Effect Of Human Adipose Tissue-derived Stem Cells On Acute Lung Injury Of Rat Lung

Background: Acute lung injury is commonly developed with sepsis, increasedvascular permeability and alveolar flooding as pathophysiology. Acute lung injury is aleading cause of significant morbidity and mortality. Especially it’s a syndrome as lotsof kinds of diseases severe form and complication. Despite advances in supportive andpharmacologic treatment, acute lung injury is also a serious problem. While the stemcells have broadly familiarized by researchers, they are implanted into and cure severalkinds of disease. So, the stem cells also play a role in attenuating acute lung injury andput into practice potential. The past decade demonstrated that mesenchymal stem cellshave the ability to participate in the repair of several kinds of injury, including acutelung injury. But the stem cells repair the blood vessel endothelium of acute lung injuryis unknown. In this study, we hypothesized that the administration of adiposetissue-derived stem cells are co-culture with rat pulmonary microvascular endothelialcells, which are exposured to lipopolysaccharide, and then test the endothelial nitricoxide synthase of the pulmonary microvascular endothelial cells. Also, we administratethe adipose tissue-derived stem cells to the rat of acute lung injury by intravenousinjection, and test the protein expression of the endothelial nitric oxide synthase in lung.Methods: I adopt the enzyme digestion of method to obtain the adiposetissue-derived stem cells. The small fragments of tissue were treated with1%collagenaseⅠ.Flow cytometry for expression of adipose tissue-derived stem cells ofcharacteristic surface markers, CD90、CD106、CD34, were determined. I adopt theperipheral lung tissue, which is isolated and cut into small fragments of tissue, to obtainrat pulmonary microvascular endothelial cells. They are identified the characteristicsurface markers Flt-1and vWF by immunofluorescence staining.In vitro, adipose tissue-derived stem cells were co-cultured with pulmonarymicrovascular endothelial cells for72hours, which have exposured to5μg/ml lipopolysaccharide for4hours. Then we measured the endothelial nitric oxide synthaseexpression in pulmonary microvascular endothelial cells. In vivo, we administrated theadipose tissue-derived stem cells through caudal vein to acute lung injury model of ratswhich induced by lipopolysaccharide (6mg/kg). After7days, we examined the lungwet-to-dry ratio, protein of endothelial nitric oxide synthase expression in lung.Result: Flow cytometry analysis demonstrated that adipose tissue-derived stemcells are positive for expression of CD90,90.6%, showed less expression for CD106,7.5%, and not expression CD34,1.8%. Immunofluorescence analysis demonstrated thatpulmonary microvascular endothelial cells were positive for expression of Flt-1andvWF. In vitro, adipose tissue-derived stem cells mediated an up-regulation theendothelial nitric oxide synthase expression in pulmonary microvascular endothelialcells. Moreover, in vivo, there was also a significant decrease in lung wet-to-dry ratio ofadipose tissue-derived stem cells-treated rats, compare to non-adipose tissue-derivedstem cells-treated rats. The adipose tissue-derived stem cells administration mediated anup-regulation of the protein of endothelial nitric oxide synthase expression in lungsignificantly, compare to non-adipose tissue-derived stem cells-treated rats.Conclusion: The adipose tissue-derived stem cells were able to improve theendothelial nitric oxide synthase in pulmonary microvascular endothelial cells. Also, theadipose tissue-derived stem cells can decreased wet-to-dry ratio (P＜0.05) andimproved the endothelial nitric oxide synthase protein expression in rat lung (P＜0.05).