Effects of hypotonic pyruvate oral rehydration solution on brain injury in rats subjected to asphyxial cardiac arrest

Abstract

Objective To investigate the effect of hypotonic pyruvate oral rehydration solution on brain injury subjected asphyxial cardiac arrest in rats. Methods Clean male SD rats, weighing 300-350 g, were divided into 3 groups according to random number table method: sham operation group (group S, n=8), asphyxial cardiac arrest recovery plus experimental water group (group C, n=12) and asphyxial cardiac arrest recovery plus hypotonic pyruvate oral rehydration solution group (group P, n=12). At 30 min after the restoration of spontaneous circulation, group P was gastrically injected through gavage of pyruvate oral rehydration solution 12 mL, instead of experimental water in group C(3 mL at 30 min intervals), then drinking pyruvate oral rehydration solution to replace experimental water in the first day. While rats in group S were not induced asphyxial cardiac arrest and cardiopulmonary resuscitation. Pyruvate levels of brain frontal cortex was measured at 24 h after restoration of spontaneous circulation. The scores of neurological deficits were evaluated 24 h, 72 h and 7 d following the cardiac arrest restoration. The water maze tests used to evaluate spatial learning and memory deficit were recorded 4-7 d post-restoration of spontaneous circulation. Morphological changes of neurons in the hippocampal CA1 region were observed on 7 d after the cardiac arrest recovery. Results Compared with group S, brain pyruvate levels in group C were decreased, but greatly increased in group P, in groups C and P, the neurological deficit score and the number of viable neurons in hippocampal CA1 region were reduced, the escape latency was prolonged, and the platform quadrant enter time percentage and the target quadrant residence time percentage were decreased at each time point, the differences were statistically significant(with P values below 0.05). However, compared with group C, in group P with increased pyruvate in the brain tissue, the score of nerve defect and the number of survival neurons in hippocampal CA1 region were significantly improved, the escape latency was shortened, and the two percentages of the platform quadrant were also preserved at each time point, the differences were statistically significant(with P values below 0.05). Conclusion Oral hypotonic pyruvate oral rehydration solution relieved the brain damage after asphyxial cardiac arrest in rats. Key words: Pyruvic acid; Fluid therapy; Hypotonic solutions; Heart arrest; Resuscitation; Brain injuries; Rats