兔室颤心搏骤停模型的建立

Ventricular fibrillation-induced cardiac arrest model in rabbits

目的建立一种简单、方便、有效的兔心肺脑复苏（CPCR）模型。方法采用体表交流电诱发室颤的方法制作兔心跳骤停（CA）模型，依据CA时间的长短，27只新西兰大白兔随机分为CA 8min、CA 5min和CA 3min组，每组9只，随后进行胸外心肺复苏术（CPR）。自主循环恢复（ROSC）后4h检测血肌钙蛋白Ⅰ水平，72h后处死动物，取海马组织尼氏染色和TUNEL法凋亡细胞检测，计算每40×倍视野下海马CAI区尼氏染色阳性细胞数和凋亡细胞数。另取2只兔作为对照组，只进行外科操作不进行致颤和CPR。各组数据依据正态检验结果用单因素方差分析（one-way ANOVA）或秩和检验（Mann-Whitney rank），多重比较用LSD—t检验，ROSC率的比较用行×列连表χ^2检验，两样本均数的比较用t检验，P〈0．05表示差异具有统计学意义。结果CA8 min，CA5 min和CA3min组各有4，5，7只动物ROSC，各组间ROSC率差异无统计学意义。ROSC后各组动物的存活时间分别为（1．67±2．55）h，（37．78±30．27）h，（12．0±14．97）h，CA3min组和其他两组之间差异具有统计学意义（P〈0．05）。ROSC后4h三组之间血浆肌钙蛋白水平分别为（0．71±0．07）ng／mL，（0．55±0．08）ng／mL，（0．45±0．06）ng／mL，CA3min组和其他两组之间差异具有统计学意义（P〈0．05）。与对照组相比，ROSC后72h海马CAI区出现了神经元细胞的缺失和凋亡，CA3min组和对照组尼氏染色阳性细胞数分别为（34．33±6．19），（55．75±5．91）（P〈0．01），对照组中海马CAI区未见有凋亡细胞。结论兔CA3min后进行CPR有较长的存活时间，ROSC后72h海马CAI区可见神经元细胞缺失和凋亡，因此该模型可能是一个比较理想的CPCR研究模型。

Objective To establish a simple, easily-producible and practical cardiopulmonary cerebral resuscitation model in rabbits. Method Cardiac ventricular fibrillation was induced in 27 New Zealand rabbits by alternating electric current. The rabbits were randomly divided into three groups according to the duration of untreated cardiac arrest （CA） ：CA-8 min group （ n = 9）, CA-5 min group （ n = 9） and CA-3 min group （ n = 9）. All animals received cardiopalmonary resucitation （CPR） until retum of spontaneous circulation （ROSC）. The sample of vein blood was collected for the measurement troponin Ⅰ level at 4 hours after ROSC. The animals were sacrificed at 72 hours after ROSC, hippocampus were removed and fixed in 3% formalin, and coronal sections were analyzed by TUNEL staining and NISSLE staining. The other two animals without ventricular fibrillation or CPR served as sham-operated group. One-way ANOVA or Mann-Whitney rank was used to determine the statistical significance among the three groups. R × C test was used for ROSC, LSD test for multiple comparisons, and t test for comparisons of means between two independent samples. A two-tailed value of P 〈 0.05 was considered statistically significant. Results There were no differences in rate of ROSC among groups. No animals survived until72 hours after ROSC in CA-8 min group and CA-5 min group, while three animals in CA-3 rain group survived. In group CA-8 min, CA-5 min and CA-3 min, the survival time of animals after ROSC were （1.67 ± 2.55） h, （37.78 ± 30.27） h, （12.0 ± 14.97） h, respectively. There were significant differences in the survival time of animals after ROSC and troponin Ⅰ level after ROSC 4 h between CA-3 min group and the other two groups （P 〈 0.05）. Compared with animals in CA-3 min group, sham-operated animals （ n = 2） did not have neuronal degeneration or TUNEL positive cells in the bippocampus CAI area. Conclusions CPR initiated as soon as 3 min after CA can give longer survival tome to the rabbits. The rabbits have neuronal degeneration and apoptosis in the hippocampus CAI area at 72 hours after ROSC. It may be an ideal animal model for investigation on CPCR.