| Cardiovascular disease is one of the life-threatening diseases in the world.Myocardial cells become necrosis and are replaced by collagen tissue because of myocardial ischemia or hypoxia.Myocardial cells are damaged,which leads to declining cardiac function,ventricular remodeling,heart failure or myocardial infarction.The common treatment ways are drug therapy,thrombolysis therapy and surgical treatment.These ways can reduce the ventricular remodeling and protect the rest of the myocardial cells,but can not repair the damaged parts of the organization and increase myocardial cells.At present,researchers find some induced factors which can induce the myocardial cells restore the proliferation capacity and regenerate cardiac tissue.Our research group developed a type of recombinant protein IGF1-24.In the early stage of this experiment,we found that the recombinant protein IGF1-24 could significantly promote the proliferation of H9C2 myocardial cells.And we indicated that it might has repair effect on myocardial injury.Therefore,we planned to further confirm whether IGF1-24 had the potential of repair function in myocardial injury of SD rats,which could provide a pharmacy basis for it.We investigated the following aspects in this paper: firstly,constructed the expression vector of PET-32a-IGF1-24,induced,purified and verified the IGF1-24 protein.Secondly,we injected excess isoproterenol into rats which led to the myocardial injury.According to the concentration of cardiac troponin T in serum and histopathological section,we confirmed the success of the model.Thirdly,the recombinant protein IGF1-24 was injected into myocardial damaged rats and detected the effect of the recombinant protein.Finally,the functional pathway of the recombinant protein IGF1-24 was preliminarily studied.Experimental contents and results of this paper are as follows:(1)We constructed PET-32a-IGF1-24 plasmid.And induced expression of recombinant protein IGF1-24,when the temperature is 16 ?,IPTG concentration is 0.6 mM and time is 6 h.The bacterial liquid which was crushed by ultrasonic purified by Ni Agarose column.The recombinational protein IGF1-24 was prepared by separating and purifying.After tested by Western blot,the recombinant protein IGF1-24 was determined.And the concentration of the recombinant protein IGF1-24 was 0.2mg/mL,which was measured by the BCA protein concentration detection kit.(2)SD rats were intraperitoneally injected with isoproterenol at a concentration of 80mg/kg for 7 consecutive days.We observed the changes of physiological signs on rats.After calculating the growth of body weight,it was found that the weight gain of rats was obviously slow.And the concentration of cardiac troponin T in serum was significantly increased which measured by Elisa kit.The HE staining showed that the heart tissue of rats was damaged and the myocardial cells were destroyed.Thus,the myocardial injury model was successfully constructed.(3)The recombinant protein IGF1-24 was injected into the tail vein of rats at 100?g/kg for 7 consecutive days.After treatment with recombinant protein IGF1-24,growth of body weight on treatment rats added and the concentration of cardiac troponin T in serum decreased.The HE staining showed that the damage of cardiac tissue was alleviated.The experimental results confirmed that the recombinant protein IGF1-24 had a repair effect on myocardial injury.(4)Why the recombinant protein IGF1-24 was able to treat myocardial damage was preliminary explored in this paper.Using EDU cell proliferation assay kit,we found that IGF1-24 could induce cardiomyocyte regain proliferation ability which made up for the loss of myocardium.By TUNEL staining and immunofluorescence,it was found that IGF1-24 could reduce the apoptosis of myocardial tissue cells and the secretion of inflammatory cytokines IL-6 and TNF-?.This experiment studied the recombinant protein IGF1-24 in the role of myocardial injury repair.Results showed that it could repair the impaired myocardial tissue.The possible mechanisms were that it induced myocardial cell proliferation,reduced apoptosis and the inflammation factor.This study will provide research foundation for the recombinant protein IGF1-24 as a drug. |
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