OBJECTIVETo investigate the effect of intravenous bone marrow-derived mesenchymal stem cell (MSC) transplantation for early intervention of lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice.

METHODSThirty-six mice were randomized into control group, PBS-treated ALI group, and MSC-treated ALI group. In the latter two groups, mouse models of ALI were established by intranasal instillation of LPS, and 1 h later, the 4th passage of MSCs isolated from the bone marrow of mice or PBS were administered via the tail vein. The histological findings, lung wet/dry (W/D) weight ratio, neutrophil count and protein and cytokine contents in the bronchoalveolar lavage fluid (BALF), and myeloperoxidase (MPO) level in the lung tissue were analyzed at 24 h after MSC administration. Engraftment of MSCs in the recipient lung was determined by fluorescent PKH26 staining and flow cytometry.

RESULTSCompared with the control group, PBS-treated ALI group showed significantly higher protein levels, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and neutrophil count in the BALF and MPO content in the lung tissue, with also severe damage of lung histology. MSCs administration significantly reduced the lung W/D weight ratio, the levels of protein, TNF-α, IL-6 and neutrophil count in the BALF and MPO content in the lung tissue, and obviously lessened the lung injury 24 h after the transplantation. MSC administration also significantly increased the level of IL-10 in the BALF.

CONCLUSIONIntravenous MSC transplantation can effectively improve the lung histology, attenuate the inflammatory response, reduce pulmonary edema in the early stage of LPS-induced ALI in mice, and such effects are independent of MSC engraftment in the lungs.