| Objective:1.A rat model of diabetic neuropathy was established by intraperitoneal injection of streptozotocin(STZ).The recombinant adeno-associated virus was used as a vector to transfect nerve growth factor(NGF)into myocardial tissue,and the target gene NGF was studied.The effect of changes in the expression of NGF and calcitonin gene-related peptide(CGRP)in the myocardium of diabetic neuropathy rats,and the change in the distribution density of nerve fibers.2.Using recombinant adeno-associated virus as a vector,the NGF gene was introduced into the myocardium of diabetic rats by myocardial injection,and its effect on cardiac function index during acute myocardial ischemia/reperfusion(I/R)in diabetic neuropathy rats was studied.Method:The research is carried out in the following aspects:1.Effect of NGF gene transfection on myocardial NGF and CGRP expression in rats with diabetic sensory neuropathy:28 healthy male SD rats(200-250 g)were randomly divided into 4 groups(n=7): control(Control)Group,DM surgical control(Sham)group,DM myocardial injection control(DA)group,NGF cardiac transduction(DN)group.Feeding under normal conditions lasted for 8 weeks.One week after routine feeding,One week after feeding,except for the control group,the other SD rats were fasted for 12 hours,and then streptozotocin(STZ,50 mg/kg)was intraperitoneally injected.Fasting blood glucose was measured in the tail vein 24 hours after administration,and then blood glucose > 16.7 mmol/L was measured periodically for seven consecutive days for successful modeling of diabetes.At the same time,the tail-tail latency of the rat tail was measured weekly and the relevant changes were compared.At the end of the third week,intraperitoneal injection of water and chloral aldehyde anesthesia,mechanical ventilation,myocardial point injection of NGF gene transfection.At the end of the 8th week,the expression of NGF and CGRP in the myocardium of the 4 groups was analyzed by enzyme-linked immunosorbent assay(ELISA).The expression of NGF,CGRP and the distribution density of myocardial nerve fibers were qualitatively observed by fluorescence microscopy.2.Experimental study of myocardial NGF gene transfection on cardiac function of I/R injury in diabetic rats.The experiment was divided into 4 groups: control(Control)group,DM myocardial injection group(Sham)group,DM myocardial injection control(DA)group,DM heart transduction(DN)group.Above the same feeding conditions,a total duration of 8 weeks.In addition to the Control group,other rats were injected intraperitoneally with STZ(50mg/kg)to establish diabetic rat model.At the end of the third week,intraperitoneal injection of chloral hydrate was anesthetized,and the myocardial point of the rat was injected under mechanical ventilation to transduce the NGF gene.At the end of the 8th week,the myocardium was subjected to acute I/R.The heart rate(HR),left ventricular systolic pressure(LVSP),left ventricular end-diastolic pressure(LVEDP),and maximum left ventricular pressure(+dp/dtmax)of the left ventricular pressure were recorded during the period and the maximum rate of decrease in left ventricular pressure(-dp/dtmax),comparing changes in cardiac function during acute myocardial I/R.Result:1.After 7 weeks of diabetes disease,compared with the Control group,the tail-flick latency of the rats in each group of diabetes was prolonged after 2 weeks of intraperitoneal injection of STZ,and the appendix latency was significantly prolonged from the 5th week(P<0.05).Compared with the Control group,the expression of NGF and CGRP in the Sham group and DA group was significantly decreased(P<0.05),and the distribution density of nerve fibers was decreased.Compared with the Sham group and DA group,the expression of NGF and CGRP in the DN group was significantly elevated(P < 0.05),and the density of nerve fiber distribution increased.2.The NGF gene was transduced by myocardial injection.Compared with the Control group,the other 3 groups of LVSP,HR,+dp/dtmax,-dp/dtmax decreased significantly(P<0.05),and LVEDP increased significantly(P<0.05).Compared with Sham group and DA group,LVSP,HR and LVEDP decreased significantly in DN group(P<0.05),while +dp/dtmax and-dp/dtmax had no significant difference.Conclusion:1.In rats with diabetic sensory neuropathy,the expression of endogenous NGF and CGRP in the myocardium is decreased,and the nerve fibers are decreased.The expression of NGF and CGRP in myocardial tissue was up-regulated after transfection of NGF,and the nerve fibers were partially regenerated.;2.Intramyocardial injection of AAV9-NGF gene can effectively alleviate cardiac function damage during cardiac I/R in diabetic rats and increase the defense ability of diabetic rats. |
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