Human peripheral blood CD34+cells attenuate oleic acid-induced acute lung injury in rats

Background aims. Adult stem cell based therapy is a promisinghovel approach for treatment of acute lung injury (ALT). In this study, we evaluated the therapeutic effect of isolated human peripheral blood CD34+ progenitor cells in an ALT rat model, induced by oleic acid (OA) injection. Methods. Seventy-five adult female rats were used in this study. Group A, control without treatment, and group B, control injected with phosphate-buffered saline, comprised 15 rats each; the remaining 45 rats were injected with OA to induce ALT and were further subdivided into 3 groups: group C (ALT group, 15 rats), group D (ALT and fibroblast group, 15 rats) and group E (ALI and CD34+ cell group, 15 rats). Results. CD34+ cells transplantation in rats with OA-induced lung injury improves the arterial PaO2 and wet/dry ratio, reduces infiltration of inflammatory cells and decreases lung vascular permeability as determined by reduced intra-alveolar and interstitial patchy congestion and hemorrhage as well as decreased interstitial edema. Additionally, lung inflammation determined by expression of the pro-inflammatory mediators intercellular adhesion molecule 1 and tumor necrosis factor-a was attenuated in CD34+ cell treated rats at 6, 24 and 48 h post-OA challenge compared with non-treated rats. Moreover, the expression of anti-inflammatory molecule interleukin-10 was up-regulated in the lung of OA-induced All rats after administration of CD34+ cells. The important finding was that human TNF-alpha-induced protein 6 (TSG-6) gene expression was significantly up-regulated in rats treated with CD34+ cells. Conclusions. The freshly isolated human peripheral blood derived CD34+ cells may be used as an important source of stem cells that improve ALT. The anti-inflammatory properties of CD34+ cells in the lung are explained, at least in part, by activation of CD34+ cells to express TSG-6.