| Objectives:In this experiment,based on screening and obtaining a model of natural aging macaques,the heart of natural aging macaques is studied,and the possible mechanisms involved.Methods:Rhesus monkeys with an average age of 24 years old were used as the natural aging macaque model and named as the Elderly group.Healthy Rhesus monkeys with an average age of 7 years were used as the young control group(Young-adult group),each with three animals.They were purchased from the Kunming Zoological Institute of the Chinese Academy of Sciences.Echocardiography was performed;the weight of the rhesus monkey was routinely weighed,the heart tissue of the rhesus monkey was exposed and excised,the rhesus monkey was killed,the heart weight was weighed,and the heart weight ratio was calculated;the Hematoxylin-eosin staining method Observe the gross section,inflammatory cell infiltration,myocardial cell necrosis and hypertrophy of each group of cynomolgus monkeys;Masson staining method to observe the degree of myocardial fibrosis;fluorescent Tunel staining technique to detect the degree of myocardial cell apoptosis;ELISA method to detect myocardial fibrosis Expression levels of related factor III procollagen peptide and type I procollagen peptide;qPCR and Western blot techniques were used to detect messenger RNA(mRNA)and protein expression levels of nuclear factor-related factor-2(Nrf2),heme oxygenase-1(Ho-1)and quinone oxidoreductase 1(NQO1)in myocardial tissue.Results:1.Compared with the Young-adult group of macaques,the Elderly group of macaques has decreased mobility,fur shedding,and gray hair.A small amount of hair color turns white,and drinking water intake is reduced;2.Compared with the Young-adult group,the Elderly group's body weight and heart wet weight increased significantly(P<0.05),but there was no significant difference between the two groups' heart weight ratio(P>0.05);3.Compared with the Young-adult group,the Elderly group increased the LAD,LVDD,LVPWT,and I VST,but there was no significant difference(all P>0.05).However,the E/A ratio of rhesus monkeys in the Elderly group decreased significantly(P<0.05),and the values of EF and FS decreased,but did not reach statistical significance(all P>0.05);4.Changes in cardiology:HE staining results suggest that compared with the Young-adult group of macaques,the Elderly group of macaques showed a widening of the myocardial space,thickening,and disorder of myocardial fibers;Masson staining results suggest that it is similar to the Young-adult group of macaques.Compared with the Elderly group,the myocardial fibrosis of the macaque monkey increased;Tunel staining results showed that compared with the Young-adult group,the Elderly group had no significant difference in myocardial apoptosis rate(P>0.05);5.ELISA test results showed that:compared with the Young-adult group of macaques,the Elderly group of macaques type III and type I procollagen peptide content increased,but did not reach statistical differences(all P>0.05);6.The results of qPCR and Western blot indicated that there were Nrf2,Ho-1,and NQO1 mRNA and protein expressions in the myocardial tissues of the two groups of macaques,and the expression levels of the myocardial tissues in the macaques of the Elderly group were significantly lower than those of the Young-adult group(P<0.05).Conclusions:1.The natural aging process can cause myocardial gap widening,myocardial fiber thickening,disordered arrangement,collagen deposition,and other changes;ELISA detection found increased collagen content in myocardial tissue;echocardiographic detection found diastolic function decreased.It is suggested that the early stage of heart aging in rhesus monkeys may be due to myocardial fibrosis and diastolic dysfunction.2.Changes in heart structure related to aging increased myocardial collagen content and impaired diastolic function may be related to decreased expression of Nrf2,Ho-1,and NQO1.Oxidative stress pathways may be involved in the aging process of the rhesus monkey heart.Objectives:To study the effect of bone marrow mesenchymal stem cells transplantation on the heart of aging rhesus monkeys.Methods:Bone marrow mesenchymal stem cells(BMMSC)were cultured in vitro by in vitro amplification method.BMMSC were identified by observing the cell morphology and cell surface antigens of BMMSC and induced BMMSC to differentiate into bone,fat,and chondrocytes.Multiple differentiation potentials to obtain fourth-generation of BMMSC;5 of 9 natural aging macaques were randomly selected as BMMSC treatment group and 4 as aging group.Five 7-year-old macaques were selected as the young control group(Young-adult group).After 180 days of BMMSC transplantation,echocardiography was performed;the weight of the rhesus monkey was routinely weighed,the heart tissue of the rhesus monkey was exposed and excised,the rhesus monkey was killed,the heart weight was weighed,and the heart weight ratio was calculated;the Hematoxylin-eosin staining method Observe the gross section,inflammatory cell infiltration,myocardial cell necrosis and hypertrophy of each group of cynomolgus monkeys;Masson staining method to observe the degree of myocardial fibrosis;fluorescent Tunel staining technique to detect the degree of myocardial cell apoptosis;ELISA method to detect myocardial fibrosis Expression levels of related factor III procollagen peptide and type I procollagen peptide;qPCR and Western blot techniques were used to detect messenger RNA(mRNA)and protein expression levels of nuclear factor-related factor-2(Nrf2),heme oxygenase-1(Ho-1)and quinone oxidoreductase 1(NQO1)in myocardial tissue.Results:1.Results of cell culture,identification,and differentiation induction:BMMSC were cultured with adherent tissues,which showed that BMMSC were large in size and vigorously grown,with long spindles and polygons;the fourth-generation BMMSC expressed CD29,a positive marker of mesenchymal stem cells.CD90 and CD105,do not express the negative markers of mesenchymal stem cells CD34 and CD45,and the fourth-generation BMMSC have osteogenic,adipogenic,and chondrogenic differentiation-inducing potential,which is consistent with the characteristics of BMMSC2.Before and after BMMSC transplantation treatment in Elderly group of rhesus monkeys,hair color became lighter after 180 days of BMMSC transplantation treatment,and the number of hairs in gray and white areas was thinner than before treatment;3.After being treated with BMMSC in the Elderly group of macaques,body weight,heart wet weight,and heart weight ratio changed,but no significant difference was found(all P>0.05).Compared with the Young-adult control group,the Elderly group and Elderly-treatment group had significantly increased body weight and heart wet weight(all P>0.05);4.The Elderly group of macaques improved in LAD,LVDD,LVPWT,and I VST after treatment with BMMSC,but there was no significant difference,and there was no significant difference compared with the Young-adult control group of macaques(all P>0.05);treatment with BMMSC Afterwards,the E/A ratio of rhesus monkeys in the Elderly group improved,but there was no significant difference(P>0.05),EF and FS increased,but there was no significant change(P>0.05),compared with the young-adult control group The E/A ratio of rhesus monkeys in the Elderly group and Elderly-treatment group was significantly reduced(P<0.05);5.Cardiology results showed that after treatment with BMMSC,the Elderly group of macaques showed no significant changes in inflammatory infiltration of myocardial cells,hemorrhagic foci,cell necrosis,myocardial fibrosis,and myocardial cell apoptosis rate.Compared with the rhesus monkeys in the group,the Elderly group and the Elderly-treatment group showed changes in the widening of myocardial space,thickening of myocardial fibers,disordered arrangement and increased fibrosis,but there was no significant change in the degree of cardiomyocyte apoptosis6.ELISA test results showed that after treatment with BMMSC in Elderly group,type? and type ? procollagen.Peptide content decreased,but there was no significant difference(P>0.05),and there was no significant change compared with the young-adult control group monkey(P>0.05);7.The results of qPCR and Western blot showed that after treatment with BMMSC in Elderly group,the mRNA and protein expressions of Nrf2,Ho-1 and NQO1 in myocardial tissue were significantly increased(all P<0.05),but did not reach Young-adult The level of the control group(all P<0.05).Conclusions:BMMSC transplantation can activate the nrf2-are anti-oxidative stress pathway,significantly improve the expression of Nrf2,ho-1 and NQO1 in the aging myocardial tissue,significantly improve the oxidative stress state of the aging heart,delay the changes in the structure and function of the heart. |
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