心房快速起搏和链霉素对兔心房电重构和心房钠尿肽影响的研究

Effects of rapid atrial pacing and streptomycin on atrial electrical remodeling and atrial natriuretic peptide in rabbits

目的探讨心房快速起搏(RAP)和牵张激活性离子通道(SAC)阻断剂链霉素对兔心房电重构和心房钠尿肽(atrial natriuretic peptide,ANP)的影响。方法选用新西兰白兔18只,随机分为RAP组和RAP+链霉素组[起搏前静脉推注链霉素30 mg/kg,然后以25μg/(kg·h)维持静脉滴注],每组9只。检测2组心房有效不应期(AERP),采用ELISA法测定起搏前和起搏后15 min、30 min和1 h血浆ANP水平及环磷酸鸟苷(cGMP)浓度。结果与基线比较,RAP组起搏后1 h的AERP200和AERP150明显缩短(P<0.05),RAP+链霉素组起搏后15 min的AERP200和AERP150明显延长(P<0.05)。与RAP组比较,RAP+链霉素组在起搏后30 min和1 h的AERP200和AERP150明显延长,差异有统计学意义(P<0.05,P<0.01)。RAP组AERP频率适应性与RAP时间呈负相关(r=-0.287,P<0.05)。RAP组房颤诱发率明显高于RAP+链霉素组,差异有统计学意义(33%vs 0,P<0.05)。与基线比较,随着起搏时间延长,RAP组15 min、30 min、1 h ANP、cGMP浓度明显增加(P<0.05)。与RAP组比较,RAP+链霉素组在起搏后15 min ANP、cGMP浓度有所降低(P>0.05),起搏后30 min和1 h ANP[(97.4±9.5)pg/ml vs(174.1±16.8)pg/ml,P=0.039;(81.3±9.6)pg/ml vs(263.2±34.6)pg/ml,P=0.001]、cGMP[(1.1±0.2)pmol/ml vs(2.2±0.3)pmol/ml,P=0.029;(1.0±0.1)pmol/ml vs(2.4±0.2)pmol/ml,P=0.004]明显降低。结论SAC阻断剂链霉素能显著抑制心房急性电重构,抑制RAP引起的血浆ANP及cGMP浓度的增加。

Objective To investigate the effects of rapid atrial pacing(RAP)and stretch-activated channels blocker,streptomycin,on atrial electrical remodeling and atrial natriuretic peptide(ANP)in rabbits.Methods Eighteen New Zealand white rabbits were randomly and equally divided into RAP group and RAP+streptomycin group[intravenous injection of 30 mg/kg streptomycin before pacing,and then maintained intravenous drip infusion at 25μg/(kg·h)].Atrial effective refractory period(AERP)was detected in the two groups.Plasma levels of ANP and cyclic guanosine monophosphate(cGMP)were measured by ELISA at 15 and 30 min and 1 h after pacing.Results Compared with the baseline,AERP_(200)and AERP_(150)were significantly shortened at 1 h after pacing in the RAP group(P<0.05),and were obviously longer at 15 min after pacing in the RAP+streptomycin group(P<0.05).The two indicators were notably longer in the RAP+streptomycin group than the RAP group at 30 min and 1 h after pacing(P<0.05,P<0.01).AERP frequency adaptation was negatively correlated with RAP time in the RAP group(r=-0.287,P<0.05).The incidence of atrial fibrillation was significantly higher in the RAP group than the RAP+streptomycin group(33%vs 0,P<0.05).With the prolongation of pacing time,the ANP and cGMP levels were increased gradually in the RAP group at 15 and 30 min and 1 h after pacing(P<0.05).Compared with the RAP group,the ANP and cGMP levels were declined in the RAP+streptomycin group at 15 min after pacing(P<0.05),and the ANP level at 30 min and 1 h after pacing(97.4±9.5 pg/ml vs 174.1±16.8 pg/ml,P=0.039;81.3±9.6 pg/ml vs 263.2±34.6 pg/ml,P=0.001),and that of cGMP at the same time points(1.1±0.2 pmol/ml vs 2.2±0.3 pmol/ml,P=0.029;1.0±0.1 pmol/ml vs 2.4±0.2 pmol/ml,P=0.004)were decreased significantly.Conclusion Stretch-activated channels blocker,streptomycin,can significantly inhi-bit acute atrial electrical remodeling and suppress the increased ANP and cGMP levels caused by RAP.