Effects of different concentrations of mesenchymal stem cells treatment on LPS-induced acute respiratory distress syndrome rat model.

Purpose: This study was prospectively designed to investigate the effects of different concentrations of mesenchymal stem cells treatment on respiratory mechanics, oxygenation, hemodynamics and inflammatory response in LPS-induced acute respiratory distress syndrome (ARDS) rat model. Methods: One hundred and twenty six LPS-induced ARDS model rats (weighted 200-220 g) were randomly divided into three groups: 1) Control group (N = 42); 2) low-dose hUC-MSC treatment group (MSC group 1, 1x10⁷ cell/kg, N = 42); 3) high-dose hUC-MSC treatment group (MSC group 2, 2x10⁷ cell/kg, N = 42), sham operation group as healthy group (N = 15). The rats were observed closely for 24 hours after hUC-MSC treatment, and the survival rate was calculated. At 24 hours, all rats were tested for hemodynamics, blood gas analysis, heart, lung, liver and kidney functions, inflammatory factors detection in blood samples and broncho-alveolar lavage fluid (BALF). The lung tissue of the rats was collected for HE staining analysis. Results: After LPS injection, ARDS was obvious in all LPS-infused rat groups, consistent with severe acute lung injury and high death rate. However, compared with the control group, a single intravenous injection hUC-MSC at dose of 1 × 10⁷ cells/kg (low dose group) and 2 × 10⁷ cells/kg (high dose group) reduced the mortality of rats with LPS-induced ARDS, as well as improving the lung function, increased the arterial oxygen pressure, improved the heart function, and reduced the levels of inflammatory factors including IL-1β, IL-6, and TNF-α. In addition, the high dose MSC group showed better lung injury therapeutic effects than the low dose MSC group. Data from this study demonstrated that injection of hUC-MSC had a significant therapeutic effect in treating the rat model of LPS-induced ARDS and multiple organ function injury.