Changes And Effects Of T Lymphocyte In Subacute Aging Mouse Induced By D-Galactose

Aging is the inevitable phase of body`s growth,which involved in the degradationof the functions of multiple organs and systems.At present,there is no unifiedunderstanding on the mechanism of aging,and are several hypotheses.At nineteensixties,Wolford firstly postulated the immunological theory of aging,which holds thatthe immune system fundamentally involved in the body’s aging process.Aging also havean important impact on the immune system,on the one hand it will reduce the defenceability,and increase the risk of infection,on the other hand it could result in autoimmunereactions,and even autoimmune disease,thus speeding up the aging process.As the important central immune organ,thymus is the place where T cell is todevelop and mature.The changes of structure and function in thymus of the aging havean important influence on the development and mature of T cell.Stimulated by theantigen in the periphery,T cell can differentiate into different subsets, and play differentrole in the body. Aging can influence the signal transduction of T cell and inhibit theactivation of different T cell subsets,so affect the immune function of the wholebody.Spleen is an important immune organ in the periphery,and is the main place whereperiphery T cell settled down,which plays an important role in the immune defence andreponse.The changes of spleen T cell subsets produce important influence on thefunction of the immune system.In this study,we established subacute aging mouse model by100g/L D-galactose,and make a primary discussion and analysis on the changes of T cell in thymus andspleen,which could afford some experimental information for the further study about therelatationship between immune system and aging.PartⅠ Establishment and identification of subacute aging mousemodel induced by D-galatoseObjective:To establish and identificate the subacute aging mouse model inducedby D-galatose. Methods:Female Kunming mice of8weeks old were injected with D-galactose of12.5mL/(kg·d) by subcutaneous in scruff for42days.The animals’ living conditions andbiological behaviors were observed everyday.SOD activities and MDA content of serumwere measured to determine whether the aging model was successfully established.Result:During the42days, gradually, the model mice showed bending body,looseskin,slow action and so on.The activities of SOD in the serum were significantlydecreased(P<0.01),and the content of MDA in the serum was significantlyincreased(P<0.01).Conclusion:The D-galactose subacute aging mouse model was successfullyestablished.PartⅡ Changes and effects of thymus T cell in aging mouseinduced by D-galactoseObjective:To explore the changes and effects of thymus T cell in aging mouseinduced by D-galatose.Methods:On the basis of successfully establishing aging mouse model,detect thesignificant membrane molecules of thymic T cell by Immunofluorescence technique andFlow Cytometer.The Fas expression of thymocytes was observed byImmunohistochemistry method,and the changes of the structure of thymus was observedby H-E staining methods.Results:In model mouse, the CD3molecule in the thymocytes wasdecreased(P<0.01).The thymus naive T cell significant molecule,CD45RA wasdecreased(P<0.05).T cell activation-related molecules,CD28and CD25were bothdecreased(P<0.05),and PD-1was significatnly inereased(P<0.01).The memory T cellsignificant molecule,CD196was inereased,but was not significantly compared to thecontrol mice.Fas in the thymocytes was increased(P<0.05).H-E thymic section indicatedthat the area of cortex was decreased,and the boundary between cortex and medullabecame unclear,and the Thymic cells became sparse.Conclusion:The totle T cells in the thymus of the ageing was decreased, and inwhich, naive and active T cell were decreased and memory T cell was increased Thethymic structure and functions were decreased in aging. PartⅢ Changes and effects of spleen T cell in aging mouseinduced by D-galactoseObjective:To explore the changes and efforts of spleen T cell in aging mouseinduced by D-galactose.Methods:On the basis of successfully establishing aging mouse model, spleen Tcell subsets were detected by Immunofluorescence technique and Flow Cytometer.TheFas expression of spleen cells was observed by Immunohistochemistry method,and thechanges of the structure of spleen were observed by H-E staining methods.The contentof IFN-γ and IL-4in serum were measured by ELISA.Result:The naive T cell significant molecule, CD45RA was decreased(P<0.05).Tcell activation-related molecule, CD25was decreased(P<0.05).The Foxp3inCD4+CD25+T cell was increased(P<0.01).Fas in the spleen cells was increased(P<0.05).H-E spleen section indicated that the area of white pulp was decreased, but red pulp wasincreased.The boundary between white pulp and red pulp became unclear.The spleencells became sparse and the marginal zone became deformation.The content of IFN-γand IL-4in the serum were decreased of model group (P<0.01).Conclusion:In spleen of the aging, the percentage of naive and active T cell weredecreased,but the percentage of CD4+CD25+Tr subset was increased.The spleen cellsapoptosis was increased, and structure and functions of spleen were decreased in theaging.