Alteration Of Expression Of Norepinephrine Transporter,Nerve Growth Factor And Recepter TrKA In Long-term Pressure Overload Rats

Aim: to determine the expression level of norepinephrine transporter mRNA at cardiac sympathetic nerve and the myocardial expression of nerve growth factor in long-term pressure overload rats.discuss the relationship between them.Material and Method: The long-term pressure overload model was established by constricting suprarenal abdominal aorta. 40 adult male Wistar rats were randomly divided into pressure overload group(n=30) and control group(n=10). 8 weeks After operation, echocardiograph indices (IVSd,IVSs,IVIDd,IVIDs,LVPWd,EDV,ESV,EF,SV,%FS) and ventricular mass index (LVMI) were evaluated. To investigate the protein level changes of cardiac NGF, left ventricular of both groups were removed,then routine frozen sections were made and stained with immunofluorescence method.Cardiac NET mRNA were abstracted from middle cervical-stellate ganglion complex(MC-SG complex),growth associated factor mRNA,TrkA mRNA were extract from myocardium and expression levels were determined by real-time fluorescent quantitative PCR in each group.Results: Compared with control group, echocardiograph parameters of pressure overload rats were increased. IVSs,LVPWd,IVIDs,EF,%FS were increased significantly(p<0.05). The heart size become larger and diameters of left ventricle cavity of heart failure rats increased compared with control group.LVMI was increased by 33.23%.The data showed above demonstrate that the rats were at compensation stage of heart failure. Immunofluorescence analysis showed that fluorescence staining area,which represent the protein levels of NGF increased in pressure overload group (p<0.05).Real-time fluorescent quantitative PCR assessment showed that mRNA expression levels of NET,GAP43 have no changes,and the TrKA mRNA decreased significant compared with control group (p<0.05).Conclusions: The results show that the long-term cardiac overload can lead to increased NGF protein expression level in rat heart, simultaneously Decreased TrKA mRNA level,The mRNA expression level of NET and GAP43 have no changes.Quibus we guess that the abnormality of post-transcription possibly lead to the disfunction of NET;The increased NGF protein can't make effect to the nerve growth,lower expression level of TrKA play a important role in nerve growth.