Objective To observe the effects of transplantation of mesenehymal stem cells (MSCs) on pathological changes of rats with pulmonary emphysema and changes in levels of inflammatory factors in the serum and lung tissues. Methods Twenty-four female SD rats were randomly divided into three groups: the control group, emphysema group and trans-plantation group, 8 per group. Rat models of emphysema were established by fumigation in the emphysema group and trans-plantation group. Rats in the control group were fed routinely. MSCs were injected into recipient rats of transplantation group. Eight weeks after transplantation of MSCs, lung fissure sections were made to study the morphological alterations, mean alveolar numbers (MAN) and mean linear intercept (MLI) were calculated. The inflammatory factors in the serum and lung tissues were analyzed by using protein chip technique and differently expressed inflammatory factors were screened. Results In the transplantation group, 8 weeks after transplantation, MSCs can be observed in the lung tissues. Emphysematous changes of lung tissues were observed in both emphysema group and transplantation group. Emphysematous changes in transplantation group were more serious than that of the emphysema group. Significant difference was found in MLI and MAN of lung tissues in the transplantation group as compared with that of the other two groups (all P<0.05). The differently expressed inflammatory factors were ciliary neurotrophic factor (CNTF), nerve growth factor (NGF), IL-10, activin A, chemokine CX3 and leptin in the lung tissues between the emphysema group and control group;and the differently expressed inflammatory factors were CNTF, IL-10 and TNF-α in the lung tissues between the transplantation group and emphysema group. The levels of CNTF in the lung tissues were statistically different among these three groups (all P<0.05). The differently expressed inflammatory factors in the serum were CNTF, IL-1β, IL-2, IL-4 and IL-6 between the emphysema group and control group; and the differently expressed inflammatory factors in the serum were IL-1β, IFN-γand IL-10 between the transplantation group and the emphysema group.The levels of IL-1β were statistically different among these three groups (all P<0.05). Conclusions MSCs transplantation can effectively alleviates the pathological changes of pulmonary emphysema in rat models, whose mechanism may be involved in down-regulating the expression of inflammatory factor. [ABSTRACT FROM AUTHOR]