Neutrophil extracellular traps (NETs) are characterized as extracellular DNA fibers comprised of histone and granular proteins. NETs play a crucial role in defense against systemic infections, inflammation, autoimmune disorders and cancer. However, excessive NETs release can increase inflammatory processes and tissue damage. Mesenchymal stromal cells (MSCs) are a promising therapy to mitigate immune dysfunctions. MSCs behavior can be influenced by culture conditions. However, the ability of -MSCs cultured in two-dimensional (2D) or three-dimensional (3D) conditions to halt NETs has not yet been investigated. The aim of this study is to evaluate the ability of MSCs, under 2D or 3D culture, to reduce NETs formation. MSCs surface markers were analyzed by flow cytometry in MSC 2D and 3D respectively: CD44+ (98.75%; 95.98%), CD49e+ (99.77%; 93.71%), CD11b- (5.86%; 2.51%) and CD19- (3.75%; 1.39%). Cell viability was assessed by Annexin/PI assay in MSC 2D and 3D respectively: live cells (71.58%; 85.62%), late apoptotic cells (10.07%; 4.70%), early apoptotic cells (8.78%; 4.59%) and necrotic cells (9.55%; 5.08%). 3D MSC spheroid morphology was characterized by diameter 201.0 ± 24.3 μm, area 32.174 ± 7.525 μm², volume 3.98x106 ± 1.28x106 µm³, perimeter 738.5 ± 108.4 μm, solidity 0.94 ± 0.02, sphericity 0.86 ± 0.04 and convexity 0.91 ± 0.03. Then, neutrophils were isolated from peritoneal lavage fluid of C57BL/6 male mice (25-30g/ 6-12 weeks) (CEUA180/19) for in vitro studies in four groups: neutrophils (NE), neutrophils incubated with 20 µg/mL of lipopolysaccharide (NE+LPS), neutrophils incubated with LPS and 2D MSCs (NE+LPS+MSC2D), or with 3D dissociated MSCs (NE+LPS+MSC3Dd). The incubation time was 1h30m in all groups. The proportion of neutrophils/MSCs was 10:1. Picogreen assay was used to analyze fluorescence intensity of cell-free DNA (cf-DNA) . Cf-DNA was significantly higher in NE+LPS group compared to NE (223.2 ± 25.81 vs 182.0 ± 38.05, respectively, p=0.0287), indicating LPS was a good inductor of NETs. 2D MSCs treatment did not mitigate cf-DNA compared to NE+LPS (200.2 ± 52.71 vs 223.2 ± 25.81, respectively, p>0.9999). However, 3D dissociated MSCs treatment was able to decrease cf-DNA in comparison to NE+LPS (87.61 ± 47.93 vs 223.2 ± 25.81, respectively, p<0.0001). In conclusion, compared to 2D cultivation, 3D cultured dissociated MSCs seems to be more efficient in mitigating in vitro LPS-induced NET formation.