However, interestingly, during the early stages of ALI treatment, a relatively high proportion of BMSCs differentiated into AT2 cells, and a significant increase in the number of AT2 cells in the lung tissue was observed in the BMSC group on the second and sixth days after BMSC treatment, along with an increase in SPC and AQP5 protein expression at various time points. Here, AQP5 is linked to acute respiratory distress syndrome.