ABSTRACT
Objective To observe the expression changes in apoptosis-related microRNA(miRNA) in cerebral cortex after cardiac arrest-cardiopulmonary resuscitation(CA-CPR)in rats and explore the factors that may affect the mechanism of CPR. Methods 24 clean male Sprague-Dawley(SD)rats were randomly divided into three groups,the normal control group,sham operation group and CA-CPR group(each n=8). The animal model of CA induced by asphyxia was established and CPR was performed. In the normal control group,no special management was performed. In the sham operation group,only abdominal cavity anesthesia,tracheotomy,vascular puncture and electrocardiogram(ECG)were performed without clamping the trachea and resuscitating. Normal feeding in normal control group and 24 hours after tracheotomy in sham operation group,at 24 hours after recovery of spontaneous circulation(ROSC)in CA-CPR group,cerebral cortex specimens were obtained for detection of the expression of miRNA by using real time fluorescence quantitative reverse transcription - polymerase chain reaction(RT-PCR). Flow cytometry(FCM)was used to detect the neurocyte apoptotic rate. Results Compared between normal control and sham operation groups,there were no significant differences in the expression of apoptosis-related miRNA and neurocyte apoptosis rate of cerebral cortex(both P>0.05). Compared with sham operation group,in CA-CPR group, 16 miRNA expressions were up-regulated,including Let-7c,miR-15a,miR-21,miR-24,miR-29,miR-29b, miR-34a, miR-103, miR-200a, miR-200b, miR-200c, miR-210, miR-326, miR-338-3p, miR-494 and miR-497,and there were 22 down-regulated,being Let-7a,Let-7b,Let-7d,Let-7e,miR-19a,miR-19b-1, miR-20a,miR-20b,miR-23a,miR-23b,miR-25,miR-98,miR-107,miR-122a,miR-125a,miR-125b, miR-145,miR-181a,miR-181c,miR-335,miR-384-5p and miR-422a. Eight miRNA had significant changes at 24 hours after ROSC,in which miR-15a,miR-21,miR-34a,miR-497 were up-regulated respectively for 6.831±2.625,8.122±3.442,5.349±2.010,6.590±3.689 times,and miR-125b,miR-145,Let-7a,Let-7e were down-regulated respectively for 0.122±0.039,0.199±0.096,0.191±0.069,0.160±0.082 times. The apoptosis rate of cerebral cortex was increased significantly in CA-CPR group〔(32.23±5.31)%〕compared with that in normal control group〔(3.66±1.34)%〕and sham operation group〔(4.98±1.84)%,both P down-regulated respectively for 0.122±0.039,0.199±0.096,0.191±0.069,0.160±0.082 times. The apoptosis rate of cerebral cortex was increased significantly in CA-CPR group〔(32.23±5.31)%〕compared with that in normal control group〔(3.66±1.34)%〕and sham operation group〔(4.98±1.84)%,both P<0.01〕. Conclusions In early period after CA-CPR,obvious neurocyte apoptosis may be found in brain tissue of rats,and in the mean time, changes in apoptosis-related miRNA expression in cerebral cortex occur. The various types of miRNA with significant changes possibly play important roles in cerebral protection after CA-CPR in rats.