Effects Of Caudal Vein Injection Of LR-MSCs On Airway Inflammation And Airway Hyperresponsiveness In Asthmatic Mice

Objective: Airway inflammation and airway hyperresponsiveness are two important pathophysiological features of bronchial asthma.Previous studies have found that mesenchymal stem cells have an effective therapeutic effect on asthma.Therefore,through the isolation,culture and identification of mouse lung mesenchymal stem cells(LR-MSCs),this research is aim to investigate the caudal vein injection of LR-MSCs on airway inflammation and airway hyperresponsiveness of murine model of acute asthma,to seek new ways for the treatment of asthma.Methods: Sca-1+CD31-CD45-cell mass which is proved to be LR-MSCs is isolated from mouse lung tissue suspension cells using cell sorting flow cytometer and cultured in vitro.Then passaged LR-MSCs was analysised of the surface markers of mesenchymal stem cells by flow cytometry.An acute asthma model was established by intraperitoneal injection and repeated inhalation of ovalbumin and at the same time the control group was established by PBS.Through the caudal vein injection of LR-MSCs to intervent acute asthma model to establish LR-MSCs intervention group and in the meantime LR-MSCs control group was established by PBS.The Penh value of airway hyperresponsiveness in each group of mice was measured by BUXCO noninvasive lung function detector.BALF was obtained by bronchoalveolar lavage,and then count the number of BALF total cells,neutrophil cells,eosinophil cells and monocyte cells.The expression of Th2 type inflammatory cytokines IL4,IL-5,IL-13 in BALF in each group of mice were measured simultaneously.The levels of inflammatory factors OVAsIgE and OVAsIgG1 in serum of mice were determined by ELISA.HE staining was used to observe the histological changes and inflammatory infiltration.Results:(1)Successfully isolated and cultured LR-MSCs in vitro,and LR-MSCs have positive expression of CD29,Sca-1,negative expression of CD31 and CD45,in line with the expression of surface markers of mesenchymal stem cells.(2)By ovalbumin sensitization and excitation,we successfully established acute asthma model,that means airway hyperresponsiveness Penh value and Th2 cytokine IL-4,IL-5,IL-13 in BALF and the number of BALF total cells,neutrophil cells,eosinophil cells and monocyte cells count and the levels of inflammatory factors OVAs IgE and OVAs IgG1 in serum in asthmatic model group were all significantly higher than the normal control group.Meanwhile,there was a large number of inflammatory cells infiltration in bronchial wall and blood vessels in the asthmatic model group than in the normal control group.(3)LR-MSCs intervention by caudal injection of LR-MSCs can effectively reduce airway hyperresponsiveness and airway inflammation level.That means airway hyperresponsiveness Penh value and Th2 cytokine IL-4,IL-5,IL-13 in BALF and the number of BALF total cells,neutrophil cells,eosinophil cells and monocyte cells count and the levels of inflammatory factors OVAs IgE and OVAs IgG1 in serum in LR-MSCs intervention group was significantly lower than the asthmatic model group.Meanwhile,there was no significant inflammatory cells infiltration in bronchial wall and blood vessels in the LR-MSCs intervention group than in the asthmatic model group.At last,there was no significant difference between the normal control group and the LR-MSCs control group in airway hyperresponsiveness and airway inflammation.Conclusion:(1)Successfully isolated the Sca-1+CD31-CD45-cell mass and verified that Sca-1+CD31-CD45-cell mass are LR-MSCs.(2)To some extent,LR-MSCs intervention can reduce airway inflammation and airway hyperresponsiveness in asthma,and it is expected to be a new way to treat asthma.