Astragaloside IV attenuates cerebral ischemia‑reperfusion injury in rats through the inhibition of calcium‑sensing receptor‑mediated apoptosis.

Cerebral ischemia‑reperfusion injury (CIRI), caused by the reperfusion of blocked vessels following ischemic stroke, can lead to secondary brain injury. Throughout CIRI, apoptosis serves an important role. Astragaloside IV is a potential neuroprotectant that alleviates CIRI by inhibiting apoptosis. The calcium‑sensing receptor (CaSR) is a G‑protein‑coupled receptor, the activation of which aggravates ischemia‑reperfusion injury. The aim of the present study was to investigate whether the protective effect of Astragaloside IV on CIRI may be associated with the regulation of CaSR. A rat middle cerebral artery occlusion/reperfusion (MCAO/R) model and an oxygen and glucose deprivation/reoxygenation (OGD/R) model of pheochromocytoma (PC12) cells were used to study the neuronal injury induced by CIRI. Neurological function scores (NFS), 2,3,5‑triphe‑nylterazolium chloride and hematoxylin and eosin staining were used to determine brain damage in rats. Cell viability was measured to evaluate the injury of OGD/R PC12 cells. Western blotting was used to examine the expression of proteins associated with apoptosis and CaSR. The CaSR antagonist NPS‑2143 and agonist GdCl3 were used to further confirm the effects of CaSR during the process of apoptosis. The results demonstrated that Astragaloside IV alleviated CIRI by decreasing the NFS of rats, reducing the infarction volume of the brain and promoting the viability of PC12 cells, as well as inhibiting the expression of cleaved caspase‑3 and CaSR, which was induced by CIRI. The results of the present study suggested that the activation of CaSR may be involved in CIRI‑induced brain damage in rats, and that Astragaloside IV may alleviate CIRI by inhibiting CaSR activation‑induced apoptosis.