Intracarotid cold saline infusion contributes to neuroprotection in MCAO-induced ischemic stroke in rats via serum and glucocorticoid-regulated kinase 1.

Intracarotid cold saline infusion (ICSI) brings about neuroprotective effects in ischemic stroke. However, the involvement of serum and glucocorticoid-regulated kinase 1 (SGK1) in the underlying mechanism of ICSI is not fully understood; therefore, we used the rat middle cerebral artery occlusion (MCAO) model to investigate the neuroprotective effects of ICSI on ischemic stroke in rats, as well as the involvement of SGK1 in these effects. ICSI decreased infarct size and brain swelling, as determined by 2,3,5-triphenyltetrazolium chloride staining and the dry-wet weight method, respectively. The results of terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL) and Nissl staining showed that ICSI also suppressed apoptosis and increased the relative integral optical density (IOD) values of Nissl bodies in the rat MCAO model. Regarding the mechanism, the results of immunohistochemistry and western blotting revealed that ICSI upregulated SGK1 expression and downregulated beclin-1 and LC-3 expression in the rat MCAO model. In addition, SGK1 knockdown increased ICSI-mediated infarct size and brain swelling, promoted apoptosis, and reduced the IOD values of Nissl bodies in the rat MCAO model. In addition, we found that SGK1 knockdown upregulated beclin-1 and LC-3 expression mediated by ICSI. Overall, ICSI had a neuroprotective effect on ischemic stroke after reperfusion by upregulating SGK1 and inhibiting autophagy. [ABSTRACT FROM AUTHOR]