Changes in expression of cold-inducible RNA-binding protein in hippocampus during brain injury in a rat model of cardiac arrest-cardiopulmonary resuscitation

Objective To evaluate the changes in expression of cold-inducible RNA-binding protein (CIRP) in hippocampus during brain injury in a rat model of cardiac arrest-cardiopulmonary resuscitation. Methods Seventy-two clean-grade healthy male Sprague-Dawley rats, weighing 280-350 g, aged 8-10 weeks, were divided into 2 groups using a random number table: sham operation group (S group, n=18) and ischemia-reperfusion group (I/R group, n=54). Tracheal intubation was performed and artery and veins were punctured in group S. Ventricular fibrillation was induced by transoesophageal cardiac pacing to establish the model of cardiac arrest in group I/R.Rats were sacrificed at 12, 24 and 48 h after resuscitation and the hippocampus was harvested for determination of CIRP, tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) protein and mRNA expression (by quantitative polymerase chain reaction or Western blot) and for determination of pathological changes of hippocampi (with a light microscope). Results Compared with group S, the expression of CIRP mRNA in hippocampus was up-regulated at 24 and 48 h after resuscitation, the expression of TNF-α mRNA was up-regulated at 12, 24 and 48 h after resuscitation, the expression of IL-1β mRNA was up-regulated at 12 and 24 h after resuscitation, and the expression of CIRP, TNF-α and IL-1β was up-regulated at 12, 24 and 48 h after resuscitation in group I/R (P<0.05). Pathological changes in hippocampal CA1 region were found in group I/R. Conclusion The expression of CIRP in hippocampus is up-regulated, which promotes central inflammatory responses during brain injury in a rat model of cardiac arrest-cardiopulmonary resuscitation. Key words: RNA-binding protein; Heart arrest; Cardiopulmonary resuscitation; Brain injuries