Intervention And Mechanism Of Human Umbilical Cord Mesenchymal Stem Cells In Allergic Rhinitis

Allergic rhinitis(AR)is an allergic disease characterized by edema of the nasal mucosa,watery mucus,nasal itching,paroxysmal sneezing,and nasal congestion.Epidemiologic results show that on average 1～3 out of 10people suffer from different degrees of allergic rhinitis,which seriously affects patients’sleep,work and quality of life.Although this disease is not a serious threat to life,if not treated in time,it can cause some complications,such as sinusitis,asthma,conjunctivitis and other respiratory diseases,but also associated with bronchiectasis,chronic obstructive pulmonary disease,sleep apnea syndrome,nasopharyngeal cancer and other respiratory diseases.AR is mainly related to environmental factors and genetics.Avoiding exposure to allergens is the most ideal preventive measure for AR.However,it is difficult to do so in natural environment.Therefore,it is urgent to find an effective method to treat AR.Dendritic cells(DCs)have powerful antigen presenting function,and are the only professional antigen presenting cells(APCs)that can directly activate initial T cells,which plays an important role in initiating adaptive immune response.DCs in different mature states have different functions.When immature,DCs mainly plays the role of uptake and processing of exogenous antigens and participates in the induction of peripheral immune tolerance.Then DCs migrates through the input lymphatic vessels to secondary lymphatic organs,during which DCs gradually matures,plays the role of antigen presentation and stimulates the activation of initial T cells to Th1 cells and Th2 cells.Studies have shown that the number and function of DCs in normal individuals are different from those with allergic diseases.There are more mature DCs(m DCs)in allergic individuals,which presents antigen information and stimulates Th0 cells to over-activate to Th2,causing inflammation,while there are more immature DCs(i DCs)in normal individuals,which mainly plays the role of inducing immune tolerance.DCs is expected to be a new target for AR treatment.Human umbilical cord mesenchymal stem cells(h UC-MSCs)showed strong differentiation,proliferation and immunoregulatory effects.Studies have reported that h UC-MSCs have obvious immunosuppressant effects on a variety of immune cells such as monocytes and dendritic cells,which provides a theoretical basis for the treatment of other related immune system diseases.Through the intervention of human umbilical cord mesenchymal stem cells on the mouse model of allergic rhinitis,and the influence of human umbilical cord mesenchymal stem cells on the differentiation and function of dendritic cells,this study evaluated the role of human umbilical cord mesenchymal stem cells in the occurrence and development of AR and the possible targets of their role from the animal and cell level,providing a new method and theoretical basis for the treatment of AR.It provides new ideas and new targets for developing more effective drugs to treat AR.The animal experiment is the intervention study of h UC-MSCs on AR mice.The AR mouse model was first established.On days 0,3,7,10 and 14of the modeling,mice in the AR group were subjected to intrabitoneal injection of OVA for basic sensitization.On days 15 to 28,mice in the AR group were sensitized with OVA nasal drops every day,and the blank control group was replaced with the same amount of normal saline.The modeling effect was evaluated by symptomological scores,serum inflammatory factors and nasal mucosa HE staining during sensitization.The results showed as follows:compared with the control group,mice in AR group scratched their noses frequently,sneezed more frequently,lost hair on both sides of the nose,skin redness and swelling,and symptomatological scores were all greater than 5 points.HE staining showed cilia lodging,interruption or shedding,thickened basement membrane and inflammatory cell infiltration.Moreover,the levels of IL-4,IFN-γand Ig E in serum increased,suggesting the imbalance between Th1 and Th2 cells.The results showed that AR model was successfully established.Then,h UC-MSCs were applied to intervene AR mice,and the h UC-MSCs were resuscitated and cultured.After 2 to 3 times of passage,the cells were stable.Under the inverted microscope,the cells showed whirlpool or bundle adherent growth,and the growth was rapid.h UC-MSCs were injected into AR mouse models through caudal vein and nasal drops,once every 3 days,for a total of 3 times.At the same time,dexamethasone and budesonide suspension commonly used in clinical treatment of AR were set as positive controls.During the whole process,the mice behavioral symptoms were observed and scored.Within24 h after the end of the last intervention,blood samples were collected from the inner canthus vein of mice,the serum was separated and the expression levels of inflammatory cytokines IL-4,IFN-γand Ig E were measured.The nasal mucosa of mice was stained with HE to evaluate the intervention effect of h UC-MSCs.The results showed that after caudal vein,nasal infusion of h UC-MSCs,budesonide and dexamethasone intervention,the nasal symptoms and inflammatory infiltration of mice were alleviated,and the levels of inflammatory factors were reduced,suggesting that the above interventions were effective,and the effect of h UC-MSCs injection was better.The effect of h UC-MSCs on DCs in cell experiments.CD14~+cells were isolated from human peripheral blood and induced to differentiate to i DCs in vitro by adding rh GM-CSF and rh IL-4.On the 5th day of induction,h UC-MSCs,OVA and recombinant cytokine TNF-αwere added into different culture holes for co-culture.The cell morphology was observed by inverted microscope.The expressions of co-stimulating molecules CD80 and CD86were detected by flow cytometry,and IL-12 in culture medium was detected by ELISA.Thus,h UC-MSCs and OVA stimulated the transformation of i DCs to m DCs.DCs was harvested on the 7th day and co-cultured with CD4~+T cells.After 3 days,the expressions of IL-4 and IFN-γin the culture medium were detected by ELISA,reflecting the changes in the proliferation ability of CD4~+T cells stimulated by DCs.The results showed that OVA,as an exogenous antigen,stimulated DCs maturation by dendrite elongation,increased expression of costimulatory molecules CD80 and CD86,increased expression of cytokine IL-4,and stimulated CD4~+T cell proliferation.After co-culture of DCs and h UC-MSCs in each group,the cell protrusions were significantly shorter,the cell colonies were reduced and the growth was dispersed,and the proliferation ability of CD4~+T cells stimulated by DCs in each group was inhibited.