Effects of trioxygen preconditioning on cerebral ischemia/reperfusion injury and glutamate receptor in rats

Abstract

To study the effects of trioxygen pretreatment on cerebral ischemia/reperfusion (I/R) injury in rats. A total of 24 clean grade male Sprague-Dawley (SD) rats were randomly divided into Sham group, brain I/R group (I/R group) and Ozone pretreatment group (Ozone group), with 8 rats in each group. The animals were routinely fed, and the operation was performed 5 days after the intervention of Ozone group by intraperitoneal injection of trioxygen water (concentration 80 mg/L, 0.01 mL/g), and the Sham group and I/R group were injected with equal volume normal saline. The Sham group only separated the arteries without ligation, and the I/R group and Ozone group established the rat cerebral I/R model. Neurological deficit score (NDS) was performed 2 hours after ischemia and modified neurological deficit score (mNSS) was performed 24 hours after reperfusion. Brain tissue was collected after anesthesia. Cerebral infarction was observed by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining and the percentage of cerebral infarction volume was calculated. Protein expression of metabolic glutamate receptor 5 (mGluR5) and ionic glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) subunit GluA2 in cerebral ischemic penumbra was determined by Western blotting. Compared with the Sham group, NDS score, mNSS score and percentage of cerebral infarction volume in I/R group were increased [NDS score: 2.63±0.52 vs. 0, mNSS score: 9.63±1.19 vs. 1.13±0.64, cerebral infarction volume: (41.25±2.93)% vs. 0%, all P < 0.05], and expressions of mGluR5 and GluA2 in penumbra area of cerebral ischemia were decreased [mGluR5 protein (mGluR5/β-actin): 0.44±0.14 vs. 1.00±0.10, GluA2 protein (GluA2/β-actin): 0.23±0.08 vs. 1.00±0.25, both P < 0.05]. Compared with the I/R group, mNSS score and percentage of cerebral infarction volume in the Ozone group were decreased [mNSS score: 7.00±1.20 vs. 9.63±1.19, cerebral infarction volume: (27.23±6.21)% vs. (41.25±2.93)%, both P < 0.05], and mGluR5 and GluA2 expressions in the penumbra of cerebral ischemia were up-regulated [mGluR5 protein (mGluR5/β-actin): 0.81±0.10 vs. 0.44±0.14, GluA2 protein (GluA2/β-actin): 0.76±0.13 vs. 0.23±0.08, both P < 0.05]. Trioxygen preconditioning can alleviate cerebral I/R injury in rats, and its mechanism may be related to the upregulation of GluR5 and GluA2 in the ischemic penumbra.