Effects of oleanolic acid on early brain injury after subarachnoid hemorrhage through SIRT1 / 国际生物医学工程杂志

ABSTRACT

Objective:To investigate the effect of oleanolic acid (OA) on Sirtuin1 (SIRT1)-mediated high-mobility group box 1(HMGB1) deacetylation in the early brain injury after subarachnoid hemorrhage (SAH).Methods:A total of 176 male Sprague-Dawley rats were randomly divided into Sham operation (Sham group) ( n=48), SAH group ( n=48), OA group ( n=48) and Sirtinol group ( n=32). Rats in the SAH group, OA group and the Sirtinol group all adopted internal carotid artery puncture to construct SAH model, while rats in the sham group did not adopt puncture. One hour after modeling, the rats in the OA group were given intraperitoneal injection of OA (20 mg/kg), and the rats in the Sirtinol group were given intracerebroventricular injection of Sirtinol (2 mmol/L, 30 μL/kg). The rats in the sham group and SAH group were injected with equal volumes of sodium chloride injection. The SAH score and neurological score were performed 24 h after SAH, and the water content in the brain tissue and Evans blue exudation rate were measured. The expressions of HMGB1, SIRT1 and acetylated HMGB1 proteins in the brain tissue of rats were detected by Western Blot. The expression of HMGB1 mRNA in the brain of the rats was detected by quantitative real-time PCR. The distribution of HMGB1 protein in the brain of the rats was observed by immunofluorescence staining. TUNEL staining was used to observe the neuronal apoptosis in the brain tissue of the rats. Results:Compared with the SAH group, the SAH score of the OA group was significantly reduced ( P<0.001), the Garcia score was increased ( P<0.01), and the brain water content and Evans blue exudation rate were both reduced (all P<0.01). Compared with the OA group, the SAH score of the Sirtinol group was increased ( P<0.01), the Garcia score was significantly decreased ( P<0.001), and the brain water content and Evans blue exudation rate were both increased (all P<0.01). The results of Western Blot and real-time fluorescent quantitative PCR showed that, compared with the SAH group, the protein level ( P<0.01) and mRNA level ( P<0.05) of HMGB1 in the OA group were decreased, the expression of SIRT1 protein was significantly increased ( P<0.001), and the expression of acetylated HMGB1 protein was decreased ( P<0.01). Immunofluorescence staining showed that OA inhibited the migration of HMGB1 protein from the nucleus to the cytoplasm. TUNEL staining showed that OA could effectively reduce the number of TUNEL-positive cells. Compared with the OA group, Sirtinol significantly increased the number of TUNEL-positive cells. Conclusions:OA can reduce the release of HMGB1 through the SIRT1/HMGB1 pathway, thereby protecting the early brain injury after SAH.