Bone Marrow-derived Mesenchymal Stem Cells To The Formation Mechanism Of Repair Of Bleomycin Caused Lung Injury And Its Inhibition Of Fibrosis

Mesenchymal stem cells (MSC) are a sub-population of stem cells that can beisolated from various adult tissues. They are reported to have the potential todifferentiate into cells of all three layers and home to injured tissue positionand repair the injured part. There are a number of reports saying that bonemarrow-derived MSC could facilitate the repair of lung injury while themechanisms involved in the process are yet to be investigated. Here we used ableomycin-induced lung injury model to observe the effect of eGFP-labeledallogenetic MSC on the treatment of injury and discuss the relatedmechanisms. Results show that MSC injected immediately after bleomycininjury could effectively ameliorate the inflammatory reaction both in the acuteand chronic injury stage, prevent the development of fibrosis. Engrafted MSCwere shown to distribute mainly in bronchial epithelium, alveolar epithelialand interstitial part with low engraftment rate. The TH1 and TH2 cell factorlevels in the spleen of model and treated mice were examined by use of FACS.Results show that in the fibrosis rapid on set stage, injected MSC couldup-regulate TH1 factor and down-regulate TH2 factor, adjusting theTH2-ruled microenvironment to a microenvironment ruled by TH1. Thus weconsider the modulation of MSC to the TH1/TH2 balance to be one of the mechanisms involved in their repair of lung injury and prevention of fibrosis.