On Study The Variation Of Autonomic Nerve Remolding Of And Medicine Intervention Influencing On It In Rapid Pacing Rabbit

Objective:1) To explore the expression of nerve growth factor (NGF) and its effect on neural remodeling after rapid right atrial pacing in rabbits.2) Spectral analysis of HRV included determination of total power spectral density (mesc2),integral powers of spectrum densities for high frequency (mesc2) taken for the marker of mainly vagal activity,forlow frequencies (mesc2) taken for the marker of mainly sympathetic activity.Methods:1) The rapid right atrial pacing rabbits were classifed into 3 groups (4hours,12 hours,24 hours after rapid right atrial pacing). By immunohistochemistric method,the Expression of NGF protein and sympathetic innervation and vagus nerve were examined in right atrium (RA),and left atrium (LA),in different stages and groups.2) The rabbits were connected to the ECG machine by three ECG leads;two leads on the upper chest and one lead on the back of the neck. The HRV data were collected and this protocol was consistent with all rabbits. Meanwhile, to investagate the direct effects of atorvastatin on HRV,and learn the mechanism of the effects of atorvastatin on HRV. Results:1) The protein of NGF was detected in the cytoplasma of non-pacing. In 4h group,the expressions of NGF protein were significantly higher in RA, LA than those in control areas (P<0.05),the density of sympathetic nerve were increased in RA,LA signifieantly,and NGF protein expression correlated with sympathetic innervation in RA,LA (P<0.05). In12h group,the Expression of NGF protein and density of sympathetic nerves in RA,LA were significantly increased (P＜0.05),NGF protein expression correlated with sympthetic innervation in RA,LA (P<0.05). In 24h group,the expressions of NGF protein increased than those in control rabbits (P<0.05),the density of sympathetic nerve was higher than that in 4 and 12 h groups and the extent of innervation was enlarged in each area.2) Time-domain HRV parameters was a significant increase during AF in rapid pacing rabbits. Statistically significant increases in spectral power at 0.15Hzwere observed when compared with control groop. HRV in RAP rabbits treated with 2 mg·kg-1day-1 atorvastatin was not statistically different from that in normal contrals. Conclusion:1) The expression of NGF protein in myocardium was dynamic and Correlated with sympathetic reinnervation and hyperinnervation,which indicated that NGF might play a nerve-nutritious role and take part in the post- paced neural remodeling and neuroendocrine regulation.2) The novel findings of this study are that HRV is partly reversed toward normal by atorvastatin in RAP rabbits model and,second, that LF, HF, HR are increased uniformly, in addition to data presented previously,these data support the concept of statin effects on the autonomic nervous system as part of their pleiotropic efficacy.