytometry (CD90⁺, CD73⁺, CD34⁻, CD45⁻) and trilineage differentiation, and their conditioned media (CM) were used for therapeutic application. A pre-study screening using three doses (10, 20, and 50 mg/kg) demonstrated a dose-dependent reduction in paw edema, with the 50 mg/kg dose showing the highest inhibition, comparable to indomethacin. The main experiment comprised six groups: control, carrageenan, indomethacin, TiO₂ CM, Cu-TiO₂ CM, and Cu/Zn-TiO₂ CM. Carrageenan administration elevated TNF-α, IL-6, IL-4, COX-2, and 5-LOP while reducing IL-10, alongside increased oxidative stress markers (MDA and NO) and decreased antioxidant defenses (CAT, SOD, GPx, and TAC). Treatment with TiO₂ formulations markedly reversed these effects in a dose-dependent manner. Dual-doped TiO₂ combined with BM-MSC-CM produced the greatest improvement, normalizing cytokine profiles, reducing lipid peroxidation and nitric oxide levels, and restoring antioxidant enzyme activities. Histopathological assessment confirmed these findings, showing nearly normal dermal architecture with minimal inflammatory infiltration. The results highlight the synergistic therapeutic potential of doped TiO₂ nanoparticles and BM-MSC-CM in mitigating inflammation and oxidative stress.