Resolvin D1 alleviates cerebral ischemia/reperfusion injury in rats by inhibiting NLRP3 signaling pathway.

Abstract

The purpose of the present study was to investigate the role of resolvin D1 (RvD1) in cerebral ischemia/ reperfusion (I/R) injury in rats and its mechanism. A total of 60 adult male Wistar rats were divided into 3 groups using a random number table, including sham-operation group (Sham group, n=20), cerebral I/R injury group (I/R group, n=20) and cerebral I/R injury + RvD1 pretreatment group (I/R + RvD1 group, n=20). The model of focal I/R injury was established using suture method through 30 min of ischemia and 24 h of reperfusion. In I/R + RvD1 group, the rats were intraperitoneally injected with RvD1 (4 mg/kg/d) at 7 d before operation, while those in the Sham group and I/R group were injected with an equal volume of normal saline. After reperfusion, the area of cerebral infarction was evaluated by means of 2,3,5-triphenyltetrazolium chloride (TTC) staining. Then hematoxylin and eosin (H&E) staining was applied to observe the status of brain tissue injury in each group of rats, and the expression of malondialdehyde (MDA), a marker of oxidative stress, in each group of brain tissues was detected via an oxidative stress detection kit. Moreover, reverse transcription-polymerase chain reaction (RT-PCR) assay was performed to measure the levels of inflammation-related genes [interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α)] in the brain tissues of each group of rats, and the neuronal apoptosis level in the brain tissues in each group was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Finally, the expression levels of proteins related to the inflammasome signaling pathway were detected via Western blotting assay. It was indicated in the results of TTC staining and H&E staining that RvD1 could remarkably decrease the area of I/R-induced cerebral infarction and relieve nervous tissue injury (P<0.05). The results of TUNEL staining revealed that the cerebral neuronal apoptosis induced by I/R injury was alleviated by RvD1 (P<0.05). In addition, RvD1 lowered the levels of inflammatory factors and MDA in the brain tissues of rats with I/R injury (P<0.05). Furthermore, it was discovered that RvD1 repressed the protein expression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) in the brain tissues of rats with I/R injury (P<0.05). The protective effect of RvD1 on the rats against cerebral I/R injury may be related to its inhibition on NLRP3 inflammasome, and RvD1 is expected to become a targeted drug for the clinical treatment of cerebral I/R injury.