Experimental Study On Myonuclei Replacement And Resistance Training In Aged Rats

Along with the development of science and technology and social economy, people’smedical condition and living standards have been improved significantly, hence, the averagehuman lifespan has been greatly improved. After the execution of the family planning in1980s, birth rate of the newborn baby had gone down sharply, which makes the proportion ofyoung people today declined to the nation’s population. The proportion of the aged populationincreases, which makes our country aged before becoming developed. The Aged societyshould have a huge amount of influence over the development of the society in the future.Action ability drops. Dropped action ability leads to reduced muscle and less motion, whichwould cause increasing of high blood fat, high blood pressure, therosclerosis, and theincidence of disease of heart head blood-vessel. Muscle power would be further weakened,then, make the old people’s action inconvenient, even increase falling risks. Therefore,improving muscle strength becomes the core element to ameliorate the aged person’s life.Through the way of resistance exercise, muscle of the old are strengthened, which makes theactivity scope broadened and the activity level improved, and reduces the fat in the blood ofthe content, reduces or avoids a variety of diseases. Muscle power and weight peak in the ageof twenty to thirty, and then gradually declined. With aging, muscle power and weight show adownward trend. Muscle loss in this period is the general performance. Resistance trainingcan slow up muscle loss, but what has been the hot search spot is how to get a more secureand effective method between training load and training repeat in resistance training, andwhat leads researchers penetrate is the mechanism research on resistance training slowing upmuscle loss. Skeletal muscle is multinucleated cells. The relevant studies on the meaning ofmyonuclei existence, the function of myonuclei and the correlation between resistanceexercise and muscle aging and myonuclei are not comprehensive. The amount and function ofthe multinucleated cells is the research content, aged individual research object. Nucleus weremarked in the experimental process, going against the health of human body, therefore,14months old rats were selected as the research object.60rats were randomly grouped into quietgroup, light-load group, medium-load group and heavy-load group,10only in each group.Fresh myonuclei of skeletal muscle would be marked with5-bromo-2-deoxyuridine andidentified with immunohistochemistry. Meanwhile, in skeletal muscle, normal and apoptotic nucleus would be discriminated by hochest33258, then research on the changes taken place inusing of resistance exercises on fresh myonuclei and apoptotic myonuclei.The experiment is divided into three parts:Part one: Through the experiment, the purpose is to look for myonuclei in skeletalmuscle and to discuss the resources. The research object is the male SD rats. With brdu asmarkers of myonuclei in skeletal muscle, new nuclei in skeletal muscle will be showedthrough the immunohistochemical method, And further use of newborn muscle immuneelectron microscope (tem) would confirm the existence of the nuclei. Result shows theexisting new nuclei in skeletal muscle in figure5, figure6, figure8and the source ofmyonuclei in skeletal muscle is discussed.Part two: Research purpose is through the experimental method to find out the evidenceof co-existence of new myonuclei and apoptosis in skeletal muscle fibers. The experimentobject are the male SD rats. Research methods is through longitudinal cutting in skeletalmuscle, with brdu and hechest33258marking myonuclei and apoptosis in skeletal muscle, andimmunofluorescence used to display. With the figure9to figure11,the result shows thatmyonuclei and apoptosis in skeletal muscle co-exist in the skeletal muscle fibers, whichprovides the evidence for " myonuclei replacement" phenomenon.Part three:The research is to attempt to study the influence on "myonuclei replacement"in aging skeletal muscle with different load of resistance training. The experiment object are4018-months-old male SD rats Randomly divided into quiet group, the large, medium, smallweight training groups,10only in each group, which were trained with resistance training.The results of the study show that resistance training led to a series of changes in skeletalmuscle of aged rats. In large-load training group, the total amount of protein is0.539±0.015g/L，quiet group,0.442±0.027g/L，which shows the increasing of the total amount of proteinin skeletal muscle with resistance training. The expression of subtypes of mRNA in myosin ofmuscle fiber changed. MHCIIb in quiet group is1.023±0.013;medium-load group,0.655±0.009. MHCI in quiet group is1.21±0.018; medium-load group,1.539±0.045,which showsgreat difference between them. At the same time, the average density of myonuclei in crosscut intrinsic muscle also has corresponding change, which justifies the increasing in myonucleiwith resistance training.The research illustrates that resistance training can make number of myonuclei increased,also make the protein expression changed and total protein increased. they three have certaininternal relations. It can be deduced that new born myonuclei is important link to muscle cellsmetabolism, to existence of all three. Through the above three parts, it can be proved thatresistance training results the change in quantity of cell nucleus in skeletal muscle, meanwhile,in protein expression and in the total amount protein.This research used experimental method and viewed from " myonuclei " as basic point ofcells metabolism.The paper put forward the idea of "nuclear" metabolism, which not only canbe used to further explain the cause of skeletal muscle hypertrophy under resistance trainingand can also provide a reference for muscle disease treatment.