The Effect Of Fibrin Patch With NRG-1 In The Treatment Of Myocardial Infarction

Aim:Myocardial infarction(MI)can lead to the apoptosis and necrosis of cardiomyocytes while the cardiomyocytes of adult mammals have the proliferative capacity under specific circumstances.The fibrin patch encapsulation of neuregulin 1(NRG-1),the bioactive factor with the effect of promoting the proliferation,was prepared,and the effect of the patch on the treatment of MI was investigated.Methods:The fibrin patch was prepared by fibrinogen solution of different concentrations(10 mg/mL,20 mg/mL)with 10 U/mL thrombin solution under the action of Ca2+.The tensile modulus was measured,and the biocompatibility of the fibrin patch was evaluated by implanted into normal mice and surface culture of H9c2 cardiomyocytes,and the patch with best performance was used in the following experiments.The pore size and structure of the fibrin patch were characterized by scanning electron microscopy.The downstream signaling pathway of NRG-1 was investigated by Western Blot,and the biological performance was confirmed with CCK-8 and EdU assays from qualitative and quantitative points,respectively.The effect of NRG-1 released from the fibrin patch on promoting cardiomyocyte proliferation was investigated with CCK-8 assay.Next,the effect of the fibrin patch with NRG-1 on improving cardiac function was verified in MI model of mice.The mice were randomly divided into MI group,Sham group,Patch group and Patch+NRG-1 group.Cardiac function was assessed on Day 3,7,14 and 28 after operation by echocardiography.On Day 7 after MI,several mice were sacrificed and the hearts were harvested for tissue slices.Immunofluorescence staining of Ki67 was used to assess the proliferation of cardiomyocytes in border zone and remote zone,while TUNEL staining was used to evaluate the apoptosis of cells.On Day 28,the hearts were harvested with Masson’s Trichrome staining for tissue fibrosis and CD31 immunostaining for angiogenesis.Results:Studies on biocompatibility in vitro and vivo,showed that the fibrin patch made from 10 mg/mL and 20 mg/mL fibrinogen solutions was suitable for cell adhesion growth and use in mice.And the tensile mechanical property of the fibrin patch with 20 mg/mL fibrinogen solution was even better.The Western Blot results showed that the downstream signaling pathway of NRG-1 was activated,and CCK-8 and EdU assays indicated that NRG1 had the effect on promoting the proliferation of cardiomyocytes.According to CCK-8 assay,the NRG-1 released from the patch possessed the corresponding biological performance.For the mice MI model,the fibrin patch loaded with NRG-1 on can effectively promote cardiomyocyte proliferation,reduce cell apoptosis,induce angiogenesis,inhibit fibrosis and improve cardiac function.Conclusion:The fibrin patch,prepared with 20 mg/mL fibrinogen and 10 U/mL thrombin,possessed considerable mechanical properties and good biocompatibility.while loaded with NRG-1 on,the patch can promote cardiomyocyte proliferation,reduce cell apoptosis and induce angiogenesis.Moreover,it can improve the ejection fraction,reduce infarct size and enhance cardiac function after MI.The establishment of the system would provide a new application strategy for fibrin patch in the treatment of myocardial infarction.