ABSTRACT
Objective:To investigate the effect of sodium butyrate (NaB) on renal and intestinal injury after cardiac arrest and cardiopulmonary resuscitation (CA-CPR) and its related mechanism.Methods:Twenty-four domestic healthy male swines were randomly divided into 3 groups: sham group ( n=6), CA-CPR group ( n=10) and NaB group ( n=8). The animals only underwent operational preparation in the sham group. The animal model of CA and CPR was established by 9 min of ventricular fibrillation induced by electrical stimulation in the ventricle and then 6 min of CPR in the CA-CPR and NaB groups. At 5 min after resuscitation, a dose of 75 mg/kg of NaB was intravenously infused for 1 h in the NaB group, and meanwhile the same volume of vehicle was intravenously infused in the sham and CA-CPR groups. At 1, 2, 4, and 24 h after resuscitation, blood samples were collected to detect the renal and intestinal injury biomarkers, such as creatinine (Cr), blood urea nitrogen (BUN), intestinal fatty acid binding protein (IFABP), and diamine oxidase (DAO). At 24 h after resuscitation, renal and intestinal tissue specimens were harvested to detect the protein markers of cell autophagy including microtubule-associated protein light chain 3 Ⅱ (LC3Ⅱ) and p62 expression, and also renal and intestinal apoptosis. Statistical analysis was performed by SPSS software, and continuous variables were compared with one-way analysis of variance among the groups. Results:After CA-CPR, the renal and intestinal injury biomarkers including Cr, BUN, IFABP, and DAO were significantly increased at all time points after resuscitation in the CA-CPR and NaB groups compared with the sham group (all P<0.05). The injury biomarkers mentioned-above were significantly lower at all time points after resuscitation in the NaB group than in the CA-CPR group [Cr (μmol/L): (90±5) vs. (127±9) at 1 h, (135±14) vs. (168±9) at 2 h, (174±10) vs. (211±12) at 4 h, (192±10) vs. (253±13) at 24 h; BUN (mmol/L): (10.5±1.0) vs. (12.3±1.0) at 1 h, (12.2±1.2) vs. (15.3±0.9) at 2 h, (13.6±1.3) vs. (18.3±1.2) at 4 h, (15.4±1.4) vs. (21.5±1.4) at 24 h; IFABP (pg/mL): (502±33) vs. (554±32) at 1 h, (574±52) vs. (644±41) at 2 h, (646±44) vs. (732±43) at 4 h, (711±42) vs. (828±42) at 24 h; DAO (U/mL): (8.6±1.0) vs. (10.5±0.9) at 1 h, (10.6±1.2) vs. (12.8±1.0) at 2 h, (12.1±1.0) vs. (15.0±1.0) at 4 h, (14.1±1.1) vs. (17.6±1.0) at 24 h, (all P<0.05)]. Renal and intestinal tissue detection indicated that cell autophagy and apoptosis were significantly increased after resuscitation in the CA-CPR and NaB groups compared with the sham group, which was indicated by significantly increased LC3Ⅱ and decreased p62 expression, and markedly elevated apoptosis index (all P<0.05). However, cell autophagy and apoptosis in the kidney and intestine were significantly milder after resuscitation in the NaB group than in the CA-CPR group [renal LC3 Ⅱ: (1.15±0.17) vs. (2.23±0.31), p62: (1.60±0.10) vs. (1.17±0.08), apoptosis index (%): (21.2±5.3) vs. (50.9±7.9); intestinal LC3 Ⅱ: (1.03±0.17) vs. (1.71±0.21), p62: (1.30±0.29) vs. (0.79±0.29), apoptosis index (%): (25.6±6.1) vs. (61.7±10.7), all P<0.05]. Conclusions:NaB could alleviate the severity of renal and intestinal damage after CA-CPR in swine, and its protective mechanism may be related to the inhibition of cell autophagy and apoptosis.
ABSTRACT
Objective To investigate the effects of rapid hypothermia induced via esophagus on intestinal mucous injury in early stage after cardiopulmonary resuscitation (CPR) in a swine model of cardiac arrest.Methods Twenty-seven male domestic pigs weighing (36±2)kg were utilized.The animals were randomly crandom number divided into 3 groups (n=9 in each):normothermia group (NT group),surface cooling group (SC group),and esophageal cooling group (EC group).The pig model was established by 8 mins of untreated ventricular fibrillation and then 5 mins of CPR.At 5 mins after restoration of spontaneous circulation (ROSC),therapeutic hypothermia was applied by either an esophageal cooling device in the EC group or a surface cooling blanket in the SC group to reach a targeted temperature of 33 ℃ maintained for 24 h after ROSC,and then followed by warming up in a rate of 1 ℃ / hr for 5 hrs.A normal temperature of (38.0±0.5)℃ was maintained throughout the experiment in the NT group.The core temperature was continuously monitored during a period of 30 h after ROSC.At 3 h,6 h,12 h,24 h and 30 h after ROSC,intestinal fatty acid binding protein (IFABP) content and diamine oxidase (DAO) activity in serum were measured by ELISA.At 30 h after ROSC,the pigs were sacrificed,and then intestinal tissue was rapidly obtained for the determination of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) contents by ELISA,cell apoptosis by TUNEL,and caspase-3 expression by immunohistochemistry.Results The rate of temperature decrease was 2.8 ℃/h and the time required for target temperature was 102 min in the EC group,while the rate of temperature decrease was 1.5 /h and the time consumed for target temperature was 185 mins in the SC group,which suggested the efficacy of cooling was significantly better in the EC group than that in the SC group (both P＜0.05).Compared with the NT group,serum IFABP content and DAO activity were significantly decreased at 3 hrs after ROSC in the EC group and at 6 hrs after ROSC in the SC group.Compared with the SC group,serum IFABP content at 6 hrs after ROSC and DAO activity at 12 h after ROSC were significantly decreased in the EC group IFABP (pg/mL):(710±32) vs.(777±52) at 6 h,(870±49) vs.(960±64) at 12 h,(1 022±65)vs.(1 143±63) at 24 h,(882±71) vs.(1 006±45) at 30 h DAO (U/mL):(39.9±1.9) vs.(43.4±3.2) at 12 h,(30.6±2.4) vs.(34.0±3.1) at 24 h,(26.1±2.7) vs.(29.4±2.2) at 30 h,all P＜0.05.In the intestinal tissue,TNF-α and IL-6 contents were significantly reduced,and cell apoptosis index and caspase-3 expression were significantly decreased in the SC and EC groups compared with the NT group.Additionally,inflammatory response and cell apoptosis in intestinal tissue were further significantly lesser in the EC group compared with the SC group TNF-α (pg/mL):(721±94) vs.(922±125);IL-6(pg/mL):(454±69) vs.(697±132);Apoptotic index(％):(6.2±2.6)vs.(12.8±3.0);caspase-3 expression (IOD):(8.9±1.6) vs.(15.9±1.9),all P＜0.05.Conclusions In a swine model of cardiac arrest,rapid hypothermia could be successfully induced via esophagus and consequently produced a greater protective effect on post-resuscitation intestinal injury compared with the conventional surface cooling.The protective mechanisms are associated with the inhibition of inflammatory response and cell apoptosis.