Objective: To study the effects of trioxygen pretreatment on cerebral ischemia/reperfusion (I/R) injury in rats.
Methods: 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.
Results: 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].
Conclusions: 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.