ABSTRACT
Objective To observe the effect of adenovirus- receptor activity modifying protein-1 (RAMP1) on nuclear factor(NF κB) and myocardial fibrosis in heart of rabbit with myocardial infarction. Methods Myocardial infarction (MI) models were developed in 54 rabbits and they were randomly divided into RAMP1 group,EGFP group and control group according to whether pAd2-EGFP-RAMP1,pAd2-EGFP or PBS was injected into infarction region and its border.At 7 d,14 d and 28 d after injection,Left ventricular function indices such as LVEF,LVSd,LVDd and LVFS were estimated by echocardiogram,the expression of NF-κB in myocardium was detected by Western blot,the plasma level of TNF-α was measured by ELISA,and fibrosis and collagen content was measured by Masson stain. Results At 7 d after adenovirus injection,the expression of RAMP1was significantly increased in RAMP1 group (67.33 ± 3.97)％ as compared to EGFP group(20.59 ±3.26) ％ and PBS group ( 23.80 ± 5.08) ％ ( P ＜ 0.05 ).The expression of NF κB was decreased in RAMP1 group ( 26.54 ± 5.13 ) ％ versus EGFP group (62.60 ± 6.18) ％ and PBS group (62.95 ±5.17)％ (P＜0.05).The plasma level of TNF-α was lower in RAMP1 group than in EGFP group and in PBS group at different time[7 d:( 136.74 ± 5.42) μg/L vs.( 196.97 ± 14.17) μg/L,(203.67 ±13.90)μg/L; 14 d:( 154.51 ± 13.61 )]μg/L vs.( 112.22±6.74 )μg/L,(160.46± 14.27)μg/L ;28 d;(51.10± 5.62)μg/L vs.( 95.55 ± 9.94 )μg/L,( 98.96 ± 12.68) μg/L,all P＜ 0.05].The collagen content was reduced in RAMP1 group as compared with EGFP group and PBS group at 14 d and 28 d [14 d:(7.10±0.98)％ vs.(19.52±2.32)％,(17.91±0.96)％ ;28 d:(17.04±2.44)vs,(34.10±5.59) ％,(33.98±4.33)％,all P＜0.01].At 28 d after infarction,the infarct size was decreased in RAMP1 group (26.54 ± 5.13) ％ compared with EGFP group (32.20 ± 3.73) ％ and control group (35.58±2.65) ％ (P＜0.01),and better heart function appeared in RAMP1 group. Conclusions The high-expression of RAMP1 could decrease the collagen deposition and fibrosis in the border of infarction and improve heart function through lower expression of NF-κB and decreasing the plasma level of TNF-α.