To investigate the role and mechanism of sodium valproate (VPA) in cardiac and cerebral injuries after cardiopulmonary resuscitation (CPR) in pigs.

Twenty-five healthy male domestic pigs, weighing (37±3) kg, were randomly divided into the sham group (n=6), CPR group (n=10), and CPR+VPA group (n=9). Cardiac arrest was induced by alternating current delivered via a pacing catheter in the right ventricle and untreated for 9 min, and then CPR was performed for 6 min, in which this procedure was used to establish the animal model of cardiac arrest and CPR. At 5 min after resuscitation, a dose of 150 mg/kg of VPA was infused with a pump via the femoral vein in 1 h in the CPR+VAP group. At 1 h, 2 h, 4 h and 24 h after resuscitation, blood samples were drawn from the femoral vein, and then used to measure the serum concentrations of cardiac troponin I (cTnI), creatine kinase MB (CKMB), neuron specific enolase (NSE), and S100B protein (S100B) by ELISA. At 24 h after resuscitation, the animals were euthanized, and then tissue specimens in the left myocardium and brain cortex were rapidly harvested to detect the expression levels of C/EBP homologous protein (CHOP), caspase 12, and caspase 3 by Western blot, and the rate of apoptotic cells was detected by TUNEL. Continuous variables were compared with one way analysis of variance among the three groups.

(1) After resuscitation, cardiac and cerebral injury biomarkers including cTnI, CKMB, NSE, and S100B in serum were significantly increased in the CPR and CPR+VPA groups compared with the Sham group (all P<0.05). The serum concentrations of cTnI and NSE starting 1 h after resuscitation and the serum concentrations of CKMB and S100B starting 2 h after resuscitation were significantly decreased in the CPR+VPA group compared to the CPR group (all P<0.05). (2) Those proteins related to cell apoptosis mediated by endoplasmic reticulum stress, including CHOP, caspase 12, and caspase 3, were significantly increased, and meanwhile apoptosis index was markedly elevated after resuscitation in the CPR and CPR+VPA groups compared with the Sham group (all P<0.05). Nevertheless, the expression levels of CHOP, caspase 12, and caspase 3 were significantly decreased, and cell apoptosis was markedly reduced in the heart and brain after resuscitation in the CPR+VPA group compared to the CPR group (all P<0.05).

VPA can alleviate cardiac and cerebral injuries after CPR in pigs, and its mechanism may be possibly related to the inhibition of cell apoptosis mediated by endoplasmic reticulum stress.

Cardiac arrest; Cardiopulmonary resuscitation; Cardiac injury; Brain injury; Sodium valproate; Endoplasmic reticulum stress; Apoptosis; Pig