大鼠烫伤早期心肌组织水通道蛋白1表达及其与心肌水肿的关系

Expression of aquaporin-I in myocardium of rats in the early stage after scald and its relationship with myocardial edema

目的了解水通道蛋白1（AQP-1）在大鼠烫伤早期心肌组织中的表达变化及其与心肌水肿的关系。方法选取36只Wistar大鼠按照随机数字表法分为证常对照组（6只，不行任何处理）、烫伤组（30只），烫伤组大鼠在麻孵后于其背部造成30％FBSAm度烫伤，伤后腹腔注射林格平衡盐溶液抗休克。于伤后2、8、12、24、48h收集烫伤组大鼠左心室心肌组织和血清标本（各时相点取6只大鼠），采用于湿质量法检测心肌组织含水率，免疫组织化学染色观察AQP-1在心肌组织中表达分布，实时定量PCR检测心肌组织AQP．1mRNA表达，ELISA法测定血清心肌肌钙蛋白I（cTnI）含量。正常对照组大鼠行相同检测。对数据进行单因素方差分析和LSD检验，分别对烫伤组大鼠伤后各时相点AQP—lmRNA表达量与相应时相点的心肌组织含水率、血清eTnI含量进行相关性分析。结果与五：常对照组大鼠比较，烫伤组大鼠伤后8～48h心肌含水率均明显增加（P值均小于0．01），其中伤后12h达峰值[（80．79±0．12）％]。免疫组织化学染色显示，AQP-1主要表达于I下常对照组和烫伤组大鼠心肌组织的毛细fIIL管内皮细胞和心肌细胞膜，其中烫伤组大鼠伤后2～48h心肌组织中AQP．1表达明显增多。与正常对照组大鼠比较，烫伤组大鼠伤后2～48h心肌组织AQP—1mRNA表达明显增加（P值均小于0．01），其中伤后12h达峰值（6．2±0．7）。与正常对照组大鼠比较，烫伤组大鼠血清cTn1含量伤后2～48h均明显增加（P值均小于0．01），其中伤后12h达峰值[（5．83±0．51）p,g／L]。烫伤组大鼠心肌组织AQP—1mRNA表达量与心肌组织含水率、血清cTnI含量均呈显著正相关（r值分别为0．849、0．973，P值均小于0．01）。结论大鼠烫伤后AQP-1可能参与心肌组织水肿的形成。

Objective To investigate the changes in aquaporin-1 （ AQP-1 ） expression in myocardi- um of scalded rats in early stage of a burn injury, and to analyze its relationship with myocardial edema. Methods Thirty-six healthy Wistar rats were divided into normal control （ l = 6, without scald） and scald （ n = 30） groups according to the random number table. Rats in scald group were inflicted with 30% TBSA full-thickness scald on the back, and intraperitoneally injected with Ringerrs solution fur antishock treatmerit. Myocardium tissue from left ventricle and serum specimen in rats of seald groupwere collected at post scald hours （PSH） 2, 8, 12, 24, and 48 （with 6 rats at each time point）. Myocardial water ratio was de- termined by dry-wet weight method. The distribution of AQP-I protein in myocardium was observed with immunohistochemical staining. The expression of myocardial AQP-I mRNA was assessed with quantitative realtime PCR. The serum content of cardiac troponin-1 （cTnl） was determined with ELISA. The rats in normal control group were detected with above-mentioned method. Data were processed with one way analysis of variance and LSD test. Correlation analysis was performed between AQP-I mRNA and myocardial water ratio, AQP-I mRNA and the serum content of cTnI in scald group at each time point. Results Compared with that in normal control group, the myocardial water ratio in scald group was markedly increased during PSH 8-48 （ Pvalues all below0.01）, and it peaked at PSH 12 [（80.79±0.12）%]. In both groups, AQP-Iwas mainly expressed in endothelial cells of capillaries and pericellular membrane of myocardial cells. The expression of AQP-1 in scald group was markedly increased from PSH 2 to PSH 48. The expression of myocardial AQP-1 mRNA in scald group was markedly higher from PSH 2 to PSH 48 than that in normal control group （ Pvalues all below0.01）, and it peaked at PSH 12 [（6.2±0.7）%]. The serum content ofcTnI in scald group was obviously higher from PSH 2 to PSH 48 than that in normal control group （ P values all below 0.01 ） , and it peaked at PSH 12 [ （ 5.83 ± 0.51 ） μg/L]. There were statistically positive correlations between AQP-1 mRNA expression and myocardial water ratio （ r = 0. 849, P 〈 0.01 ） , AQP-I mRNA expression and the serum content of cTnI （ r = 0. 973, P 〈 0.01 ） in scald group. Conclusions AQP-1 may play a key role in the development of myocardial edema in rats with scald.