| Objective: To investigate the effect of recombinant human granulocyte colony stimulating factor combined with glucagon like peptide-1 on ischemic injury in myocardial infarction model rats.Methods: A total of 50 adult male SD rats were selected,and their body weight was 250-300 g.The model of myocardial infarction was established by ligating proximal part of the left anterior descending coronary artery.They were randomly divided into five groups: SHAM group(n=10),MI group(n=10),rhG-CSF group(n=10),LI group(n=10)and RH-LI group(n=10).Animal echocardiography in diagnosis and on avaluation of heart function was taken before and 6 weeks after surgery,including left ventricular end diastolic diameter(LVEDD),left ventricular ejection fraction(LVEF)and left ventricular fractional shortening(FS);6 weeks later all rats were killed after deep anesthesia,the Iraqi Red Pigment(HE)staining was used to observe the arrangement and fibrosis of myocardial cell.To observe the situation of myocardial fibrosis of rats and myocardial collagen volume fraction(CVF)by Masson staining;immunohistochemical staining was used to detect the expression and distribution of Connexin43(Cx43)which is the gap among the myocardium cells with the method of semi quantitative analysis by software.Results:(1)Echocardiography: compared with SHAM group,LVEDD of MI and the interventional group increased,LVEF and FS decreased significantly(P < 0.05).Compared with MI group,LVEDD of RH-LI group and LI group decreased,LVEF and FS increased significantly(P < 0.05);The RH group compared with MI group,LVEF and FS increased,the difference was statistically significant(P < 0.05),and LVEDD decreased,but the difference was not statistically significant(P > 0.05).In the intervention groups,RH-LI group LVEDD decreased,LVEF and FS increased compared with LI group and RH group significantly(P < 0.05);Compared with LI group and RH group decreased LVEDD,LVEF and FS increased,but the difference was not statistically significant(P > 0.05).(2)The results of HE staining: In SHAM group and RH-LI group,the myocardial fibers arranged regularly,clear,no obvious fibrosis;LI group myocardial fibers still rules in order,a few broken dissolved carcoplasm fibers,muscle fibers,a small amount of fibrosis;In RH group,myocardial fibers arranged irregularly with local myocardial swelling,muscle fiber twist a small amount of pulp dissolved,fibrosis;Muscle fibers in group MI were arranged in disorder,cell gap widened,myocardial fiber swelling,distortion of sarcoplasmic dissolution,fiber breakage,fibrosis significantly.(3)Masson staining: The CVF in the RH-LI Group [(25.36 ± 5.26)%] was significantly decreased compared with MI Group [(54.16 ± 9.65)%],and the CVF in the LI group[(35.64 ± 7.71)%] and RH group[(38.28 ± 7.97)%] was also significantly decreased compared with MI Group(P < 0.05).Compared with the LI group and the RH group,the CVF in the RH-LI group was significantly lower,the difference was statistically significant(P = 0.01);The CVF in the LI group was lower than that in the RH group,but there was no statistic difference(P>0.05).(4)The results of immunohistochemistry: in SHAM group,Cx43 immunohistochemical positive granules arranged regularly,zonal distribution in the adjacent myocardial cell junction,myocardial cells arranged in neat,meticulous,complete structure and there was no degeneration and necrosis,nucleus structure clear.The myocardial cells of rats in the MI group specific stained brown small ranges,lighter staining showed that Cx43 expression decreased,and Cx43 positive granules arranged in disorder,located in ventricular myocytes or intracellular side,the fuzzy boundary of myocardial tissue injury.Compared with SHAM group,the expression of Cx43 positive granules in the MI group was significantly reduced and the arrangement was disordered.Compared with MI group,RH-LI group,LI group and RH group,the cell specific staining scope,the expression of Cx43 increased,and Cx43 positive particles were distributed on the adjacent myocardial cell junction,which is most obvious in the RH-LI group,SHAM group and its approximate structure;the immunohistochemical staining of Cx43 was semi-quantitative and showed that the expression level of Cx43 in RH-LI group increased significantly compared with MI group [(0.413 ± 0.087)vs(0.126 ± 0.017),P < 0.01].The expression level of Cx43 in LI group and RH group was significantly different from that in group MI(0.304 ± 0.076)vs(0.282 ± 0.063)vs(0.126 ± 0.017),P < 0.05].In the intervention groups,Cx43 expression level in RH-LI group increased significantly compared with the LI group and RH group [(0.413 ± 0.087)vs(0.304 ± 0.076)vs(0.282 ± 0.063)](P < 0.01);In LI group,Cx43 expression levels increased compared with that in RH group,the difference was statistically significant [(0.304 ± 0.076)vs(0.282 ± 0.063),P < 0.05].Conclusion: RhG-CSF combined with GLP-1 can effectively reduce myocardial infarct size in MI model rats,improve left ventricular function through increasing expression of Cx43 in ischemic myocardium. |
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