The Study Of Increasing BMSCs Transfected By CXCR4 Gene Homing To The Injured Lungs Induced By Seawater Drowning

With the development of ocean shipping industry, the seaside tourism, marine aquaculture industry and the growth of offshore activities, the number of seawater drowning personnel in our country has been increasing. At the same time, seawater drowning also frequently occurred in military maritime training and battle. Compared with freshwater drowning, lung’s direct and secondary injury in seawater drowning is more severe because of the special physical and chemical properties of seawater such as hypertonicity, which will ultimately develop into Seawater respiratory distress syndrome(SW-RDS). SW-RDS is a dangerous ill. We should support mechanical ventilation to ill lung as early as possible. The mortality of SW-RDS is still in a high level even given positive rescue. All countries in home and abroad have made deep research in this model for seeking new treatments. Nowadays, there were a large number of SW-RDS animal models established, but much of them lack of stability and survival time was short, which adverse to the follow study. Therefore we try to establish a stable model as well as ensure the animals’ survival time and tracking stem cell homing to the injured lungs induced by seawater drowning with Dir-BMSCs and Dir-CXCR4-BMSCs which stained by Dir fluorescent dyes. 【Objective】 Establish a stable seawater drowning rats’ model, and tracking Dir-BMSCs and Dir-CXCR4-BMSCs transfected by lentivirus homing to the lungs in SW-RDS model. 【Methods】 1 Establish the rat models induced by seawater drowning 40 rats were randomly divided into 4 groups(n=10), control groups(C) and seawater drowning groups(S1、S2、S3). The rats were given intratracheally 0 ml/kg、2 ml/kg、2.5 ml/kg、3 ml/kg of seawater. Observe the rats’ respiratory rate and draw blood via right common carotid artery to have blood gas analysis, calculate the oxygenation index in 5 time points which include 0min、0.5h、1h、2h、4h after the model established. Choose group C and S3 to measure the W/D ratio of right lung lobes at 4h time point, and to observe the lung lobes’ morphological characteristics and made pathological scores to the rats’ right lung lobes. 2 To culture, transfect and stain rat BMSCs and observe them homing to the lungs in SW-RDS model Choose SD rats weighted 60~80g, separated their femur and tibia. Then isolate and culture rat bone marrow mesenchymal stem cells by using density gradient centrifugation combined with bone marrow adherent separation method. Use 4th generation BMSCs to appraisal analysis. Send them to a stem cell laboratory located in Fuzhou General Hospital of Nanjing Military Region to construct Dir-BMSCs and Dir-CXCR4-BMSCs. 20 rats were randomly divided into 2 groups(n=10), control group(Dir-BMSCs injection in tail intravenous after the model established) 、experimental group(Dir-BMSCs injection in tail intravenous after the model established). Observe the BMSCs homing to the lungs in SW-RDS model at 4h time point after the model established. 【Results】 1 After the models established, the respiratory rate in group S3 was faster than control groups(P<0.05). The rats in group S3 have been suffered serious acidosis, hypercapnia and hyoxemia. The oxygenation index in 0-0.5h time point was reaches the standard of moderate ARDS; in 0.5-4h time point was reach the standard of mild ARDS. Compared with control groups, the W/D ratio and pathological scores of right lung lobes in group S3 all have statistical differences(P<0.05) at 4h time point. What’s more, compared with posterior lobe, the W/D ratio and pathological scores of anterior lobe, middle lobe and accessory lobe all have statistical differences(P<0.05). 2 The rat BMSCs isolated and cultured in our experiment with high purity, and the cells are all fusiform shape, surface antigen profiles were positive for CD 29, CD 90 and negative for CD34, CD45. They also can be induced into adipocytes. Stem cells homing to the injured lungs induced by seawater drowning are not uniform. Compared with the control group, the ROI relative ratio of lungs in experimental group have statistical differences(P<0.05) at 4h time point. 【Conclusion】 1 The SW-RDS rat model can be successfully established by perfusion of seawater in 3ml/kg dosage into rats. In the model, the right lung posterior lobe suffered the most seriously injury. 2 Stem cells can homing to the injured lungs induced by seawater drowning, and BMSCs transfected by CXCR4 gene homing to the injured lungs are higher than normal BMSCs.